Agricultural Water Management xxx (2009) xxx–xxx

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Managing water by managing land: Addressing land degradation to improvewater productivity and rural livelihoods§

Deborah Bossio a,*, Kim Geheb b, William Critchley c

a International Water Management Institute (IWMI), P.O. Box 2075, 127 Sunil Mawatha, Battaramulla, Sri Lankab International Water Management Institute, P.O. Box 5689, Addis Ababa, Ethiopiac Natural Resource Management Unit, CIS/Centre for International Cooperation, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands

A R T I C L E I N F O

Article history:

Available online xxx

Keywords:

Land use management

Land degradation

Water management

Water productivity

A B S T R A C T

The premise of this paper is that the key to effective water resources management is understanding

that the water cycle and land management are inextricably linked: that every land use decision is a

water use decision. Gains in agricultural water productivity, therefore, will only be obtained

alongside improvements in land use management. Expected increases in food demands by 2050

insist that agricultural production – and agricultural water use – must increase. At the same time,

competition for water between agricultural and urban sectors will also increase; and the problem is

further compounded by land degradation. A global survey suggests that 40% of agricultural land is

already degraded to the point that yields are greatly reduced, and a further 9% is degraded to the

point that it cannot be reclaimed for productive use by farm level measures. Soil erosion, nutrient

depletion and other forms of land degradation reduce water productivity and affect water

availability, quality, and storage. Reversing these trends entails tackling the underlying social,

economic, political and institutional drivers of unsustainable land use. This paper is based on a

review of global experiences, and its recommendations for improving water management by

addressing land degradation include focusing on small scale agriculture; investing in rehabilitating

degraded land to increase water productivity; and enhancing the multifunctionality of agricultural

landscapes. These options can improve water management and water productivity, while also

improving the livelihoods of the rural poor.

� 2009 Elsevier B.V. All rights reserved.

Contents lists available at ScienceDirect

Agricultural Water Management

journal homepage: www.e lsev ier .com/ locate /agwat

1. Introduction

Land degradation reduces water productivity at field andlandscape scales, and affects water availability, quality, andstorage. Because of this strong link between land and waterproductivity, improving water management in agriculture requiresthat land degradation be mitigated or prevented. Optimisticscenarios suggest that, by 2050, 30–40% more fresh water will beused by agriculture than is used today (De Fraiture et al., 2007). If,however, agricultural water productivity does not improve, theagricultural sector will consume an additional 70–90%. In thisreview of global experiences relating to land degradation, wehighlight important degradation processes that are closely linkedto water use and management, underlying drivers of that

§ This paper is based on a chapter by Bossio et al. (2007).* Corresponding author.

E-mail address: d.bossio@cgiar.org (D. Bossio).

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), doi

0378-3774/$ – see front matter � 2009 Elsevier B.V. All rights reserved.

doi:10.1016/j.agwat.2008.12.001

degradation, and review options that can help mitigate landdegradation to improve water productivity.

2. The land–water connection

Despite being conducted during the 1980s, the Global Assess-ment of Human-induced Soil Degradation (GLASOD) (Oldeman,1991) remains the only uniform global source of degradation data.According to GLASOD estimates, degradation of cropland appearsto be most prevalent in Africa, affecting 65% of cropland areas,compared with 51% in Latin America and 38% in Asia. Degradationof pasture is also most serious in Africa, affecting 31% ofpastureland, compared with 20% in Asia and 14% in Latin America.Forestland degradation is most pronounced in Asia, affecting 27%of forestlands, compared with 19% in Africa and 14% in LatinAmerica. Based on GLASOD, Wood et al. (2000) estimated that 40%of the world’s agricultural land is moderately degraded, and afurther 9% strongly degraded, reducing global crop yield by 13%.Estimates of land use degradation rates are even more uncertainthan degradation extent estimates, and vary from 5 to 10 million

y managing land: Addressing land degradation to improve water:10.1016/j.agwat.2008.12.001

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hectares a year being lost to production (Scherr and Yadav, 1996).The degradation processes that contribute to these global trendshave important negative impacts on water cycling and waterproductivity.

2.1. Loss of organic matter and the physical degradation of soil

Soil organic matter is integral to managing water cycles inecosystems. Decreases in soil organic matter favours thecollapse of soil aggregates and thus crusting and sealing ofthe soil surface, giving rise to reduced porosity, less infiltration,and more runoff (Valentin and Bresson, 1997). Soil surfacecompaction, by heavy machinery or large numbers of livestock,for example, can cause overland flow, even on usually permeablesoils (Hiernaux et al., 1999). Such changes can increase therisk of flooding and water erosion. On sloping terrain, morefrequent and more intense runoff increases interrill erosion,reduces subsurface flow, and gives rise to rills and subsequentlygullies. In drier environments, these processes also increasewater loss through evaporation. As these environments aredegraded, a positive, self-accelerating feedback loop is created(Fig. 1).

2.2. Nutrient depletion and the chemical degradation of soil

Globally, only half of the nutrients that crops take from the soilare replaced. When this depletion results in essential nutrientsbecoming more limiting than water, water productivity declines(see Bossio et al., 2008, for a technical discussion). In many Asian,African, and Latin American countries, the nutrient depletion ofagricultural soils is so high that current agricultural land use is notsustainable (Craswell et al., 2004). Macronutrient depletion inmany Asian countries in the order of 50 kg/(ha year) (Sheldricket al., 2002). Trends are even worse in Africa (Fig. 2; Smaling, 1993;Stoorvogel et al., 1993), where nutrient depletion is nowconsidered the chief biophysical factor limiting small-scale farmproduction (Drechsel et al., 2004). Other important forms ofchemical degradation are the depletion of trace metals such aszinc, which causes productivity declines and can affect humannutrition (Cakmak et al., 1999; Ezzati et al., 2002).

A final key chemical degradation problem is that of secondarysalinization, which is a serious threat to sustainable irrigatedagricultural production. Although data are poor, estimates indicatethat, globally, 20% of irrigated land suffers from secondary

Fig. 1. A negative cycle of soil–water relationships leads t

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), do

salinization and water logging (Wood et al., 2000) induced bythe build-up of salts introduced via irrigation water.

2.3. Soil erosion and sedimentation

Soil erosion rates almost always rise substantially withagricultural activity. Onsite, soil erosion reduces crop yields andwater productivity by removing nutrients and organic matter.Yield impacts can be severe and vary with soil type, and areparticularly evident in the early stages of erosion. In Ethiopia,soil erosion reduces yields by an average of 1–2% annually,resulting in base yields of 300–500 kg/ha (Hurni, 1993), whileelsewhere, Stocking (2003) has demonstrated dramatic declineson a wide range of soils. Erosion also interferes with soil–waterrelationships: the depth of soil is reduced, diminishing waterstorage capacity, and damaging soil structure thus reducing soilporosity. Surface sealing and crusting reduce infiltration andincrease surface runoff, which is a problem in itself and resultsin a net loss of water for crops. Downstream, the impact of soilerosion is sedimentation, a major form of human-induced waterpollution.

2.4. Degradation of landscape function

Processes such as those above, combined with the simplifica-tion of vegetative cover, alter water cycles and have importantconsequences for water quality and water availability. Soildegradation reduces the efficiency of natural filtration processesin landscapes, and thereby exacerbates water pollution when itincreases the proportion of water that flows rapidly over land.Surface runoff carries microbes, nutrients, organic matter,pesticides, and heavy metals from surface soils to water bodies.Phosphorus levels, for example, can be approximately 10 timeshigher in surface runoff than in groundwater (Gelbrecht et al.,2005). There is also increasing evidence that soil degradation andvegetative change that result in evaporation and convectionchanges can also have large impacts on local precipitation patternsand water availability (Ryszkowski and Kedziora, 2008). This is inaddition to the loss of filtration functions, and base flow bufferingthat are considered essential regulating and supporting ecosystemservices of landscapes (MEA, 2005). Land degradation at thelandscape level has a significant impact also on biodiversity – bothabove and below ground – and this impairs overall ecosystemfunction.

o increasing degradation. Source: Bossio et al. (2007).

y managing land: Addressing land degradation to improve wateri:10.1016/j.agwat.2008.12.001

Fig. 2. Nutrient balance estimates for selected countries in Latin America, Asia, and Africa show nutrient depletion in many countries. Source: Craswell et al. (2004) and

Sheldrick et al. (2002).

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3. The drivers of land degradation

If land degradation is understood as a process that negativelyaffects soil properties by diminishing their ability to supportagricultural crops,1 it is then a process that commences almost assoon as land is tilled. Hence, human activities – principallyagriculture – must be understood as the main driver of soildegradation, even though certain land use strategies can minimizeor even prevent such degradation, as we will discuss below. Likeany resource, the management of land use has more to do withmanaging people than it does the management of land per se(Blakie, 1985). The key variables here are the factors that influencepeoples’ access to land, and these are, in the main, a function ofhuman relationships. Below, we provide a non-exhaustive list ofthe key socio-political drivers of land degradation.

3.1. Population density

Poverty coupled with high population densities is frequentlycited as a key cause of land degradation (cf. WCED, 1987). Therecan be little doubt that the rural population will increase in thefuture. The evidence, however, suggests that population density inand of itself need not necessarily be a cause of land degradation (cf.Boserup, 1965; Tiffen et al., 1994; Templeton and Scherr, 1999).Hence, it must be the context within which dense populations ofland users exist that determines whether or not they mismanageland and water.

1 Much recent thought on environmental change argues for the process to be

understood as ‘transformation’ rather than a linear movement from a ‘good’ or

‘pristine’ state to a ‘bad’ or ‘degraded’ state (Gillson et al., 2003). This definition

understands the transformation of land as degradation from a state desired of it by

human activities.

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), doi

3.2. Misguided policies

Policies often artificially ratchet up the number of people perhectare of land, and/or concentrate poorer people on fragile,degradation-prone lands. In Lao PDR, policies outlawing shiftingcultivation in forests resulted in the resettlement of thousands ofpeople on to relatively small plots of land. Natural growth coupledwith resettlement and conservation policies led to a populationdensity exceeding 350 inhabitants/km2 of arable land in a countrywhere the average population density is less than 15 inhabitants/km2. Land degradation in these resettlement areas has been severe(Lestrelin et al., 2005). Policies in Latin America often favour largelandowners and provide favourable financial conditions for thedevelopment of large ranching areas. In Mexico, land distributionpolicies favour the non-poor, 80% of whom inhabit more desirableflat lands, while 66% of the rural poor live on lands with a greaterthan 5% slope (Bellon et al., 2005). Indeed, 66% of the poor in thedeveloping world live on marginal quality land (Scherr, 1999).

3.3. Security of access

Land tenure refers to the system of rights and institutions thatgovern access to and use of land and other resources (Maxwell andWeibe, 1999); it does not refer to private ownership alone. Farmersare more likely to invest in sustainable land management whenthey have secure access to the land they farm. Where access isinsecure or has broken down, open-access conditions often arise,almost always leading to overexploitation and degradation.

3.4. Gender relations

Relations between men and women are integral to land usedecisions and land husbandry. Women are the primary users of

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agricultural land in developing countries. They constitute up to90% of the rice-producing labour force in Southeast Asia andproduce up to 80% of basic household foodstuffs in sub-SaharanAfrica (Lado, 1992). Despite women’s major contribution toagriculture, men – particularly in Africa – retain most ownership,control, and decision-making power over agricultural resources,including land (Ellis, 2000). The result is that women are oftenexcluded from decisions that affect its use. The result can beunsustainable resource exploitation. When women are the farm-ers, for example, but cannot access agricultural inputs, soil nutrientdepletion can result. Evidence shows that when women haveaccess to inputs yields can be improved (Alderman et al., 2003),and when women control land use decision-making through localinstitutions, forest resources can be managed in a more sustainablemanner (Bushan, P., Nepal Water Conservation Foundation, Nepal,personal communication).

4. Solutions

4.1. Focusing on smallholder agriculture

By 2050, global food demand will be 70–90% higher thancurrent requirements. If water productivity in agriculture remainsat present levels, water demands will grow by a similar amount(De Fraiture et al., 2007). While land area available for furtherexploitation for agricultural production varies by region – Asia isalready very land constrained while Latin America still has thepotential for significant areas to be converted to agriculture –increases will be at the expense of forest, other natural ecosystems,or into climatically marginal grazing lands. At the same time, ifdegradation trends continue at present rates, along with anexpanding area under urban development, the amount of landavailable to farming will actually decline. As such, an intensifica-tion of agriculture is the most promising option for increasing foodsupplies to the globe’s growing population, particularly in rainfedareas (De Fraiture et al., 2007). The degree to which this is feasiblewill be limited by climate change outcomes. To make intensifica-tion sustainable in the long term, resource degradation needs to bemitigated or prevented, while the ecosystem services of the landneed to be increased (McNeely and Scherr, 2003). A focus onsmallholder agricultural systems to achieve the required intensi-fication not only of land, but also water use and improved watermanagement, makes sense because of the great extent of thesefarming systems and their resource efficiency. The smallholderunit is an important intervention point for influencing land andwater use management to have a discernable, positive impact onrural livelihoods because the largest proportion of the developingworld’s undernourished people are concentrated among small-holder agricultural groups (FAO, 2004).

Table 1Summary of global adoption and impact of resource-conserving agricultural technolog

FAO farm system categorya No. of farmers Hectares unde

Smallholder irrigated 172,389 357,296

Wetland rice 7,226,414 4,986,284

Smallholder rainfed humid 1,708,278 1,122,840

Smallholder rainfed highland 387,265 702,313

Smallholder rainfed dry/cold 579,413 719,820

Dualistic mixedc 466,292 23,515,847

Coastal artisanal 220,000 160,000

Urban-based and kitchen garden 206,492 35,952

Total weighed meand 10,966,543 31,600,351

Source: Noble et al. (2006).a Based on the farming systems classification of Dixon et al. (2001).b Increase from levels before initiation of the project.c Mixed large commercial and smallholder farming systems, mainly from southern Ld Based on the area occupied by each farming system.

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), do

Globally, 85% of farms are of less than 2 ha in size. Most of theseare in Asia–China, for example, 98% of farms are less than 2 ha(Nagayets, 2005). In Africa, most arable farming is also carried outon small plots, and average farm sizes here are approximately1.6 ha. In contrast, the average North American farm is 121 ha, andthe average European farm 27 ha (Von Braun, 2005). It is nosurprise, therefore, that smallholders carry out 60% of globalagriculture, providing 80% of food in developing countries(Cosgrove and Rijsberman, 2000).

Research suggests that small farms can be more resourceefficient than large farms. Small farms make the most efficient useof family labour. The value added per unit of capital invested onsmall farms (10–50 ha) exceeds that of large, non-plantation,farms (200–500 ha) (Van Zyl et al., 1995).

4.2. Investing in rehabilitation of degraded land to increase water

productivity

Over the last two decades, new thinking has emerged onresource-conserving agriculture (Shaxson, 1988; Hudson, 1992;Pretty, 1995; Hurni, 1996). It calls for the introduction ofparticipatory methods of decision-making and implementationthat emphasize training and capacity building and ensure high levelsof voluntary engagement by those who should have a stake in whatis done. This approach acknowledges many of the social and politicaldrivers of land degradation and recognizes that indigenous skills andthe innovative capacity of smallholders represent a vital localizedresource for managing and conserving land.

Importantly, and particularly relevant to water productivity atthe field scale, new studies have shown that it is possible topreserve and restore resources while simultaneously boostingagricultural production, using resource-conserving farming tech-nologies (Pretty et al., 2006). Noble et al. (2006) compiled evidenceof productivity intensification in 438 recent cases from 57countries across 11 million farms covering 32 million ha(Table 1). Productivity increases, based on the introduction ofresource-conserving farming technologies, were demonstratedacross a wide range of farming systems and innovations. Thesecases show that it is not necessary to trade off resourceconservation to achieve increased production. Of note is that thearea of greatest impact was found in smallholder agriculturalsystems, approximately 100% and over 150% average yield increasein smallholder rainfed systems and smallholder irrigated systems,respectively (Table 1), and the greatest relative yield increaseswere achieved where original yield levels were very low, less than1.5 metric t/ha (Fig. 3; Noble et al., 2006).

Investing in improved land management, such as withresource-conserving technologies, can considerably improve on-farm water productivity in both rainfed and irrigated agricultural

ies and practices on 438 projects in 57 countries.

r resource-conserving agriculture Average increase in crop yieldsb (%)

169.8 (�197.2)

21.9 (�32.3)

129.3 (�167.3)

112.3 (�122.3)

98.6 (�95.3)

55.3 (�32.4)

62.0 (�28.3)

158.8 (�98.6)

156.4

atin America.

y managing land: Addressing land degradation to improve wateri:10.1016/j.agwat.2008.12.001

Fig. 3. Changes to crop yields with agricultural sustainability technologies and

practices were greatest where initial yields were smallest (360 crop yield changes in

198 projects). Source: Pretty et al. (2006).

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systems (Bossio et al., 2008). Resource-conserving agriculturecovers a broad range of systems which have the potential toimprove water productivity and water management in a variety ofways (Table 2). For example, soil management practices to improveinfiltration and soil water storage (such as zero till) can boost wateruse efficiency by an estimated 25–40%, while nutrient manage-ment can boost water use efficiency by 15–25% (Hatfield et al.,2001). Water productivity improvement can range from 70 to 100%in rainfed systems and from 15 to 30% in irrigated systems usingresource-conserving agricultural techniques that enhance soilfertility and reduce water evaporation (Table 3; Pretty et al., 2006).Water productivity can be improved by implementing better

Table 2Resource-conserving agricultural practices increase water productivity and enhance ot

Resource-conserving practicesa

Organic farming, where artificial additions to the farming system (inorganic fertilizers

and agrochemicals) are avoided, and soil organic matter is increased

Conservation agriculture, which combines non-inversion tillage (minimum or zero

tillage in place of plowing) with mulching or cover cropping and crop rotation

Ecoagriculture, which emphasizes managing agricultural landscapes to enhance

production while conserving or restoring ecosystem services and biodiversity

Agroforestry, which incorporates trees into agricultural systems and stresses the

multifunctional value of trees within those systems

Integrated pest management, which uses ecosystem resilience and diversity for pest,

disease, and weed control and seeks to use pesticides only when other options

are ineffective

Integrated nutrient management, which seeks both to balance the need to fix nitrogen

within farm systems with the need to import inorganic and organic sources of

nutrients and to reduce nutrient losses through erosion control

Integrated livestock systems, especially those that incorporate stall-fed dairy cattle,

small stock, and poultry, which raise overall productivity, diversify production,

use crop by-products, and produce manure

Aquaculture, which brings fish, shrimp, and other aquatic resources into farm

systems – irrigated rice fields and fishponds – and increases protein production

Water harvesting in dryland areas, which maximizes the use of scarce rainfall by

capturing runoff (and sediments) for productive purposes

Water saving irrigation, including small scale micro-irrigation and reduced-water

rice production to increase returns to applied water and diversify smallholder

farming systemsa Resource-conserving agriculture covers farming systems that aim to conserve natural

diversification, plant and animal integration, and an emphasis on soil quality, especially

practices are often adopted in an integrated system.b Benefits from integrated systems are multiple, listed here are one or two of the prim

chapter.

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), doi

adapted cropping systems, particularly in semi-arid environments(Hatfield et al., 2001), Examples (Noble et al., 2006; Pretty et al.,2006) suggest that improved land management is one of the mostpromising ways of increasing on-farm water productivity in low-yielding rainfed systems (Falkenmark and Rockstrom, 2004).

4.3. Enhancing the multifunctionality of agricultural landscapes

Enhancing the multifunctionality of agricultural landscapesmeans increasing the types of ecosystem services derived orsupported by the landscape, while maintaining agriculturalproduction as a primary function. Most relevant to watermanagement is getting the most possible benefit from waterused, and maintaining regulatory and supporting ecosystemservices that maintain water supplies.

Multifunctionality can be enhanced at both farm and landscapescales. On-farm diversification, as in many resource-conservingfarming systems, is one way to diversify livelihoods, reducevulnerability, and achieve other ecosystem benefits, such as carbonsequestration (Pretty et al., 2006). This improves water produc-tivity at the farm scale by introducing a wider diversity ofproductive elements to get greater return to water used. Thesemultiple elements may include cash crops, niche crops or livestockand fisheries (Molden et al., 2007).

Landscape approaches that go beyond farm scale are alsonecessary because land degradation has causes and impacts beyondthe location where it is observed. Land degradation often arisesbecause of the failure to integrate the agroecological system into thebroader landscape. Vital ecosystem functions, particularly related towater cycling, cannot be maintained without a larger scale approachwithin an ecosystem context. Landscape approaches take intoaccount the ecology and function of the landscape’s components and

her water related ecosystem services.

Primary water benefitb

Increased soil water holding capacity

Reduced evaporation

Reduced runoff and erosion

Increased regulating and supporting water related ecosystem services

Multiple water uses increase water productivity

Increased regulating and supporting water related ecosystem services

Reduced water pollution

Increased water productivity by reducing nutrient constraints

Multiple water uses increase water productivity

Multiple water uses increase water productivity

Reduced unproductive losses of water

Reduced runoff and erosion

Reduced unproductive losses of water

Increased water productivity

resources and minimize negative environmental impacts. Approaches include plant

soil organic matter, and on biological solutions to fertility and pest control. Multiple

ary benefits related to specific land degradation and water issues highlighted in this

y managing land: Addressing land degradation to improve water:10.1016/j.agwat.2008.12.001

Table 3Changes in water productivity from the adoption of sustainable agricultural

practices in 144 projects, by crop type (kg of produce per m3 of water used).

Crop Before

intervention

After

intervention

Gain Increase (%)

Irrigated agriculture

Rice (18 projects) 1.03 (�0.52) 1.19 (�0.49) 0.16 (�0.16) 15.5

Cotton (8 projects) 0.17 (�0.10) 0.22 (�0.13) 0.05 (�0.05) 29.4

Rainfed agriculture

Cereals (80 projects) 0.47 (�0.51) 0.80 (�0.81) 0.33 (�0.45) 70.2

Legumes (19 projects) 0.43 (�0.29) 0.87 (�0.68) 0.44 (�0.47) 102.3

Roots and tubers

(14 projects)

2.79 (�2.72) 5.79 (�4.04) 3.00 (�2.43) 107.5

Note: Numbers in parentheses are standard errors. Source: Pretty et al. (2006).

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make strategic use of their potential, integrating agriculture into anecosystematic whole (Ryszkowski and Jankowiak, 2002). Thus, forexample, natural zones of deposition are maintained to capturewater and sediments, wetlands preserved to provide water storage,filtering and buffering of stream flow, and woodlots and forestpatches placed strategically to provide wind break and microcli-matic control (Ryszkowski and Kedziora, 2008). In addition, viewingagriculture at landscape levels improves opportunities for managingagriculture and land at these scales.

At the landscape level, there are several ways to increasemultifunctionality. One way is to actively manage non-farmed landin and around farmed land. This includes wasteland and riparianzones. In a system widespread in the Eastern Himalayas, riparianzones become productive parts of the landscape, protecting steephillsides and river banks from accelerated erosion (Zomer andMenke, 1993). Another way is to make greater use of opportunitiesto substitute perennials for annuals (especially for livestock feed andoils), which can also generate new income-earning potential. Theseapproaches may be the best option for sustainable production ondegradation-prone lands (Scherr and McNeely, 2008). Using moreperennials, it should be noted, will also typically boost local waterconsumption through increased evapotranspiration.

5. Conclusion

This paper has detailed the strong links between landdegradation and water use and management. It demonstratesthat improved land management can be good for both agriculturallivelihoods and water resources simultaneously. It makes clearthat mitigation of land degradation can result in significantincreases in water productivity, and this can be achieved usingexisting technologies and approaches. The need for more food overthe next 50 years calls for agricultural intensification, and thegrowth of more food with less water. In order to achieve this goal,land degradation must be mitigated. The paper calls for policy andlocal-level interventions that can stimulate resource-conservingagriculture that improves land and water productivity, and workswith ecosystem sustainability and contributes to it in the longterm. In addition, the paper calls for an understanding of land useat the landscape level, managing these as a suite of potentialactivities with ecosystems in common.

Acknowledgements

This paper is a product of the Comprehensive Assessment ofWater Management in Agriculture (CA). The CA is a 5-yearinitiative to analyze the benefits, costs, and impacts of the past 50years of water development and management in agriculture, toidentify present and future challenges, and to evaluate possiblesolutions. The main Assessment report: Water for Food, Water for

Life: A Comprehensive Assessment of Water Management in

Please cite this article in press as: Bossio, D., et al., Managing water bproductivity and rural livelihoods. Agric. Water Manage. (2009), do

Agriculture is published by Earthscan (2007). More on the CAdonors, co-sponsors (CBO, CGIAR, FAO, Ramsar), and publicationscan be found at: http://www.iwmi.cgiar.org/assessment. KimGeheb’s input into this paper was supported by the CGIARChallenge Program on Water and Food. Significant contributions tothe assessment were made by: Pranita Bhushan, Jon Hellin, GunnarJacks, Annette Kolff, Godert van Lynden, Bancy Mati, FreddyNachtergaele, Constance Neely, Don Peden, Jorge Rubiano, GemmaShepherd, Christian Valentin, and Markus Walsh.

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