sustainable agriculture in the himalaya (dw) (2)
TRANSCRIPT
[1]
Sustainable agriculture in the Himalaya: could
widespread use of agroforestry techniques improve
productivity, land stability and water supply?
David Wellstead
[2]
Abstract
The Himalaya is a poor region with many diverse and often isolated rural
groups, living across vastly different climatic and topographic locations. This
review aims to highlight the problems facing Himalayan agriculture and
examine the suitability of agroforestry as a sustainable alternative to
traditional farming practices. For successful implementation, the social,
political and economic background should be fully understood. Crop
productivity has decreased in recent times, with widespread erosion
contributing to unpredictable over-land water flow, accentuated by the
effects of climate change. Poor soil fertility and inadequate water supplies
have manifested as the main abiotic limitations. Sustainable agriculture is
ideally suited to the Himalaya, with agroforestry providing a flexible and
affordable model which combines tree and crop species using a number of
techniques. The diversity of Himalayan species, their many uses and
importance to local populations provides a favourable biological and social
start-point. Net gains in productivity, sustainability and lifestyle are possible,
but must overcome the effects of competitive interactions between species;
management of vegetation canopies, understanding allelopathic interactions
and managing species’ root profiles are key to this. Biomass transfer can be
achieved through root and shoot pruning and green leaf manure application.
Land-owners have access to more subsistence resources as a result of the
species grown. Employment and trade opportunities may also arise through
the production of cash crops and livestock, helping to combat the rural-
urban migration trend. Increased biodiversity and the introduction of
nitrogen-fixing species, particularly, show positive effects regarding soil
fertility and reduced run-off and leeching. Water movement is more uniform
due to increased soil health and stability. Water harvesting may also
constitute a valuable technique for providing year-round water supplies
whilst benefitting upstream and downstream users.
This review highlighted the need for sustainable agriculture in the Himalaya,
suggesting agroforestry as a potentially successful and apt method for
alleviating poor productivity, land stability and water supply. Unilateral
development efforts must continue in the region, with further scientific
research into competitive interactions between specific tree and crop
species.
[3]
Acknowledgements
I would like to thank Professor Colin Black for his enthusiastic guidance and
support throughout the year. During my 2009 visit to the Himalaya, my work on
Alina Schick’s Kaule eV Agroforestry Project proved invaluable and was
facilitated by Volunteers’ Initiative Nepal (VIN). VIN’s director Bhupendra
Ghimire was a huge help whilst overseas. I would also like to thank my family
and friends for their encouragement.
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Abstract.........................................................................................2
Acknowledgements..........................................................................3
Table of Contents............................................................................4
Chapter 1: The Himalaya
1.1 Introduction.........................................................................6
1.2 Geography and geomorphology..............................................8
1.3 Political, economic and social background...............................10
1.4 Current agriculture and productivity.......................................14
Chapter 2: Issues and challenges
2.1 Climate change...................................................................22
2.2 Water availability................................................................23
2.3 Indigenous culture and religion.............................................26
Chapter 3: Sustainable agriculture and development..................28
Chapter 4: Agroforestry..............................................................32
Chapter 5: Implementation of agroforestry techniques: potential
benefits and limitations
5.1 Limitations of the Himalayan region.......................................36
5.2 Resource capture by plants...................................................39
5.3 Competition and productivity.................................................47
Table of Contents
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5.4 Erosion and soil degradation.................................................51
5.5 Sustaining and improving Himalayan water flow.......................54
5.6 Introducing livestock............................................................58
Chapter 6: Conclusions...............................................................60
Chapter 7: Glossary of key organisations...................................63
Chapter 8: Bibliography..............................................................65
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Chapter 1: The Himalaya
1.1 Introduction
‘In these hills, Nature's hospitality eclipses all men can ever do. The enchanting
beauties of the Himalayas, their bracing climate and the soothing green that
envelopes you leaves nothing more to be desired. I wonder whether the scenery
of these hills and the climate are to be surpassed, if qualified, by any of the
beauty spots of the world.’ (Mahatma Gandhi, 1921)
The Himalaya has long had the epithet of being one of Earth’s most diverse and
picturesque locations - justified by the largely unparalleled variation in
topography, vegetation patterns, climate and inhabitants.
The Himalaya stretches from Pakistani-controlled Kashmir at the most northerly
tip, south-east through India, Nepal and Bhutan, intersecting the Indian
subcontinent from the vast Tibetan Plateau. It stretches for approximately 2400
km with more than 40 mountains exceeding 7000 m in height and many over
8000 m (Yang and Zheng, 2004). This mountainous region is the origin of many
vital water sources which are not only necessary for the survival of regional
populations but are also essential components of hydrological and nutrient
cycles. For example, the numerous downstream rivers serve an important role in
the carbon fluxes which are recognised as a major component in regional and
global environmental change (Rai and Sharma, 2004). Given the location of the
Himalaya, there is also an inherent level of seismic activity which is thought to
be induced by variation in water storage which correlates with seasonal
differences in climatic conditions (Bettinelli et al., 2008).
This report focuses on the Himalayan range, with the Nepalese Himalaya being
of particular interest due to the relative large quantity of research undertaken by
non-governmental organisations (NGOs), universities and bureaucrats in recent
years, although many holistic ideas as well as specific agroforestry (AF)
techniques are implementable across the region.
The Himalaya is full of natural wealth, including both renewable and non-
renewable resources. Amongst its non-renewable resources are deposits of
boron, lead, lithium, coal, chromium, ores of iron, copper, tungsten, zinc and
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deposits of building material such as limestone, dolomite and marble. These
deposits occur across the length and breadth of the Himalaya. Despite the
substantial mineral wealth in the Himalaya, the common image of resources
there is of water and forests (UNPAN, 2008).
Objective
The objective of this project was to review the many interlinked problems facing
agriculture across the Himalaya and the wide range of sustainable technologies
currently in operation which may help to combat such problems, with particular
emphasis on agroforestry models which may help to improve productivity, land
stability and water supply in the future.
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1.2 Geography and geomorphology
Figure 1.1: Satellite image of the Himalayan region between Uttar Pradesh and
Arunachal Pradesh (Adapted from Bowen, 2008. http://geogdata.csun.edu, cf. W1)
The mountainous Himalayan region extends over a distance of 2400 km and is
the meeting point between the northerly Eurasian and southerly Indo-Australian
tectonic plates. The satellite image in Figure 1.1 shows the main geo-political
divisions and differing topographic gradients.
There are a numerous high peaks, many with historical, geological and cultural
significance. As the highest peak on the planet at 8848 m, Mount Everest is the
most recognisable symbol of the entire Himalaya and remains an elusive
challenge to mountaineers, decades after the globally reported summit of Sir
Edmund Hillary and sherpa Tensing in 1953. Sikhs, Buddhists and Hindus all
regard various peaks as sacred due to the intertwining of historical reverence
and numerous tales of deities travelling the region finding enlightenment (Tanka
and Karubaki, 1995). Mount Kailash is notable as one of the world’s highest
peaks not to be climbed in recent history as this is precluded by religious
sensitivity (Han, 1998).
The Himalaya represents the most recently-formed mountain range on the
planet and is the result of an ongoing orogeny between two continental plates.
Initial continent-continent tectonic interactions are thought to have begun in the
late cretaceous period (around 65-55 Ma; Ding et al., 2005), although the
evidence is circumstantial and complex as unification of records from various
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sources to create an overall picture is not straightforward. Rock type and
location, time and speed of plate movement, rotation of different geographical
points (India has rotated 45° counter-clockwise in the north western Himalaya
since the K-T mass extinction, whilst north central Nepal has rotated 10-15° in
the same direction; Klootwijk et al., 1985) and wider historical knowledge of
tectonic movements all contribute to this analysis. Even the present day
situation concerning the geological composition and ongoing changes in the
region is poorly understood as Burbank et al. (1996) stated that “the topography
of tectonically active mountain ranges reflects a poorly understood competition
between bedrock uplift and erosion”, in specific regard to their research on
bedrock incision, rock uplift and threshold hillslopes in the Himalaya.
Over time, three main zones have been widely described in the academic
literature, which act primarily to provide a categorised determination of altitude,
along with the associated climatic and biogeographical conditions.
The Mahabharat Range (Mahabharat Lekh) is commonly referred to as the
Lesser Himalaya (or colloquially, as the “foothills”) and is elevated between
1500-3000 m. At these altitudes, sub-tropical and temperate forests are found,
including the Western (through Pakistan, India, Nepal) and Eastern (through
Nepal, Sikkim, Bhutan) Himalayan Broadleaf Forests.
The Midlands are located north of the Lesser Himalaya and encompass regions
up to 4000 m; temperate coniferous forests are present towards higher
elevations, such as the Himalayan Subalpine Conifer Forests. Interestingly, this
is a hotspot for Rhododendron diversity, with some varieties resisting
temperatures of -23 °C (Sakai, 1981).
The Greater Himalaya is located above 4000 m and demonstrates most
impressively the huge tectonic forces leading to their creation. The unceasing
denudation caused by weathering and erosion mean that some peaks are
decreasing in height whilst others may simultaneously be increasing in height
(Molnar and Tapponnier, 1975).
These three broad categories are by no means all-encompassing for the
Himalaya but provide a context for comparing specific geographical locations.
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Mapping of the Himalaya has improved rapidly in recent years, with many
organisations focusing specifically on this task. A number of modern methods
are now being used to give an accurate and detailed account of the region, such
as geographical interface system (GIS) mapping and satellite imaging.
The origins of the city of Pokhara demonstrate the likelihood of current
understanding being inadequate in providing full comprehension of the formation
and ongoing changes in the Himalaya. Situated on the shore of Nepal’s second
largest lake, Phewa Tal, it was long thought that the valley originated from the
drying up of a larger initial lake in a similar manner to the Kathmandu and
Kashmir valleys. Careful observations of the sediments filling the basin indicate
that the Pokhara valley was in fact formed by a catastrophic giant debris flow
five centuries ago. The emblematic site is still rising up the front of the Greater
Himalaya and is maintained by sporadic collapses of the mountain walls
controlled by a combination of both glacial and seismo-tectonic dynamics (Fort,
2010). Such inter-disciplinary complexities are difficult to combine to give a full
picture of the constantly changing biogeographical situation, for any given part
of the Himalaya.
1.3 Political, economic and social background
People’s way of life, as anywhere in the world, is the culmination of hundreds of
years of evolving beliefs, traditions and practices. The Himalaya is a region
encompassing countries plus the Tibet Autonomous Region (TAR) and falling
entirely within the ‘very poor’ income category under the International Monetary
Fund (IMF) classification (with the exception of India, defined by the IMF as
‘Upper-Lower’ average income). Consequently, the way of life and cultures of
the area may be more strictly followed and vehemently protected than those of
richer, more developed nations whose values lie in a generally more materialistic
and economic success-based stratum (Alfaro, 2008). Indeed, educating
underprivileged groups to defined normal levels is often difficult, especially if the
group is very primitive or nomadic (Samal et al., 2001). This is of extreme
importance when implementing change across the region, as anything new must
be accepted and advocated by local populations for a successful transition to
new farming techniques, which may infringe lifestyle and anthropogenic norms.
Women generally maintain a traditional role as keepers of the home, although in
many groups this stretches to farming responsibilities at least equal to those of
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males. Literacy amongst women is significantly lower than amongst men,
although evidence from the 2001 Indian Census suggested the gap had
diminished (Fig. 1.2). Current opinion suggests that this gap has narrowed still
further (Vepa, 2007), although comparable empirical evidence may not become
available until the next census in 2011. Work by Pant (2006) shows the trend for
greater male literacy prevails throughout the region.
Many factors contribute to poverty and under-development in the region.
Political stability and reform and fairer distribution of wealth are two
underpinning issues which, if not addressed, will make implementation of
changes in farming techniques more difficult. In the past 50 years, development
efforts in Nepal have failed to touch the poor and so contributed to a rise in
unemployment, poverty, and rural/urban inequality, which has significantly
increased frustration and resentment among disadvantaged youths in rural and
remote areas, leading eventually to civil war (Sharma, 2006).
Figure 1.2: Male and female literacy rates across various Indian states in 1991 and 2001 alongside the gaps in literacy from the respective years (adapted from http://www.thesouthasian.org, cf. W2).
The end of the decade-long, Maoist-led civil war in 2006 was followed by a
significant increase in foreign aid and humanitarian activity in Nepal, although
agricultural investment from the government is still low and financial
liberalisation has not seen any increase in credit availability for farmers
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(Independent Evaluation Group of the World Bank, 2008). Non-governmental
organisations have played a key role in development efforts across the Himalaya
for some time, with many examples of NGOs being absolutely crucial to
providing help to governmental support agencies, which would be “completely
overwhelmed”, alone (Jasanoff, 1997). The ongoing conflict in Kashmir around
the Karakoram and Ladakh ranges has led to 12 identifiable groups in the region
being forced to leave their home territories over the past two decades, due to
internal or external factors surrounding the conflict (Shekhawat, 2006).
Displacement obviously makes implementation of new ideas difficult; with no
guarantee of rightful land ownership, any subsequent implementation of new
land-usage is likely to be ineffective over an indeterminate period.
Poverty and migration
The topography of the land dictates that human populations live across an
enormously variable climatic and environmental gradient throughout the
Himalayan region, ranging from high and mountainous areas, to the mid-hills
and foothills. This often creates isolated communities cut-off from regular
access to the outside world. The implications are significant and numerous as
these communities may be self-sufficient but lack any sense of entrepreneurship
or the value of money. Access to healthcare is greatly reduced as, without
medical professionals, or the money to fund travel, people turn to unreliable
sources of information or simply live with ailments of various severity.
Much of the Himalaya is characterised by a very low economic growth rate
combined with rapid population growth, exacerbating the already low per capita
income. Poverty is one of the factors correlated directly to a low standard of
education, reliance on traditional healing methods and continued isolation from
the outside world, all of which culminate in a higher likelihood of being unable to
access national healthcare services. In 2003, the aforementioned rural–urban
migration pattern was studied relative to the incidence of poverty in Nepal,
although unfortunately, according to Oucho (2002), it is more usual for experts
on migration and poverty to work independently, normally not considering the
effects of demographic factors on poverty and vice versa (Ad Hoc, 2003).
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Table 1.1: Migration patterns in Nepal relative to incidence of poverty (Adapted from Ad Hoc, 2003).
Ecological Zone Incidence of Poverty (%) Poverty-gap Index Net Migration
Mountain 56 0.185 -14.8
Hill 41 0.136 -48.0
Terai 42 0.099 62.8
Urban Kathmandu 4 0.004 N/A
The link between poverty and migration away from rural areas in mountainous
and hilly ecological zones is clear, with net migrations of -14.8 and -48.0 from
mountainous and hilly areas, respectively (Table 1.1). It is evident that changes
must be made if poverty is to be reduced and fewer individuals are to migrate to
urban areas. Declining agricultural productivity and environmental degradation
in parts of the Himalayas have also encouraged men and often even women to
engage in short-term migration (Centre for Women and Development, 1988).
Life expectancies in the Himalaya are show in Table 1.2.
Table 1.2: Average life expectancy of people living in the Himalayan region (life
expectancies from the United Nations except Tibetan Autonomous Region from People’s Republic of China national statistics).
Country Afghanistan Pakistan India Nepal Bhutan TAR
Life Expectancy (years) 44.64 65.5 64.7 63.8 66.13 67
The Himalayan region is not far below the global average of 67.2 years as all
nations except for Afghanistan have life expectancies in the mid-60s. Although
not far off the global average, Pakistan, India and Nepal rank 136th, 139th and
143rd respectively, among the 195 recorded nations, showing significantly higher
mortality than western countries at a younger age. Whilst the region may not be
able to develop sufficiently in the near future to rival many developed nations for
poverty alleviation, there is a direct link between poverty, healthcare and life-
expectancy which cannot be ignored. Improving land use and productivity is key
to improving living standards and the population’s health. Improvements in the
quality of subsistence living, and education to show the potential benefits of
selling crops or livestock, provide obvious theoretical and developmental
solutions to the problem of poor living standards.
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1.4 Current agriculture and productivity
Geographical constraints often restrict the flow of goods to and from isolated
areas; landslides, mudfalls and soil degradation not only adversely affect crop
yields and farming practices but also restrict transport and the advantages it
brings.
Climatic conditions vary significantly depending on latitude and altitude. The
consequences of this are manifested in a rich diversity of living conditions,
farming practices and the species or landrace cultivated. A huge range of
traditional crops are grown in the Himalaya and, more particularly, in the Central
Himalaya. Over 40 species of food grains are grown in traditional
agroecosystems which have been managed by local farming communities since
time immemorial. These traditional crop varieties have evolved over centuries
and are well adapted to the region. A number of edaphic, topographic and
climatic factors associated with different selection pressures over centuries of
cultivation have resulted in immense variation in the crop species present
(Maikhuri et al., 1996). Having such a wide range of crops available is beneficial
for the introduction of agroforestry (AF) to specific areas, although their
specificity of growth responses under particular conditions may be a drawback.
More widely recognised species with the C4 carbon fixation pathways and low
oxygen tolerances often found at altitude and throughout the mid-hills include
maize (Fig. 1.3), sugarcane and millet. Table 1.3 shows the huge diversity of
different species found in the Himalayan region alongside a global comparison.
As would be expected, many of these species are endemic to the region, having
evolved under specific and discrete conditions.
Table 1.3: Diversity of Himalayan species compared with global estimations. Figures in parenthesis represent the number of endemic species. (Adapted from
Singh and Hajra, 1996).
Total number of species Himalayan Region World
Angiosperm 8000 (3200) 250000
Gymnosperm 44 (7) 600
Pteridophytes 600 (150) 12000
Liverworts 500 (115) 8500
Mosses 1237 (450) 8000
Lichens 1159 (130) 20000
Fungi 6900 (1890) 120000
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C3 crops, which are widely grown in Europe and other temperate and tropical
climates throughout the world, are often equally capable of being grown at mid-
altitudes in the Himalaya. Although the extreme topographic gradients
experienced within the Himalaya might be seen as a drawback in terms of the
sheer range of climatic conditions, this provides terrain suitable for a very wide
range of species. Selection of appropriate species is important in designing
effective AF systems as a number of factors must be taken into consideration,
such as quantifying how difficult local farmers will find it to grow individual
species and whether their introduction is sustainable with respect to local
nutritional and physiological needs. These issues are explored in greater detail in
later sections. When explored at a detailed regional level, the Himalayan climate
and geography can be seen to be constantly changing over time, with
fluctuations in land, nutrient and water availability. Figure 1.3 shows an
example of a C4 crop, maize, being used for subsistence production of flour to
make bread products.
Figure 1.3: A Tamang women in her home in the Nepal mid-hills with cropped maize, being prepared for corn flour production.
Climate change is undoubtedly a factor contributing to many facets of the
region’s difficult-to-predict geophysical transformations and is examined further
in Chapter 2. These changes make it difficult to implement effective land-use
strategies, as certain conditions may lead to alterations in nutrient/hydrological
[16]
cycles or land degradation, which are arduous to predict and rely on complex
models requiring large quantities of meta-data.
Land degradation is a major issue facing much of the Himalaya and is directly
affected by land use. Empirical evidence from Jammu and Kashmir in the
western Himalayan region shows that 73% of the state suffers from severe land
degradation (Singh, 1998), although the entire region from the high mountain
areas through to the Terai is highly susceptible. Figure 1.4 shows mild soil
erosion in the Nepal mid-hills, resulting in concentrated water channels and
depletion of soil fertility.
Figure 1.4: Soil erosion in Kaule, Nepal. (http://en.kauleev.org, cf. W3)
To provide context, Singh et al. (1998), stated that “developmental activities are
increasing rapidly to support the tourism infrastructure whilst there is an
uncertain correlation between anthropogenic activities in the mountains and
hazards in the plains such as floods. Owing to a lack of basic research, there is
little effective information which can be used for long-term effective monitoring
of ecological and hydrological responses to global change.”
Issues surrounding land ownership
Fortunately, the majority of the region’s land ownership is determined through
various traditional hierarchical systems, but unfortunately, population densities
are becoming a problem, particularly in Nepal and Bhutan (Karan and Iijima,
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1985); as sons inherit family land and start their own families, the decreasing
mortality rates within communities sees land becoming increasingly divided,
thus giving increased individual ownership but with each owning a smaller area
of land. The result is a plot with less agricultural and economic value, leading to
an increased proportion of owners selling their plots to facilitate migration to an
urban surrounding.
One approach to combating this trend is community land ownership, permitting
joint ownership and responsibility for multiple families’ land in order to increase
living standards. This may simply be through joint farming of agricultural land to
assure a fairer distribution of crop products or may result from a multi-faceted
agroforestry approach to improve various factors affecting lifestyle. The practice
of community forestry in Nepal has led to extensive restoration of degraded
forests and strengthening of local peoples’ livelihood – although the community
forestry approach is currently largely confined to state forests and adjoining
communities.
Standard community forestry programmes have provided evidence that people
could be excluded from the process of forest management either because of
spatial distance to the forest or social distance from its owners. People residing
far from state forests without access to community forest land are a cause for
concern. For example, a large population in the Terai has unavoidably been
excluded from forest land tenure, although recent initiatives to promote
agroforestry in fallow and public land in the Terai have created new land tenure
opportunities for excluded people whereby management rights of the public land
are being transferred to poor families through long-term lease agreements.
Trees are planted on public land to generate a forest resource with income to
share between users and respective land providers such as local government
bodies. Cash crops are also grown in individually divided plots, further benefiting
each family financially (Shrestha and Dhillion, 2006). Such models demonstrate
the potential of agroforestry not only to increase sustainability and living
standards, but also to provide a social means of alleviating population stress.
Land is often divided by seemingly undistinguished boundaries, agreed within
and between families and communities. Nomadic peoples have a restricted legal
status when working land, although there have been few incidents in recent
history of conflict between governments and nomads. The most notable conflict
leading to widespread systematic reform in this regard must be the “profound
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changes in the last four decades, with China greatly affecting the traditional
Tibetan pastoral production systems [across the Tibetan Plateau]” (Ning and
Richard, 1999).
Adoption of a single, ubiquitous method of farming throughout the Himalaya
would be impossible, as the edaphic, topographic and climatic factors vary so
greatly and lead to a multitude of crops being grown using varying techniques
and for different purposes. Land is normally owned by individual families and
passed down generations, often with no legal security, with sons gaining primary
ownership ahead of their spouse. In the majority of Himalayan communities, the
farming is viewed predominantly as an inferior role suitable for women, thus
creating a paradox between males gaining both socio-economic value and
sustenance from the land whilst responsibility for this rests with the women.
Such a contentious issue must be handled with sensitivity when bringing about
changes to a community, especially if cash crops or livestock are being
introduced for economic gain. Many observers have made note of this
sociological issue, an example of which is shown in Figure 1.5.
“This is the problem of women [in the Himalaya]: their subservient position and
forced inclusion into the capitalist system of labour-first by their own men due to
the patriarchal division of labour, which turns partners and co-workers into
master and servant; then by the male elite of the village, who maintain and
confirm this division; then by bureaucrats and corporate power-holders of the
global market economy into which the women are inserted, without their
knowledge, consent, or control.”
Figure 1.5: Azhar-Hewitt’s (1999) observation of the potential difficulties faced
with a neoliberal free-market, capitalist system evolving in the region.
The conflict between subsistence needs and commercial interests can be seen in
many situations and locations throughout the region, such as along the “fruit-
belt” of the Mussoorie-Chamba road in the Indian district of Tehri Garhwal,
where the privatisation of traditionally common property land has led to
“commoditisation of local activities, use of migrant labour and distinct changes
to working relationships” (UNPAN, 2008).
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Current Farming Practices
Many crop types are grown throughout the Himalayan region. Altitude is the
empirical factor dictating climatic and environmental conditions, allowing certain
species to be grown using specific techniques.
Pesticides have become widely used across the region, although generally in
small quantities. In some modern agroecosystems, new crops requiring high
energy and monetary input were also associated with increased human labour,
forest resources and chemical fertilizer and pesticides use. Energy projection for
farmyard manure in traditional crop cultivation has been found to be 80 – 90%
of the total energy cost, thus traditional crop cultivation has been cited as more
efficient in energy and economics (Nautiyal et al., 2007). Many communities
utilise human and animal waste as a source of organic material, although lack of
infrastructure and organisation within communities often results in most waste
remaining uncollected. Application of manure is useful in developing Himalayan
countries as the supply is plentiful and self-sustaining and it contains a high
proportion of organic matter, which is beneficial for many crop species. An
incomplete understanding of the potential benefits of applying manure is due, in
part, to ineffective local education and few demonstrative governmental or NGO
initiatives. Agroforestry systems can enable communities to collect, manage and
monitor human and animal waste to maximise the efficiency with which it is
used. Further information is given in Chapter 4.
Both organic and inorganic pesticides are applied to agricultural land throughout
the region and are widely available, with 55 registered importers and 3450
resellers (2543 licensed) in Nepal alone, marketing 73 registered common
pesticides under 342 trade names (Koirala et al., 2009). In Nepal, nine major
pesticide groups involving seven subgroups of insecticides were imported
between 1997 and 2003 and pesticide use amounted to 142 g ha-1, which is low
compared to other counties (Diwakar et al., 2008). The high cost of purchasing
imported agrochemicals relative to the low incomes of rural communities is one
of the main reasons for such low levels of application.
With the region having been bypassed by the so-called ‘Green Revolution’ in the
1960’s, mechanised farming methods involving widespread, calculated pesticide
application have only gradually begun to be used in certain areas, where
companies own and profit directly from increased yields. Peasant farmers often
use crude, non-specific pesticides such as urea; an advantage to this being is its
direct availability from animal waste.
[20]
Understanding of the biological pathways and effects of pesticides across the
region is incomplete, and this, coupled with eroded soil and high rainfall during
the monsoon season, results in widespread leaching of pesticides and nutrients.
Many studies have investigated contaminant and pollutant levels in remote areas
(Li et al., 2006) and one found that polychlorinated biphenyl (PCBs, a ‘persistent
organic pollutant’ whose production was banned by the United States Congress
in 1979 and the Stockholm Convention on Persistent Organic Pollutants in 2001)
reached concentrations in Himalayan lakes comparable to industrialised areas,
despite their remote and seemingly pristine location (Galassi et al., 1997).
Educating farmers regarding methods of reducing land degradation and run-off
as well as the positive and negative attributes of pesticide and insecticide
application is essential to achieve maximum crop growth and yield and reduce
environmental impact.
Irrigation is applied by some communities, depending on the crops grown and
general infrastructure of the area. Himalayan water supplies often run through
semi-legitimate piping from water sources to the surrounding area with little or
no government regulation and are used for all purposes, be they agricultural
processes or drinking water. It is common for mid-hill communities to have
communal paddy fields, which are worked collectively at the appropriate time of
year (before and during the monsoon season), with the yield shared (Schroeder,
1985). There is also evidence that irrigation of agroforestry systems in the
Himalaya can be highly beneficial. For example, in the Indian Garhwal Himalaya,
the total cost of establishing an irrigated agroforestry system was 1.23 fold that
of the unirrigated one, whereas the total benefit was 209-fold (Maikhuri et al.,
1997).
An overall perspective of cropping intensity can be drawn by dividing the gross
cropped area by the net area available within a specific farming area to obtain a
Cropping Intensity Index (CII). Gosain (2009) calculated the CII for 300 land-
holders in the sub-Himalayan Terai and the Indo-Gangetic plain in the Indian
state of Haryana. The analysis showed that, of the 300 respondents, 16.3% had
low CII values, 21.6% had high values and the majority (62%) had an
intermediate CII. Much of the agricultural Himalaya has low to medium CII, as
most land-owners cannot achieve consistently high yields owing to the relatively
high economic and mechanised inputs required.
[21]
Current research in the Himalaya
The Himalayan region is seen by many as an opportunity to demonstrate
responsible agricultural development through basic, unilateral, common-sense
decisions alongside progressive technologies and a contemporary understanding
of the need for a holistic approach to scientific study and the effect on people’s
livelihoods. In recent times and with mainstream consciousness of
environmental change increasing, more detailed research that stands up to
scrutiny has been undertaken across the region, predominantly by NGOs. For
example, the mission statement of the Resources Himalaya Foundation defines
its work as “a promoter of ‘good science’ to facilitate ‘politically correct’ decisions
so that biodiversity conservation in the Himalaya is secured and benefits of
conservation practices accrue to the poorest segment”
(www.resourceshimalaya.org, cf. W4). The Himalayan Research and Cultural
Foundation works in conjunction with the United Nations Economic and Social
Council to support “scientific appraisals of the issues confronting the Himalayan
and adjoining regions to make specific policy-oriented studies and need-based
recommendations as the means to promote the human, educational and
economic advancement of the peoples besides preserving and enriching their
ethno-cultural, literary and historical heritage” (www.un.org/en/ecosoc, cf. W5).
A glossary of key organisations is given in Chapter 7.
The recent media hysteria surrounding possible inaccuracies in the
Intergovernmental Panel on Climate Change (IPCC) 2007 Assessment of Climate
Impacts, and especially the predicted date for the disappearance of the
Himalayan glaciers, demonstrates how easily the underpinning and pressing
issue of climate change can be overshadowed, and the numerous adverse direct
and indirect implications ignored. Whilst these impact on a global scale, the
report also serves to highlight the vulnerability of the Himalaya and the
potentially detrimental changes facing its people which must be addressed.
[22]
Chapter 2: Issues and challenges
2.1 Climate change
The issue of climate change is relentlessly reported by the world-wide media,
with varying representation of the scientific facts. In its simplest form, climate
change can be described as an alteration or variation in the world’s climate (Dow
and Downing, 2007). The term ‘climate change’ has become synonymous with
anthropogenic activity and this is now a connotation generally accepted in both
the scientific and wider global community. Climate change in IPCC usage refers
to identifiable changes in the state of the climate (e.g. using statistical tests)
from the mean value and/or the variability in its properties which persist for an
extended period, typically decades or longer (IPCC, 2007). Primarily contributed
to by combustion of fossil fuels and the rearing of cattle and other ruminant
animals, atmospheric concentrations of carbon dioxide (Fig. 2.1) and other
greenhouse gases (GHGs) such as water vapour, nitrous oxide and methane,
have increased exponentially in modern history, leading to the so-called
‘greenhouse gas effect’ whereby excessive GHG levels in the atmosphere absorb
more solar radiation, causing a subsequent rise in global temperatures (Fig.
2.2).
The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment
Report (2007) states that “warming of the climate system is unequivocal, as is
now evident from observations of increases in global average air and ocean
temperatures, widespread melting of snow and ice and rising global average sea
level” and is now becoming better understood due to “numerous datasets and
data analyses, broader geographical coverage, better understanding of
uncertainties and a wider variety of measurements.”
The Himalayan region, including the Tibetan Plateau, has shown consistent
warming trends during the past 100 years (Yao et al., 2006), the effects of
which are numerous, interlinked and often subtle. Most dramatically, the
aforementioned receding of the Himalayan glaciers will have widespread
detrimental effects with regard to the regional hydrological cycle and water and
food availability. Monsoons have been weakening, with the number of days of
rainfall decreasing, whereas the number of high intensity rainfall days has
increased (Ramanathan et al., 2008), causing crops to produce significantly
reduced yields, or fail altogether. Many of the native people working the land
rely on an understanding of the seasons, passed down through the generations,
which is now at odds with present day conditions.
[23]
Figure 2.1: The rise in global carbon dioxide emissions since 1940 and the predicted level of stabilisation, depending on future emission levels. (Adapted from IPCC, AR4, 2007)
Figure 2.2: The exponential rise in global temperatures, following the industrial revolution. (http://www.iloveco2.org, cf. W6)
2.2 Water availability
Vast quantities of water originate in the Himalaya and supply over half a billion
people, approximately 8% of the global population, with water resources (IPCC,
2007). The availability and flow of water in the Himalaya is directly related to
climate change and anthropogenic activities; land use and distribution of water
is influenced and dictated largely by humans. A substantial body of academic
[24]
work has been published regarding the subject. Mitigation and adaption are the
two possible routes to help overcome water stress in the region (these are
explored in detail in Chapter 5), although there is a high degree of confidence
that neither of these alone can avoid all climate change impacts (IPCC, 2007).
Himalayan glaciers cover a huge geographic area and have enormous
importance as the starting point of multiple water sources. Despite this, glaciers
in the Himalaya are receding faster than in any other part of the world (IPCC,
2007). A demonstration of this is the finding that 466 glaciers in the Chenab,
Parbati and Baspa basins lost 21% of their area between 1962 and 2001/2004
(Kulkarni et al., 2007). Increasing global temperatures and atmospheric CO2
concentrations will only drive this trend, as climate empirically controls river flow
and glacier mass balance (Sharma et al., 2009). Glaciers play an important role
in maintaining ecosystem stability as they act as buffers and regulate the
quantity of water supplied as runoff from high mountains to the plains during
both dry and wet periods (UNPAN, 2008).
Effects of extremes of weather, such as flooding in Bangladesh and drought in
northern India, are closely associated with climate change and are directly
affected by recent changes in water flow throughout the Himalaya. Floods in
Bangladesh have been devastating and widespread for much of the past twenty
years, with aid donors stimulating discussion to address the chronic flood
disaster problem after the 1987 floods.
The United Nations Development Program (UNDP) has funded upstream water
storage in the Himalaya, basin storage on floodplains and draw-down of ground
water beneath flood plains (Brammer, 1990) ever since, but with little success.
Over-simplifying the issue may to be blame for this, as three landmark
publications concerning the hydrology of Himalayan mountains (Bruijnzeel and
Bremmer, 1989; Alford and Occas, 1992; Bandopadhyay and Gyawali, 1994)
have made it amply clear that the hydrological research conducted in this region
so far is inadequate (‘the so-called black-box’) to substantiate the commonly
held notion that deforestation and other anthropogenic activities by the
mountain inhabitants are the direct cause of floods and associated damage in
the adjacent plains (Negi, 2002). The naturally low land elevation of Bangladesh
and its geographic location cause inherent susceptibility to environmental
problems although these are made worse by climate change and population
stress. Citizens of the country and surrounding areas maintain a lifestyle based
around the presence of water. Indeed, Stone (1992) referred to South Asian
[25]
civilisation as a ‘hydraulic society’. Water availability is inherently linked with
food security for millions of people relying on a subsistence lifestyle, increasing
the human cost of water flow problems and the urgency with which these must
be addressed.
Water supplies to the Ganges by its tributaries have dwindled in recent years
(Nishat and Faisal, 2000), leading to uncertain water distribution across much of
India. Simultaneously, on the north-eastern plain of the mountain range, under
Chinese rule, the Himalayan-fed Salween, Mekong (which runs south into Laos
through a series of controversial dams) and Yangtze rivers are suffering from
the worst drought in 50 years, with the Mekong at half its normal flow rate in
March 2010 (Delgado et al., 2010). The Chinese government is in the process of
erecting a series of dams on many of the rivers sourced in the Himalayas. Here,
another paradox arises as policy-makers strive to attain renewable energy
targets, whilst simultaneously adversely affecting regional biodiversity by
destroying natural habitats and initiating numerous unpredictable knock-on
effects around the Asian region (Bagla, 2006; Bawa et al., 2010; Chaplin, 2005).
Figure 2.3: Proportion of China’s energy production obtained from various sources during the past 40 years. (International Development Agency, www.iea.org, cf. W7)
[26]
Having developed hydro-electric power supplies over the past 40 years, Figure
2.3 shows how China is currently producing vast amounts of energy, more than
ever before, from renewable sources.
Mitigation and adaption techniques must be used across the region if
unequivocally vital water supplies are to be maintained and monitored
successfully. Techniques used within agroforestry systems may be of benefit in
this regard. As Bruijnzeel and Bremmer (1989) ask, ‘what downstream benefits
can reasonably be expected in regard from upland reforestation?’ Furthermore,
how can agroforestry be beneficial for soil stability and water flow?
2.3 Indigenous culture and religion
The peoples of the region are numerous and diverse and among those living
below the poverty line, nomadic or subsistence lifestyles are common (Bose,
1976). Around 50 discrete groups inhabit the region, each with its own cultures,
traditions and customs, although the differences between groups and possible
overlap between each varies significantly, reflecting the complexities of the
region. Whilst there is enormous ethnic diversity, this is distinguished by a
limited set of ethnic contrasts, such as: Hindu vs. Buddhist, tribe vs. caste, and
mountain vs. middle hill vs. lowland Terai (Levine, 1987). The most recent
censuses of Nepal (2001) and Bhutan (2005) show Hindu / Buddhist ratios of
80.6 / 22.1% and 10.7 / 75.3% respectively, although in reality many practice a
combination of both religions, together with local shamanic rituals. Islam,
Christianity and Kirat (an indigenous religion with Hindu influence), amongst
others, have followers throughout the Himalaya, but to a much lesser degree
than Hinduism and Buddhism. Overall, the diversity and complexities of religious
groups parallel the physical aspect of the terrain. Stone (1992) concluded that
the Himalayan region is characterised “not only by ecological fragility but also by
a deep and historical geopolitical sensitivity.”
Many of these groups are intertwined in their beliefs and hierarchical systems,
through caste, tribe, religious belief or location. As Hindus consider cows to be
sacred, believing they represent a symbol of unselfish giving (Teece, 2004),
many abstain from eating beef. The practice of ahimsā is often followed in rural
areas, and, coupled with Buddhist beliefs, means that vegetarianism is relatively
widespread. When introducing new farming techniques to these people’s lives, it
is imperative to understand potential compromises that may have to be made.
[27]
This is especially prevalent when considering the implementation of agroforestry,
as raising livestock may only be possible with certain animals. Buffalo (a
straightforward alternative to cattle), goat and chicken are meats widely eaten
throughout the Himalaya (Devendra, 1987).
[28]
Chapter 3: Sustainable agriculture and development
Sustainable agriculture
Placing emphasis on creating sustainability in agriculture, per se, is a relatively
modern phenomenon. Only since realising that sustainable systems may play an
important role alongside, for example, high input, intensively farmed
monocrops, have mindsets altered and policy changed in an attempt to actively
employ such systems in various locations around the globe. The benefits of
farming within one’s needs are most apparent in poor parts of the world where
people must rely on agricultural success for food and materials to support basic
amenities. Modern terminology came to fruition in the early 1980s with the
emergence of the “concepts of regenerative agriculture” (Rodale, 1983) and the
articulation of “sustainable agriculture” (Jackson, 1980). This early concept has
evolved into a “construct of agriculture based on principles of ecological
interaction” and is now referred to as “an ecological definition of sustainability”
(Harwood, 1990).
Prior to the ‘Green Revolution’ fifty years ago, farming was carried out largely for
subsistence throughout the world. The exponential increase in food production in
the latter half of the twentieth century resulted primarily from new technologies.
The introduction of new farm machinery, agrochemicals to control weeds and
plants, improved plant breeding techniques and inorganic fertilisers (Filson,
2004) has led to much of the developed world growing specialised plant
varieties, specifically bred to produce high yields in specific environments, but
generally requiring high inputs. Fifty years later, there is sound ecological
evidence to support alternatives to this now ‘conventional’ farming technique
and it could be said that many technologies were applied without a full
understanding of possible repercussions such as soil degradation, acidification
and salinisation (Mason, 2003) and loss of natural habitats for many species
(Filson, 2004). Soil organic carbon and nitrogen levels have also been widely
depleted by modern farming (Fig. 3.1). Priorities are now being reassessed,
such as the importance of soil ‘health’ and nutrient availability. The concept of a
soil-plant-air continuum (SPAC) is now appreciated as an effective method of
approaching plant physiology and the potential effects incurred in agriculture
(Jeffrey, 1987).
[29]
Figure 3.1: Depletion of soil organic carbon and nitrogen during the past 50
years and estimates of the potential benefits of ‘alternative’ practices. (Adapted from Tilman, 1998).
The Himalayan region has predominantly been bypassed by the mechanisation
of agriculture due to its isolation and lack of wealth. Not only is financial backing
required for such drastic changes but also sufficient infrastructure to support
consistent transport links and the mass migration of labourers. Recent changes
have, however, included limited use of agrochemicals as discussed in Chapter 1.
The economic limitations of the region serve to demonstrate the innate
interconnectivity between sustainable agriculture and sustainable development.
Sustainable agriculture can be viewed from a number of perspectives i.e.
holistically, systematically and industrially. It should be noted that, whilst
methods or components taken from industrialised systems may be of use in a
small-scale sustainable system, “farmers with different philosophies may choose
to integrate the same basic components quite differently” (Ikerd, 1993) and so
many scientists see comparisons of conventional and sustainable systems as
unscientific (Council of Agricultural Science and Technology, 2000). Ikerd (1993)
defined sustainable agriculture as being “based on a holistic paradigm or model
of development which views production units as organisms that consist of many
interrelated suborganisms, all of which have distinct physical, biological and
social limits.”
Corselius et al (2001) went further by comprehensively describing sustainable
agriculture as the production of “food and fibre” in ways which:
[30]
1. Improve the underlying productivity of natural resources and cropping
systems so farmers can meet increasing demand associated with population and
economic growth;
2. Produce food which is safe, wholesome and nutritious and promotes human
well-being;
3. Ensure an adequate net farm income to support an acceptable standard of
living for farmers while underwriting annual investments needed to improve the
productivity of soil, water and other resources;
4. Comply with community norms and meet social expectations.
Crucially, all of these descriptions encompass and embrace sensitivity to the
environment, social strata and economy.
Development and tourism
Before the progression towards “modern mass tourism” (Spaltenberger, 2005) in
the Himalaya, particularly in Nepal and north-east India, sustainable
development could be defined as “development that meets the needs of the
present without compromising the ability of future generations to meet their own
needs” (World Commission on Environment and Development, 1987). In Nepal,
tourism accounts for 10% of the gross domestic product (GDP) and is the single-
most important source of foreign currency (The World Bank, 2002). In India,
tourism is the second-largest source of foreign currency behind the gem and
jewellery business (Trade and Environment Database). Western and Indian
tourists flock to the Himalayas and wealth from this source has a potentially
huge impact on millions of rural people. Mountaineers, trekkers and pilgrims all
contribute to funding the Himalayan economy, but the money spent by tourists
has diverse effects on local economies. Tourist income stimulates the economy
and induces the so-called “multiplier-effect” whereby jobs are created, capital is
accumulated and local workers who previously depended on subsistence farming
start their own businesses to serve tourists, such as selling or renting supplies,
providing guides or selling souvenirs. These businesses, in turn, employ people
as guides or workers, who thereby benefit indirectly from tourist income (Trade
and Environment Database). Part of the tourist income may also be used to
improve local living standards through improved health care, education and
buildings (Spaltenberger, 2005). Responsible policy-making and fair distribution
of wealth should be at the forefront of government strategy, ensuring money is
spent productively and maintains the multi-faceted attraction of the region.
[31]
Nowadays, the components of sustainable development are adapted to account
for sustainable practices which encompass tourism development. According to
Burns and Holden (1995), “the guiding principles for sustainable development of
tourism are as follows:
1. The environment has an intrinsic value that outweighs its value as a tourism
asset. Its enjoyment by future generations and its long-term survival must not
be prejudiced by short-term considerations;
2. Tourism should be recognised as a positive activity with the potential to
benefit the community and location, as well as the visitor;
3. The relationship between tourism and the environment must be managed so
that environmental sustainability is assured. Tourism must not be allowed to
damage the resource, prejudice its future enjoyment or bring unacceptable
impacts;
4. Tourism activities and developments should respect the scale, nature and
character of the place in which they are sited;
5. In any location, harmony must be sought between the needs of the visitor,
location and host community.”
[32]
Chapter 4: Agroforestry
The concept of agroforestry (AF) as a land-use system, like all forms of
sustainable agriculture, is a contemporary idea that first emerged in the 1970s
(Sanchez, 1996), although there are numerous examples of age-old systems
which draw on various aspects of AF and have been in use since long before the
phrase was coined (Singh et al., 1989). The term is generally recognised as
involving the growth of woody perennials alongside pasture or crop species
(Azim-Ali and Squire, 2002) and there is evidence of beneficial effects on carbon
sequestration, biodiversity conservation, soil enrichment and air and water
quality within at least some AF systems (Shibu, 2009). Whilst the backbone of
agroforestry lies in the combination of species grown, it should not simply be
viewed as a restrictive set of guidelines or farming practices; holistic thinking
about the interconnectivity of various biological units (soil, plants, animals and
atmosphere) and the overall impact of each element on lifestyle, sustainability
and environment is key to producing a flexible, multifunctional, working
landscape. Plant and animal components are therefore only of equal importance
to environmental components such as climate, topography and soil. Variation in
all of these individual components gives rise to the possibility of hundreds, or
even thousands, of agroforestry systems (Young, 1989).
Combe (1982) summarised this when he stated that “agroforestry designates
land management techniques, which implies the combination of forest trees with
crops, or with domestic animals, or both”, and went on to explain how “because
of their interdisciplinary character, they are of particular interest for many
countries of the Third World, where an equilibrated development of all rural
lands must be obtained”. The flexible nature of AF systems is entirely compatible
with the Himalayan region, where the environment is as varied as the diverse
flora and fauna. Many localities use farming techniques evolved over decades or
centuries of isolation and consequently harvest many different types of plant for
differing purposes; thus, approximately 40 main species of grain crop are grown
in Central Himalaya alone. Such independence and digression from
‘conventional’ harvesting of high-yield, high-input crop plants makes the region
appropriate for the development of new AF systems which combine the rich
cultural, social and environmental diversity with new technologies and education
regarding the potential benefits.
Improvement of rural people’s lifestyle and livelihoods must be seen a key aim
when introducing agroforestry within a community, as this serves not only to
[33]
increase living standards but should also motivate land-owners to continue with
changes and play a proactive role in the management of land and community.
Figure 4.1 demonstrates how the environmental and economic benefits of
agroforestry can motivate entire communities to switch from conventional
techniques.
“Only one farmer, Jush Ram Tamang, and his family changed to AF and stayed
with it until they became self-sufficient. The family has been using AF since then
and their income is now clearly above their neighbours’ who still continue to
make a living from using traditional farming methods. The income generated
through AF allows Jush’s family not only to cater for their needs and feed their
livestock, it also covers [the cost of] the university degree of their eldest
daughter. Nowadays, Jush Ram Tamang’s neighbours are highly motivated to
change to AF, a method which he has implemented since 1994. At present,
fifteen farmers are committed to take part in the project.”
Figure 4.1: Observation of one farmer’s increased income, which in turn encouraged other community members to join an agroforestry systems approach in Nepal. (http://en.kauleev.org, cf. W8)
Not only can AF include the use of native species, many of which may be totemic
to locals, but it may also allow them to be grown alongside new species which
help sustain the environment, although examples from around the world show
that this is not always straightforward. Langenberger et al. (2009) evaluated the
utilisation of plant resources by Philippine farmers in order to identify native
species suitable for integration into agroforestry systems. The farmers reported
using 122 plant species for 77 purposes; however, few species could be
recommended for adoption into AF systems due to the lack of well-developed
markets for most species (Jose, 2009). There are also many examples of
agroforestry systems adopting locally grown species (Dhyani and Tripathi, 1998;
Singh et al., 2007).
AF can vastly improve a number of environmental factors, many of which, in
turn, help create sustainability both within the system itself and the surrounding
areas. Increased water use efficiency, protection against soil erosion and
leaching, improvement of soil fertility and moisture, restoration of degraded
soils, effective maintenance of watersheds and an increased diversity of habitats
and hence available products are some examples of the potential benefits of AF
[34]
(Reijntjes et al., 1993). The ability to produce and store products essential to a
subsistence living such as food, fuel, building materials and raw material for
production of local crafts to be sold in the tourist trade (Rocheleau et al., 1988)
is thereafter a further benefit to this holistic approach to agriculture and
contributes to an improved financial security.
Encouraging evidence has been seen throughout the Himalayan region,
particularly for enhancing productivity and arresting land degradation. The
concept has become affordable to the poor, especially when compared to
expensive conventional conservation measures (Grewal et al., 1994; Khybri et
al., 1992; Mittal and Singh, 1989). As with any newly introduced land use
strategy, there are initial costs to bear which require capital input. In situations
where communities are entirely unable to provide this, government and NGOs
should work to subsidise the costs or provide loan options. Such support
mechanisms for AF have been widespread across much of the sub-tropics and
Africa (Russell and Franzel, 2004). Processing industries involved in outgrower
schemes for higher-value crops and livestock products, for sale in niche
markets, may also be encouraged to become involved in subsidising AF projects
(Franzel and Scherr, 2001)
As with any farming system, agroforestry has several limitations. The problems
primarily originate from competitive interactions when different plant species are
grown in mixtures, as scarce natural resources such as water, nutrients and light
are not unlimited and must be managed accordingly. A basic level of scientific
knowledge is therefore required for effective land management as all
agroforestry systems are defined by their spatial and temporal arrangement
(canopy cover, root profile, season; Young, 1989) and each species competing
for light, water, nutrients and allelopathy. Understanding the interactions
between various biological processes alongside geographical constraints is vital
to assessing the impact of competition on biodiversity, sustainability and
productivity. These issues are explored in detail in Chapter 5.
Types of agroforestry system
Agroforestry (AF) systems can take my different forms, both spatially and
temporally. Aspects such as planting, harvesting, pruning and rotating crops are
all flexible factors which must be carefully planned to maximise productivity,
resource use and sustainability. The two main timing methods of AF are
simultaneous and sequential systems. Simultaneous systems, as the name
suggests, are the result of the same species’ biophysical interactions over an
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indeterminate period. Simultaneous AF systems are more susceptible to
competition than sequential ones (Sanchez, 1995). Simultaneous AF techniques
such as alley cropping must be carefully managed as the competition factor may
exceed beneficial fertility effects (Sanchez, 1995). Sequential systems may use
techniques such as crop rotation, relay intercropping and improvement of fallows
to minimize competition. However, monitoring growth and development
processes responsible for crop yield increases is often difficult, although new
methodologies for reliably measuring complex below-ground interactions of
sequential systems are currently being researched.
Home gardens may also be used to grow small cash crops which are
physiologically suited to the environment. Simple vegetable plots provide food
for the individual family or community and can be managed systematically. For
example, different community land owners may annually rotate the vegetable
species grown, to provide appropriate biological conditions for maximum
productivity within the community. Garden nurseries provide plants for use
across a wider area at the appropriate time. Not only does this encourage
ongoing application from the land-owners, but also helps to make clear which
species are to be planted a long time in advance.
A typical AF setup may employ some or all of these types of system. For
example, an AF system in the Garhwal Himalaya was measured to be 27.47%
simultaneous, 27.47% sequential, 1.1% home garden and 43.96% village
forestland (Nautiyal et al., 1998).
[36]
Chapter 5: Implementation of agroforestry techniques: potential
benefits and limitations
5.1 Limitations of the Himalayan region
Some environmental factors in the Himalaya are extremely variable across
altitude and latitude, whilst others are relatively constant and dictate the
regional climate. Each factor affects the suitability of an area of land for the
production of food and resources, as well as local prosperity. Rainfall,
evapotranspiration rate, soil properties and the supply of water taking account of
seasonality, must therefore be examined as interconnected factors which dictate
the selection of appropriate crop species.
Rainfall
Precipitation is highly variable throughout the Himalaya, although large-scale
relationships between topography, relief and rainfall have been examined
(Bookhagen and Burbank, 2006) with results showing two distinct precipitation
maxima. The first, outer rainfall peak occurs along the southern margin of the
Lesser Himalaya within a narrow band with a mean elevation (0.9 ± 0.4 km) and
mean relief (1.2 ± 0.2 km). The second, discontinuous, inner band occurs along
the southern flank of the Greater Himalaya (elevation and relief both 2.1 ± 0.3
km; Bookhagen and Burbank, 2006). A detailed map of mean annual rainfall and
land relief is shown in Figure 5.1. The complexity of rainfall patterns within the
Himalayan region therefore presents a serious limitation in terms of generalising
the suitability of various AF systems for particular areas.
Although rainfall in the Himalaya may be sufficient to support livestock and crop
production if distributed evenly throughout the year, the reality of seasonal
fluctuations means the effects of too much or too little water are often apparent.
The predominantly agriculture-based economy alongside a regional hydrology
dominated by monsoons leads to “concerns which are not limited to any
particular basin but exist throughout the region including the downstream
plains” (Sharma et al., 2000). Evidence collated between 1866 and 2006 shows
a significant decline in precipitation during the regional monsoon, in unison with
significant increasing trends in annual temperature (measured in the north-west
Himalaya; Bhutiyani et al., 2010).
The erratic nature of rainfall in the Himalaya (Barros and Lang, 2001), the highly
variable evapotranspiration rates (Lambert and Chitrakar, 1989), and the
uncertain and ever-changing ambient water flow from mountain glaciers
[37]
(Sharma et al., 2009) (due, in part, to an increase in global temperatures; IPCC,
2007), together create a complex hydrological cycle which may limit the growth
or feasibility of various species in different ways. Sharda et al. (2009)
summarised this view by stating that “the water availability to meet the human,
animal and crop requirements varies in different quarters of the year with
inequalities existing in different parts of the watershed.” At a local level rainfall
does not always correlate directly with elevation (Singh et al., 1994) but instead,
a wide range of climatic variables.
Possible methods of improving Himalayan water flow are explored later in this
chapter.
Figure 5.1: (a) monsoon rainfall amounts averaged from January 1998 to December 2005 and (b) 5-km-radius relief calculated from topographic data. (Bookhagen and Burbank, 2006)
Excessive rainfall in certain Himalayan areas is a cause for concern. For
example, Grewal et al. (1990) found that 6 mha (million hectares) of soil in
north-east India was threatened by waterlogging and 4 mha threatened by the
formation of ravines. Flooding is a major issue, particularly in the south-east
Himalaya.
[38]
Landslides caused by excessive rainfall are a major problem throughout much of
the Himalaya as they disrupt essential transport links for the movement of
livestock, food and other resources. Gabet et al. (2004) found that landslides in
the Himalaya were not triggered until more than 860mm of rain had fallen
during the monsoon (Fig. 5.2); sufficient antecedent rainfall is necessary to
bring the soil to field capacity, such that future rainfall may produce positive
pore pressures and trigger landslides (Campbell, 1975; Crozier, 1999; Gabet et
al., 2004). Combating landslides is difficult and closely associated with the
processes of soil degradation and run-off.
Figure 5.2: The shaded area delineates the rainfall values that may trigger landslides (shown by diamonds). Note that there are no failures until a total of 860 mm of rain had fallen and that the daily rainfall threshold decreased with
increasing accumulated rainfall until it reached a minimum of 11 mm (Gabet et al., 2004)
Soil
Soil degradation is widespread in the Himalaya and contributes to many
detrimental consequences. Run-off and deep infiltration into soil increases
leaching of nutrients which, in turn, depletes fertility. Water flow and hence
water availability are also affected. Soil degradation, and methods for combating
this using agroforestry systems, is discussed in Section 4 of this chapter.
The dependence on land resources of traditional subsistence agriculture has
resulted in their depletion, with a consequent decline in productivity and
increased poverty. These factors are made worse by the aforementioned lack of
[39]
proper roads and communication facilities (Ghosh, 2007). Soil fertility is poor
across much of the region (Upadhyay and Singh, 1989; Qadar, 2002) and the
cost of applying organic or synthetic fertilisers is a serious limitation for many
poor Himalayan land-holders. In recent years, soil fertility has been improved in
certain Himalayan communities through various initiatives to introduce
vermicomposting, biocomposting and biofertilisers, helping to rejuvenate soil
health. Further dissemination must be undertaken to promote effective farm
management and increase yields. (Ghosh, 2007)
Economic capital for irrigation and livestock
The cost of new livestock and irrigation is also a drawback when implementing
new farming systems in the Himalaya. Poor land-owners often have no capital to
invest in new technology, indicating the need for a holistic approach which
empowers whole communities initially through grants and aid donation, if
necessary, along with the formation of sustainable and profitable co-operatives
to provide income. The lure of cities and other urban environments may also
divide communities, with rural-urban migration increasing rapidly (Ad Hoc,
2003). Further discussion of this issue was provided in Chapter 1.
5.2 Resource capture by plants
Light interception
Squire (1990) defined light interception as being the difference between solar
radiation impacting on a vegetation canopy and that reaching the soil. However,
canopies also reflect a proportion of the incident radiation to an extent which
depends on canopy properties such as leaf angle, surface characteristics and
moisture content (Ong et al., 2006). Fractional interception (f) provides a fair
comparison of light interception values within a defined geographic region, as
this parameter gives a measure of the proportion of the total available radiation
that is intercepted; f is therefore useful in predicting dry matter production
(Squire, 1990). Mean solar radiation in the Himalayan region varies both
seasonally and according to geographical location, and values range from 11 MJ
m-2 d-1 in cloudy upland areas to 32 MJ m-2 d-1 in lowland Terai (Ramanathan
and Ramana, 2005). The Lesser Himalaya and Indo-Gangetic Plains persistently
experience an ‘Atmospheric Brown Cloud’ (Fig. 5.3) layer resulting primarily
from a build-up of aerosols (Ramanathan and Ramana, 2005) and thick soot and
dust (Chung et al., 2005) in the atmosphere, which trap unusually high
quantities of solar radiation. This region is home to over 500 m inhabitants
[40]
(Ramanathan and Ramana, 2005) and so introducing species capable of
intercepting and converting this high level of radiation efficiently is vital for
resource supply.
Figure 5.3: Satellite image of blanket haze over the Indo-Gangetic Plain, taken on December 2nd, 2009. (Earth Observatory, NASA. www.sciencecodex.com, cf. W9)
f values are affected by each component of a canopy, including developmental
stage, leaf area index (L), water status, height and structure (Ong et al., 2006).
As such, f values show significant seasonal and topographical variation. L is
measured as the green leaf area per unit ground area (Keating and Carberry,
1993). In a hypothetical monocrop, where water is not a limiting factor, f and L
are related by the expression:
f = 1 – exp �−���
where k is the extinction coefficient. Extinction coefficients are generally more
useful in modelling light climates for calculating leaf angle distributions (Jones,
1992), as they provide a measure of the fraction of light absorbed or reflected
per unit depth within a canopy.
Increasing values for L and consequent increases in the extinction coefficients k
increase in fractional interception; k and L values are inherently dependent on
canopy size and leaf distribution. Values for k may be higher where leaves are
less randomly distributed, although overall dry matter production will not
necessarily benefit (Squire, 1990). For any given plant genotype, k is much
more responsive to changes in canopy structure than to variation in growing
[41]
conditions (Ong et al., 2006), emphasising the importance of canopy structure
when introducing new plant species.
Vegetation canopies can be classified in several ways based on the distribution
of leaf angles. The two most extreme forms are the planophile canopy in which
horizontal leaves are most frequent and the erectophile canopy in which vertical
leaves predominate (Turitzin and Drake, 1981). Most monocots have erectophilic
tendencies (Fig. 5.4a), whilst dicots tend to have fewer, broader leaves (Fig.
5.4b). Monocots consequently have much higher maximum L values.
Figure 5.4: Typical canopies created by (a) monocrops of erectophiles and (b)
planophiles. (Murchie, 2008)
Certain plant species grown in the Himalaya which show dramatic morphological
differences between genotypes may also exhibit considerable variation in k
values (Squire, 1990). Figure 5.5 shows two such varieties of rice with differing
leaf morphologies which create alternative canopy structures. The new genotype
(cultivar IR65600-42-5-2) has a more even distribution of irradiance through its
canopy, meaning that the relationship between photosynthetic rate and incident
remains linear, benefiting conversion due to its higher L but lower k values.
[42]
Figure 5.5: Overhead view of two rice cultivars, IR72 and the new genotype,
IR65600-42-5-2. The photographs were taken at noon. (Murchie et al., 2005)
The most important attribute in any analysis of light capture by plants is the
efficiency with which they convert solar energy to biomass in the desired form to
support grain filling etc.; in this instance, this involves achieving the optimum
balance between L and k. A number of implications face subsistence farmers
with regard to optimising the ability of their crops to capture and convert solar
radiation, as shown in Table 5.1. All of these factors are interlinked; for
example, high nitrogen supplies significantly increase leaf area index (Green,
1987).
Table 5.1: Factors to be considered when managing crop canopies. (Adapted from Murchie, 2008).
Rate of Canopy Expansion Farming Considerations
Planting density Sowing rate, crop establishment
Leaf number Temperature, species
Leaf expansion rate Temperature, turgor, species
Leaf orientation Species, water stress
Nutrition Macro- and micro- nutrients
Competition Pesticides, herbicides, other species
As agroforestry inevitably involves mixes of woody species and crops, extensive
horizontal and vertical variation in canopy structure is likely. Calculations of
fractional interception are therefore difficult, as the equation assumes a
homogeneous and random distribution of leaves, whereas in reality, there is
substantial spatial variation of light distribution. Nevertheless, the equation itself
and the principles governing it are still necessary to understand light capture by
plants.
[43]
The development and longevity of a foliage canopy is of utmost importance as
this provides a measure of its long-term sustainability. In this respect, mixed
cropping can be highly beneficial as both seasonal and annual values for
fractional interception (f) are smallest for short-duration crops such as cereals
including millet, which is already grown in the Himalaya, and largest for
perennial species when averaged over the entire life cycle (Squire, 1990).
Combinations of crop throughout the annual cycle can also be ‘timed’ by season,
as seasonal f values are greater in long duration than short duration cultivars
(Ong et al., 1996). This principle is known as temporal complementarily (Ong et
al., 1996) and allows intercrops to provide a greater cumulative fractional
interception than either component alone.
Careful planning and management is needed to ensure a net gain in light
capture. As is clearly visible in Figure 5.6, agroforestry systems may appear
disorganised and chaotic to traditional land-bearers. This demonstrates how
farmers must understand the ecological reasoning behind the introduction of a
new system in order to support its implementation.
Figure 5.6: The foliage canopy of a functioning agroforestry system in the Nepal mid-hills, showing variety in plant species, height, structure and leaf orientation.
Plants grown include banana, hemp, maize, millet and nitrogen-fixing grasses.
Light conversion
The production of dry matter is linearly related to the quantity of solar radiation
intercepted by plants when there are no other limiting factors (Squire, 1990;
Monteith, 1981). It could be said that integration from leaf to canopy scale
produces a generally linear relationship between biomass and photosynthetically
[44]
active radiation (PAR), and so a constant conversion coefficient for each species,
with units of g MJ-1 PAR (Ong et al., 1996), can be formulated. Monteith (1981)
researched the conversion coefficients for a number of species, some of which
are compared in Figure 5.7.
Figure 5.7: Relationship between dry matter production and total intercepted radiation for sugar beet, potatoes, barley and apples; the conversion coefficient for each species may be calculated from the slope of the regression. (Adapted
from Monteith, 1981)
Whilst photorespiration contributes to the loss of some carbon, this is a tiny
proportion of total assimilation, leading to the overall conclusion that dry matter
production is proportional to mean canopy photosynthetic rate (Squire, 1990).
Plants using the C4 pathway convert solar radiation to dry matter more
efficiently than those with the C3 pathway (Ong et al., 1996; Fig 5.8), with C4
crops maintaining a higher conversion coefficient during vegetative growth than
C3 crops. Mean values for this growth stage are 4.2 g MJ-1 PAR for C4 crops and
2.5 g MJ-1 PAR for C3 crops.
Figure 5.8: Mean conversion coefficients for C4 and C3 plants during vegetative
growth. (Adapted from Monteith, 1981).
[45]
Where there are no other limiting factors, the expression:
W = εS ∫ fS0 dt
defines the production of dry matter, where εS is the conversion coefficient, f is
the fractional interception, S0 is irradiance (per unit time, dt) (Murchie, 2008).
Stress adversely affects biomass production by inhibiting photosynthesis in a
variety of ways. Extremes of salinity, drought and temperature are inhibitory, as
is exposure to unusually high levels of solar irradiance (Ong et al., 1996). This
photoinhibition specifically damages photosystem II at a rate exceeding that of
simultaneous repair (Ong et al., 1996).
Understanding the physiological differences between C3 and C4 plants and the
conditions they can withstand is paramount to introducing new species in any
locality, as this underpins their successful growth and development in the
specified environment. Most C4 species are vulnerable to growth inhibition at
temperatures below 12 °C, although some have evolved and become adapted to
more temperate climates. C3 species can withstand temperatures as low as 0 –
5 °C but are far more vulnerable at high temperatures and when solar radiation
is high. Contrastingly, it is common for C4 species to thrive in temperatures
above 25 °C as their photosynthetic pathway is more efficient and more able to
cope with high temperature and solar radiation, resulting in greater growth and
productivity (Squire, 1990).
It is worth noting that calculations of dry matter production are not always
entirely accurate as components such as root biomass may not be taken into
account. Whilst this may not be significant when there are no other limiting
factors, root biomass may contribute up to 50% of total biomass under drought
conditions (Ong et al., 1996); prolonged and widespread periods of drought are
common in the Himalayan region, especially in the Lesser Himalaya (Rawat,
1995).
Water use
70% of annual water consumption in the Himalaya occurs during the four
months (July to October) of rainy season (Narain et al., 1998). Water use
efficiency may be estimated as the ratio of dry matter produced to the quantity
of water transpired over the same time period (Azam-Ali and Squire, 2002). As
dry matter production is linearly related to the quantity of solar radiation
absorbed, light is a crucial component in determining plant growth and
development. Solar radiation controls and dictates plant water status by
[46]
regulating stomatal aperture to optimise the balance between CO2 uptake and
water loss.
The balance between CO2 and nutrient uptake and water uptake and loss varies
within and between individual plant species, as do their respective root profiles,
influencing their ability to access water from different depths within the soil
profile. One simple advantage of mixed cropping agroecosystems is their ability
to exploit available water at different depths within the soil profile,
simultaneously. Soil water content and the spatial distribution of water, nutrients
and oxygen all affect rooting and crop density, as does the presence of stony or
compacted layers (Ong et al., 1996). Studies of an agroforestry system in the
Western Himalaya showed that seasonal crops exploited the upper 1.5 m of the
soil profile more exhaustively than trees, whereas the trees extracted water
down to a soil depth of 3.0 m (Narain et al., 1998). This pattern is fairly typical
when woody perennials are combined with pasture or crop species (Azim-Ali and
Squire, 2002).
Sole crops may have high water-use efficiency, one of the many factors which
are likely to have led to the traditional growth of sole crops throughout the
Himalaya. Even on large erosion plots with a slope of 4%, sole plantations of
Leucaena leucocephala and Eucalyptus spp. showed negligible runoff losses. In
these systems, water use approximated to annual rainfall, although mixed crops
still demonstrated more efficient soil water use as they exploited a greater
proportion of the soil profile and so provided greater biomass production (Narain
et al., 1998).
There are numerous examples of sole crops grown throughout the Himalayan
region which do not show efficient water use, especially in comparison with other
suitable species. Furthermore, traditional farming systems have led to
widespread soil degradation, loss of soil fertility and problematic levels of run-off
(Semwal et al., 2004).
It should be remembered that “annual water use is closely linked with runoff
reduction and the efficiency of land use” (Narain et al., 1998), demonstrating
the suitability and potential of agroforestry in the region, as this holistic
approach combines each factor to provide an effective land management plan.
Nutrient availability and uptake
Nutrient availability is often a limitation in the Himalaya, with a number of
primary factors contributing to this. Soil run-off and leaching, immobilisation of
[47]
nutrients in soil and the formation of new soils from inadequate parent soils, all
create shortages of macro- and micro- nutrients.
Zinc (Zn) deficiency is the most common micronutrient disorder in rice and
affects up to 50% of lowland rice soils (White & Zasoski, 1999; Dobermann &
Fairhurst, 2000). Seedling mortality, stunting, leaf bronzing, and delayed
flowering are all physiological disorders associated with Zn deficiency (Widodo et
al., 2010). The implications of crop failure are potentially huge in a region which
depends so heavily on subsistence living. Immobilisation of soil Zn is the most
common reason behind this in the Himalaya and can result from high soil pH and
excess bicarbonate, factors that typically occur in calcareous soils of the Indo-
Gangetic plains of India and Pakistan (Qadar, 2002).
Soil degradation, landslides and inappropriate land use all contribute to
increased run-off from agricultural lands. Nutrients are often suspended in the
water flow; heavy monsoon rainfall causes increased rain-splash, only
compounding the problem. Section 5.5 examines this process in detail. A study
in the Kumaun Himalaya found the main nutrient losses to be in the order: Ca >
K > P > N (Pandey et al., 1983). Other studies have found varying magnitudes
of nutrient loss in Himalayan ecosystems, very much dependent on the climate
and varying biological conditions. Studies of decomposing forest litter in the
Himalaya have found that most litters exhibit two phases in their nutrient
dynamics; a net immobilisation stage followed by a net release stage. Many
studies have evidenced the net immobilisation of nitrogen (N) and phosphorus
(P) (Upadhyay and Singh, 1989), a notable limitation to many species.
Agroforestry techniques are often attributed with increasing soil fertility and
their widespread use may benefit the nutrient losses currently suffered in the
Himalaya; Rai and Sharma (1998b) suggested that in the Sikkim Himalaya,
“agroforestry systems should be promoted in most of the areas where open
agricultural practices are followed” as “this land use promotes conservation of
soil, water, and nutrients.”
5.3 Competition and productivity
Competition for resources such as space, light, nutrients and water to increase
the likelihood of reproductive success, is an ever-present natural phenomenon in
the floral and faunal domains and underpins the processes of natural selection
and evolution. Light availability is rarely the primary limiting factor for crop
[48]
productivity in the Himalaya, although shading causes competition in mixed
stands as the interception of light is influenced by the collective spatial
distribution and orientation of each component species within their canopy.
Water use and transpiration rates are also affected by shading. Restricted
nutrient and water supplies are usually the key limiting factors. As described in
Section 5.2, nutrient leaching is common in the Himalaya, greatly reducing
nutrient supplies in agricultural lands.
Planning which species combination should be used in agroforestry (AF) systems
requires careful consideration of each of these points, with the aim of
sustainably maximising available resources for each plant and animal species
present to maximise system productivity. The definition of productivity is
ambiguous (Tagen, 2002) and depends on the desired balance between the
production of food and resources for sustenance, and those for sale or trade. As
Zhu et al. (2006) concisely noted, “the methods to describe and measure
productivity have failed to keep pace with production processes, resulting in a
totally vague, incomplete evaluation of production. Sometimes the serious
problem of pollution is ignored in the race to short-dated money making, thus
leading to a blooming and flooding pollution; sometimes the great ecological
benefits are ignored and the corresponding production processes suffer
drastically from ‘economic deficit’”. In its most basic form, productivity is
generally defined as the relation between input and output (Tangen, 2002). A
marked benefit of AF compared to conventional farming methods is its potential
flexibility to meet the environmental demands of competition and sustainability
whilst managing both agricultural and economic inputs and outputs.
Agroforestry systems may aim to improve the overall crop yields by utilising
available rainfall more effectively and increasing soil fertility and nutrient uptake,
although rural communities have not always received AF ventures
enthusiastically as competition between trees and crops can be seen to
overshadow the perceived benefits (Dhyani and Tripathi, 1998); until recent
years evidence in the agroforestry literature to support these perceived benefits
has been lacking (Jose, 2009).
Poor agroforestry management has also led to examples of trees being grown
alongside crop and shrub species with similar root profiles, leading to
unnecessary competition (Chirwa et al., 2007). There is, however, little or no
evidence to support the concept of niche separation, whereby it has been
suggested that annual crop species exploit only the upper soil profile while
[49]
perennial species primarily exploit the deeper horizons (Broadhead et al., 2003).
The height and consequent canopy shading caused by trees in agroforestry
systems must also be carefully managed to ensure that excessive shading does
not adversely affect the other species present; thus, understorey crops receive
reduced solar radiation due to shading by taller trees, thereby stifling overall dry
matter production and crop yield (Broadhead et al., 2003).
Simultaneous agroforestry systems (e.g. alley cropping, contour hedges,
parklands, boundary plantings, home gardens) provide more insight into
competition processes than sequential systems, which aim to maximise
productivity and environmental stability through rotational processes over a
predetermined period. It should be remembered that both systems aim to
achieve sustainable production through both long and short term strategies
(Thakur et al., 2007).
Alley-cropping is a simultaneous system in which competitive interactions take
place, usually between trees or shrubs and crops. The trees are grown in
hedges, between which food or resource crops are grown in ‘alleys’ of varying
width (Sanchez, 1995). Figure 5.9 shows an example of an alley-cropping
system. In the Central Himalaya, agroecosystems involving mixtures of trees
and crops are the predominant traditional form of land use (Semwal et al.,
2002), demonstrating that agroforestry techniques are not always an entirely
new concept to the local population. Crucially, sustainability of nutrient and
water supplies may be increased by assessing the species used.
Figure 5.9: Example of alley intercropping with millet, sweet potato, yams and maize interspersed with Gliricidia sepium hedgerow. (Adapted from Baidya et al.,
1992)
[50]
An increase in soil fertility is one property often attributed to agroforestry,
particularly when nitrogen-fixing grasses and leguminous species are used.
Thus, the presence of leguminous trees has been shown to increase soil fertility
significantly within a 2-3 year period (Ong et al., 1996). Pruning or ‘lopping’ tree
species to provide green leaf manure (GLM) is also used to increase soil fertility
for both crops and trees and could be referred to as biomass transfer as it may
substantially increase nitrogen status within the soil (Chirwa et al., 2003).
Although knowledge surrounding the effect of lopping trees on the productivity
of intercropped, understorey plant species is limited, evidence has shown that as
little as 12% of the photosynthetically active radiation (PAR) reaching the
canopy surface of agroforestry systems reaches understorey crops in the
absence of tree pruning and mean daily temperature may be decreased by 2 °C.
The decrease in temperature, itself, may benefit or limit the growth of a species,
depending on its ecological niche. Furthermore, the grain yields of various inter-
cropped species alongside un-pruned trees have been found to be 16 – 21% of
those obtained in the corresponding full lopping treatments during the dry
season, and only 3 – 5% during the rainy season. Yields from winter crops in the
un-pruned treatment were also low at 29 – 32% of the fully pruned treatment
during the dry season and 6 – 8% during the rainy season. Consequently, many
Himalayan land-owners already practice full lopping during the winter season in
traditional intercrops (Semwal et al., 2002).
Semwal et al. (2003) investigated the nutrient release patterns of leaf litter from
six multipurpose tree species found in the Central Himalaya in respect to climatic
conditions and concluded that “a linear combination of rainfall and temperature
explains the variation in monthly [nutrient] mass loss better than rainfall and
temperature independently.” Regulating these abiotic factors through concise
management of plant biological interactions is therefore key to increasing grain
yield, productivity and sustainability in agroforestry systems.
A balance must be achieved between managing competition for limiting factors
such as nutrients and water and maintaining maximum productivity of the land.
[51]
5.4 Erosion and soil degradation
‘Soil degradation, the cancer of the land, is universally held responsible for the
downfall of many previously flourishing empires.’
Figure 5.10: Grewal et al. (1990) describe the enormous impact of soil
degradation throughout history.
Impact of erosion
Erosion is widespread throughout the Himalayan region, caused and
compounded by a number of factors ranging from climate change and glacial
melting to deforestation, livestock grazing and improper land management, all of
which directly accelerate land degradation. The effects on nutrient availability,
land stability and water flow are equally widespread and can be explored on
many levels. This section aims to identify the scale of soil degradation in the
region and the feasibility of counteracting its effects using sustainable
agroforestry techniques.
Areas of the Himalaya which are particularly susceptible to high rainfall are the
Darjeeling, Bhutanese and Cherrapunji regions, where annual total rainfall is
2000-4000, 4000-6000 and 6000-23000 mm, respectively (Soja and Starkel,
2007). Each provides an interesting case study, giving an indication of how
areas with differing geographical properties respond to extremely high rainfall
with regard to their soil properties and erosion. The Cherrapunji region
experiences dozens of extreme rainfall events each year. Dense vegetation cover
used to provide a physical barrier, protecting the soil. However, following
deforestation and intensive land use, extensive loss of fertile soil has occurred
either exposing the bedrock or a new debris top layer which provides only partial
protection of the surface against continued degradation; these changes facilitate
rapid overland flow. In the Bhutanese and Darjeeling regions, rainfall thresholds
may be exceeded 2 – 3 times in a single century when the system is still up to
an equilibrium state due to lack of anthropogenic intervention (Soja and Starkel,
2007). Thus, whilst water flow from the high Himalaya may be uncertain, or
indeed set to increase due to the continued melting of glaciers, responsible land
use may still allow a reasonable threshold of stability to be achieved across the
rest of the Himalaya.
Certain areas suffer land degradation on a massive scale. For example, Jammu
and Kashmir in the Western Himalaya suffer from severe land degradation
across 73% of the state (Singh, 1998), whilst about one third of the area of
[52]
Nepal has little or no vegetation (Paudel et al., 2009). However, widespread
policy changes to help maintain land stability have many socio-economic risks
associated with agricultural and timber prices, wages, risks to agricultural
productivity, population density in rural areas and access to remaining forests
(Upadhyay et al., 2006). Under-resourced and poor Himalayan governments are
often forced to decide between short- to medium-term economic growth through
increased capital ventures which may destroy agricultural land, and slow but
steady sustainable agricultural development which could ensure the social and
biological problems caused by erosion are eventually overcome.
Combating soil degradation
As previously noted, poor soil fertility is one of the main limiting factors to
agricultural productivity in the Himalaya. Consequently, an increase in soil
fertility is promoted as a primary benefit of agroforestry (Dadhwal et al., 1988).
Lopping of tree species and ongoing application of green leaf manure (GLM)
evidently aids the maintenance of healthy soil, as do well managed fallows and
constant monitoring of biomass transfer within a system. Even within
sustainable agricultural systems, however, soil nutrients have been shown to be
the least resilient component (Young, 1989), meaning they are of particular
importance to the subsistence or commercial success of land-owners.
Steep hillsides are most vulnerable to erosion and the associated loss of fertility
and so have lent themselves to much experimentation by local populations and
academics. Any approach implemented within AF systems must consider the
maintenance of available soil phosphorus as being of paramount importance, as
biomass transfer techniques and improved fallows rarely provide adequate
replacement of the nutrient after its incorporation into grain (Young, 1989).
Suppressing and controlling erosion also affects Himalayan watercourses at both
local and regional levels. Changes in eutrophication, siltation and the speed of
ambient flow (Sanchez, 1995) are all considerations when implementing new
techniques, although reduced erosion generally has a positive impact.
The most popular agroforestry technique for controlling erosion, especially on
steep hillsides, is the planting of contour or barrier hedgerows. Species from
families such as Leucaena and Eucalyptus are ideally suited to Himalayan
climates and may bring numerous benefits to the soil. The concept of soil health
can be used to provide a holistic description of both soil fertility and stability; as
fertile soil promotes successful plant growth, which in turn enhances soil stability
through root growth and protection from wind and rain, maintaining healthy soil
[53]
is essential to reducing erosion. Sole crops may also be planted on some plots
forming part AF systems. The extensive rooting of species such as maize,
coupled with their dense canopy cover and consequent shelter from rain-splash
and wind, leads to an increase in stability compared to other farming practices.
Narain et al (1997) found that runoff and soil loss were reduced by 27 and 45%
respectively by contour cultivation of maize, whilst contour-planted tree rows or
Leucaena hedges reduced the runoff and soil loss by 40 and 48% respectively
during the wet and dry seasons. Clearly, contour-planted barriers in the form of
trees or hedgerows are the most effective method of combating soil degradation
on hillsides.
The topography of large parts of the Himalaya dictates that the planting of trees
is unattainable; rice paddy fields provide an excellent example of this due to the
small riser area between paddies. In such instances, nitrogen-fixing grasses are
far more suitable for providing stability through the binding effects of their root
systems and symbiotic interactions with the soil. Figure 5.11 shows an example
of this practice in the mid-hills of Nepal.
Nitrogen-fixing grasses are traditionally grown throughout the Himalaya, many
of which are endemic to the region and thought to have medicinal properties.
Parandial et al. (2005) found more than 300 rare and endangered species of
medicinal plants with therapeutic properties and concluded that the “over
exploitation of these precious materials from Himalayan forest ecosystems over
the last few decades has not only pushed these species towards extinction but
also enhanced the problem of soil erosion, land degradation and loss of
biodiversity in the area. Introduction of nitrogen fixing plants may provide an
important tool for the ecorestoration attempts in this area. Advocating nitrogen
fixing plants having medicinal uses may provide wider acceptability among the
local populace from an economic as well as soil conservation point of view. The
adoptability of indigenous species may be useful for planting and rejuvenating
the degraded sites in different altitudinal zones of the Himalayan ecosystem.”
[54]
Figure 5.11: Communal paddy fields in the Nepal mid-hills. The risers for the upper paddies have been planted with nitrogen-fixing grasses to help provide stability and combat degradation. The lower area shows the exposed risers of un-treated paddies, which are vulnerable to erosion caused by rain-splash and
wind.
In the Sikkim Himalaya, Sharma et al. (2001) found that more than 72% of
nutrient losses were attributable to agricultural land use and concluded that
forests and agroforestry techniques, including the introduction of cardamom
trees, provided more effective soil conservation than other forms of land use.
Other interventions such as the cultivation of broom grass on terrace risers,
nitrogen-fixing Albizia trees for maintenance of soil fertility and plantation of
horticulture trees reduced soil loss by 22%.
5.5 Sustaining and improving Himalayan water flow
Soil and water conservation in the Himalaya are closely interlinked. The
techniques described in the previous section for reducing soil degradation and
increasing stability often lead to a reduction in surface run-off as well as
protecting the surface from wind and rain-splash (Young, 1989). Dhruva
Narayana (1987), Director of the Central Soil and Water Conservation Research
and Training Institute, provided a valuable overview of the downstream impacts
of soil conservation in the Himalayan region. He indicated that, of India's 328
[55]
mha of land area, approximately 175 mha are suffering from intense soil erosion
(Ives and Messerli, 1989). In the past 20 years, soil erosion and run-off have
become even more of a pressing issue, leading to the International Centre for
Integrated Mountain Development (ICIMOD) initiating the Too Much Too Little
Water project to assess local adaption strategies for minimising water stress and
associated hazards in the Himalayan region. As explained in Section 5.1, water
distribution across the region is by no means uniform, with some areas regularly
facing drought whilst others experience floods.
The implications of problems with Himalayan water supplies range from localised
crop failure caused by one-off events to the environmentally-induced onset of
progressively lower yields, unpredictable downstream water availability,
widespread soil erosion and regional water shortages.
The world’s water resources have come under increasing pressure in recent
years due to rising global populations and realisation of the impacts of climate
change. The socio-economic implications of changes in Himalayan water flow
and their likely link with anthropogenically-induced climate change were
considered in Chapter 2.
The Intergovernmental Panel on Climate Change (IPCC) 2007 Assessment of
Climate Impacts provides the most up-to-date and thorough analysis of possible
methods for sustaining and improving Himalayan water flow. The document
focused on the concepts of adaption and mitigation. The IPCC definition of the
latter is “an anthropogenic intervention to reduce the sources or enhance the
sinks of greenhouse gases”, whereas adaption could be referred to as the ability
of a system to adjust to changes whilst moderating potential damage and taking
advantage of opportunities. It could also refer to coping with the consequences.
Evidently, a combination of mitigation and adaption processes must be put into
place on a global scale for the human population to overcome the numerous
adverse effects of climate change. Figure 5.12 is taken from the IPCC AR4
synthesis report and shows the suggested adaption options available in the
sectors of water and agriculture. Demonstrating compatability between these
suggestions and the use of agroforestry systems across the Himalaya is crucial
in providing confidence that such systems offer viable methods for improving
water flow in the context of a changing global and regional climate.
[56]
Figure 5.12: The adaption options, underlying policy frameworks and key constraints and opportunities to implementation with regard to water and
agriculture suggested by IPCC (2007).
Reducing run-off
Conserving water involves controlling its overland flow which may be achieved
by reducing run-off and the potentially detrimental associated effects of
leaching, eutrophication and erosion. Limited studies have been undertaken
which directly link run-off with land use for various Himalayan watersheds.
Sharma et al. (2007) examined five watersheds representing the mid-hills of the
Himalaya in both China and India to gain an understanding of hydro-ecological
linkages of changes in land use. The natural forest decreased in both countries
between 1988 and 1997, with the greatest change of 20% being found in
Mamlay Watershed, India. The area under open forests increased in most cases
during this period. In the Indian watersheds, the area of agricultural land
increased, with the highest value of 16% being recorded in the Mamlay
watershed. The reverse trend was recorded in the Chinese watershed where the
area occupied by cropland and tea gardens declined substantially, whereas the
area of forest increased by 38% between 1982 and 1998. It was concluded that
the “promotion of forests and agroforestry in combination with rehabilitation of
degraded land in the mountain watersheds could improve land husbandry for
providing hydrological benefits to both upstream and downstream users.” Thus,
it could be determined that not all agroforestry systems necessarily provide
innate hydrological benefits, but if managed properly and with due consideration
for factors such as run-off and the overall flow of water, upstream and
downstream populations will both benefit. Other studies have reached similar
conclusions (Rai and Sharma, 1998a; 1998b).
[57]
Fertile soils which are adequately protected against rain-splash and wind erosion
by contour hedges and other agroforestry techniques help to reduce run-off.
Nutrient leaching associated with the process of run-off also causes problems
with crop production. The strategy of maintaining soil fertility through
appropriate biotic and abiotic interactions is once again paramount to the
success of agroforestry.
Water harvesting
Water supplies in the Himalaya are most commonly sourced from upstream
locations, be it through direct piping for human use or irrigation, or through the
natural flow of water from the mountains to the foothills. In the Indian
Himalaya, there is evidence of pre-colonial community ownership rights over the
use of local natural resources such as water, whereby local communities
managed their own water supplies, giving rise to a unique water harvesting
culture. Water was revered and regarded as sacred, as evidenced by the
exquisite ornamentations and architecture of the structures surrounding bodies
of water. These structures have shown incredible longevity, providing historical
confidence for the sustainability of such systems. The colonial intrusion disturbed
the community mode of management, leading to private and state property
rights over common property rights, and this situation has not changed since
Independence (Rawat and Sah, 2009).
Himalayan environments are ecologically fragile due to altitudinal, climatic and
topographical variations. The consequent variety of crops grown and number of
traditional farming methods used is huge. Localised water harvesting may not,
therefore, be appropriate for all parts of the Himalaya, or even applicable for the
same uses; different communities have different water use patterns and needs,
depending on population, whether irrigation is used, and so on. Specific
combinations of water harvesting and irrigation have been shown to reduce
environmental impacts and benefit downstream water flow (Kumar et al., 2009).
The economic cost of water harvesting must be explored through detailed design
of water-harvesting structures using locally available materials and adaptable to
the socio-economic conditions of the beneficiaries, although there is little
research in this area applicable to the Himalaya. This may be due to the overall
availability of water through high rainfall in the monsoon season. Such studies
have been undertaken in semi-arid Indian regions such as Rajasthan, which
found that cost-effective water-harvesting systems are gaining wide acceptance
[58]
and popularity in the region through the activities of some non-governmental
organisations (Machiwal et al., 2004).
A combination of utilising available water and controlling its flow throughout the
Himalaya will help to sustain communities with sufficient water supplies without
affecting downstream users. Specific agricultural practices employed through
agroforestry systems can help to reduce run-off and so decrease the numerous
detrimental effects currently being felt throughout the Lesser Himalaya.
5.6 Introducing livestock
Livestock is bred sporadically in the Himalaya. Whilst commercial ventures exist
to supply urban areas with meat and dairy products, the vast rural population
relies predominantly on local markets and passing trade. Hindus often follow
ahimsā in rural areas and this, coupled with Buddhist beliefs, means that
vegetarianism is relatively widespread, reducing the demand for meat. Meat is
also an expensive commodity in such a poor region and protein intake is mostly
from non-meat products such as lentils. There are many potential advantages to
keeping livestock for poor land-owners, provided they are introduced into a
system in which their lives and well-being are sustainable and affordable.
Nutrition is provided for subsistence communities through dairy products such as
eggs and milk from buffaloes, goats and chicken and fish ponds may be included
in modified land use systems to provide a further food source to farmers.
Surplus supplies can be sold or traded with other community members. Animal
waste can also be applied as manure, giving constant supplies of fertiliser. An
initial investment of economic capital is evidently required to purchase animals
and this first hurdle is already being widely subsidised by non-governmental
organisations (NGOs) throughout the Himalaya. The types of animals which can
feasibly be introduced to various communities is shown in respect to altitude in
Figure 5.13, along with the opportunities within specific agroforestry systems,
depending on available resources.
[59]
Figure 5.13: Feasible crops and livestock across the Himalayan region, according to altitude (Adapted from Baidya et al., 1992).
An obvious limitation to raising livestock is their nutritional requirements.
Maintaining efficient land management should ensure that enough food is
produced to facilitate a net benefit from the animal’s presence. For many
species, including buffalo and goat, nitrogen-fixing grasses used to alleviate land
degradation can be harvested as a food-stuff for a substantial period of the year.
Many agroforestry systems already incorporate livestock as indicated by Figure
5.14, which shows livestock in Kaule, Nepal.
Figure 5.14: (a) A buffalo, used for milk production, being bathed by Tamang boy on his family’s land (Schick, 2009). (b) Chickens being transported from
local farmer’s land to a community market for sale.
[60]
Chapter 6: Conclusions
Successful, sustainable agriculture showing high productivity in the Himalaya
faces a number of constraints brought about by the biotic and abiotic
environments. Social constraints are also shown to dictate land use. Current
land use practices, particularly reliance on traditional subsistence agriculture as
well as the unflinching use of sole crops in many Himalayan localities, have
contributed to widespread land degradation and depletion of land resources.
Fluctuations in upland water supplies and increasing inconsistency in monsoon
duration and rainfall, have been widely attributed to climate change and
demonstrate another facet affecting the currently low levels of crop productivity.
The most limiting abiotic factors in the region are usually inadequate water
supplies and poor soil fertility. Declining productivity and increased relative
poverty have led to the social phenomenon of rural-urban migration; the
potential economic benefits of an urban lifestyle often more alluring than the
hardships of traditional subsistence. The massive increase in urban populations
and population growth in general, also means there is more demand than ever
before for food, water and resources which has led to unsustainable farming
practices such as deforestation for timber and fuel. Deforestation and removal of
vegetation has been shown to adversely affect the fragile Himalayan ecosystem,
further increasing soil degradation, run-off and other detrimental effects. Moving
forwards, it is therefore essential for the concept of sustainability to be at the
forefront of agricultural development in the region.
Sustainable agriculture is well-suited to the Himalaya as it is imperative that
poor land-owners farm within their means and develop farming techniques to be
sustained for years or generations to come. If a system is sustainable, this
inherently means the environment must remain largely undamaged whilst
maintaining social and economic acceptability. Low-external-input agriculture
reduces the financial burden placed on rural communities and will also ensure
the adverse effects of mechanised agriculture in more developed countries (i.e.
further soil degradation, nutrient loss, acidification and salinisation) do not come
to fruition.
Agroforestry as a sustainable system has been employed in various global
locations for some decades, although detailed scientific analysis of each specific,
interrelated aspect or technique has only recently occurred.
Over-estimations of productivity increases and the general successes of the
system may be to blame for its somewhat gradual and sporadic acceptance
[61]
throughout developing nations. With an increased level of research into the
many aspects of tree-crop interactions, specific agroforestry systems may now
be expertly designed for any given Himalayan location. The specificity required
in system design to achieve an overall increase in the desired outcomes of
increasing living standards, biodiversity and sustainability, may be seen as a
drawback. However, there are few viable alternatives to traditional land use
systems and whilst specificity may, in one sense, be a drawback, it also results
in huge flexibility between physical environments and social needs. As numerous
studies have shown, agroforestry is also an affordable alternative practice.
A holistic approach to agroforestry can prioritise and address specific lifestyle
factors. For example, livestock may be introduced for nutritional benefit or
financial security. A net gain in productivity is achievable through better use of
available resources and careful management of each biological component. The
ability to determine both temporal and spatial factors to increase net gain is also
an advantage. Studies into simultaneous techniques such as alley-cropping
provide insight into the need for effective management of each component,
however, as the implications of competition must never outweigh the overall
benefits.
Further understanding of the physiological interactions between various species
is needed to conclusively determine the overall effectiveness of such systems.
Factors like root and shoot pruning, management of vegetation canopies,
understanding allelopathic interactions and managing species’ root profiles, all
require research to ensure the correct balance between tree and crop growth is
achieved, to suit the farmer’s needs.
There is a wealth of information supporting the positive correlation between
agroforestry implementation and increased environmental stability and
sustainability. Decreased soil degradation means that the system maintains
more predictable water flow throughout and increases soil fertility due to
reduced run off. Up and downstream water users also benefit. Regional erosion
and the associated problems of crop failure, diverted water flow and severed
transport links could be greatly reduced with the introduction of a more
biodiverse and edaphically stable agricultural system.
The need for external intervention (governmental, non-governmental; national,
international) to educate and empower indigenous and isolated populations is
innate when attempting to solve the concurrent environmental and social
problems of the region; unavoidable if necessary changes are to be made.
[62]
Economic development and agricultural sustainability are irrefutably linked for
this reason. Various organisations representing each respective sector must
work together to achieve a balance between economic prosperity and long-term
environmental sustainability in the region.
[63]
Chapter 7: Glossary of key organisations
Himalayan Research and Cultural Foundation
A “multi-disciplinary research, cultural and development facilitative organisation
set up by eminent area specialists, environmentalists, development experts,
literateurs and cultural personalities” running in conjunction with UNESCO.
(www.himalayanresearch.org, cf. W10)
International Centre for Integrated Mountain Development (ICIMOD)
“A regional knowledge development and learning centre serving the eight
regional member countries of the Hindu Kush-Himalayas”, focussing particularly
on the effects of globalisation and climate change. (www.icimod.org, cf. W11)
International Fund for Agricultural Development (IFAD)
“A specialised agency of the United Nations, established as an international
financial institution in 1977 as one of the major outcomes of the 1974 World
Food Conference.” The institution works in developing countries around the
globe, with the aim of eradicating rural poverty. (www.ifad.org, cf. W12)
Nepal Agroforestry Foundation (NAF)
Working across Nepal, NAF takes “a holistic approach to the long-term goal of
sustainable community forest management”, most notably through home
nursery training and women’s cooperatives. (www.forestrynepal.org, cf. W13)
United Nations Development Program (UNDP)
A United Nations program which aims to promote democratic governance as well
as researching poverty reduction and increasing affordable energy services for
the poor. (www.undp.org, cf. W14)
United Nations Educational, Scientific and Cultural Organisation (UNESCO)
UNESCO runs several developmental and environmental programmes across the
region, including the International Hydrological Program (IHP), an “international
scientific cooperative programme in water research, water resources
management, education and capacity-building” and Flow Regimes from
International Experimental and Network Data (FRIEND) which aims to provide a
“better understanding of hydrological variability and similarity across time and
space [in the Himalaya]”. The Great Himalayan National Park is a UNESCO World
Heritage Site due to its “exquisite floral and faunal biodiversity”.
(www.unesco.org, cf. W15)
[64]
The World Conservation Union (IUCN)
The IUCN works towards developmental and environmental improvements
throughout the world by supporting scientific research as well as managing field
projects which “consolidate governments, non-government organizations, United
Nations agencies, companies and local communities to develop and implement
policy, laws and best practice.” (www.icun.org, cf. W16)
World Meteorological Organisation (WMO)
The WMO is a worldwide organisation which aims to ensure that “basic weather,
climate and water services are made available to anyone who needs them, when
they need them.” In the Himalayan region, the WMO has been responsible for
launching the Operational Hydrological program (OHP) and Hindu Kush
Himalayas (HKH)-FRIEND project. (www.wmo.int, cf. W17)
[65]
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Note: Figures 1.3, 5.6, 5.11 and 5.14b by author.