F

Environmental Implication of Intensive Farming Practices on North China Plain

Zhen Lin 1, Zhou Hailin 2 & Xie Gaodi 1 1 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of

Sciences, Beijing 100101 , China; 2 The Administrative Center for China's Agenda 21, Beijing 100089, China

Abstract: The current pressure on production resources of North China Plain, such as land and water to feed the growing population, necessitates the assessment of the sustainability of farming practices. This study focuses on the sustainability of farming practices related to groundwater and soil fertility management. The assessment is based on selected site-specific key indicators and their established threshold limits. The current farming practices in the study area are clearly unsustainable. Only about 6% of the surveyed farm households practice sustainable farming. The study stresses that farming practice, which is economically sustainable, should not be promoted at the cost of environment. Holistic strategies need to be developed and implemented that aim at balanced use of inputs, which satisfY both productivity and environmental concerns. Key words: sustainability indicators, threshold values, farming practices, environmental implication

1 INTRODUCTION

Growing pressure on the land of North China Plain (NCP)

- a food bowl of rhe country, has made many of the

traditional farming practices increasingly difficult to sustain,

such as manuring, composting, mulching, legume-based

rotations, field levelling and fertilizing with mud from

rivers and canals. The pressure on the farmlands has also

led to a decrease in farm sizes and shortened fallow periods.

To cope with this pressure on the land and to maintain

its fertility, farmers in the area have, over the past three

decades, adopted high-yielding, external-input driven

production technologies from the western countries to

Corresponding auchor: Zhm Lin (z.lunl@igmrr.ac.cn)

complement and replace their traditional internal-input

based production technologies and practices. At present,

crop production in the area depends heavily on irrigation

with groundwater and the application of mineral fertilizers

and pesticides. In many parts of NCP, groundwater

exploitation exceeds groundwater recharge by a factor of

up to 1.5 meters (Liu et al ., 2001). Without the application

of mineral fertilizers the country cannot sustain the food

needs of the increasing population (Cheng and Han, 1992;

Lo and Xing, 1999). Excessive use of these main inputs

has led to land degradation in many parts of the area and

has also had adverse impacts on environment. The future

of the entire rural economy and the food security of the

people in the region will be determined by the sustainability

of agriculture and an effective management of natural

resources.

The sustainability of farming practices is a function of a

number of environmental, economic, and socio­

institutional factors. To isolate the contribution to

Ch inese jou rnal of Population , Resources and Enviro nment 200; Vol. 3 No.3 11

sustainability made by these factors is extremely difficult

(Hassen, I 996; Pretty, I 996; Rigby and Caceres, 2001;

Wiren-Lehr, 200 I). There is, therefore, a need to devise

appropriate ways to measure sustainability, empirically

examine the sustainability of some well-defined cropping

systems, and to develop methods to measure externalities

that contribute to sustainability (Lynam and Herdt, 1989).

There is no universal recipe for sustainable farming practices.

The main factors that determine sustainability have to be

recognized. Quantifiable key indicators of these factors

need to be identified and measured (Rigby and Caceres,

200 I). If suitable specific indicators are selected, tt ts

possible to predict system trends (Pretty, 1996).

A common problem in the assessment of the sustainabiliry

of farming practices is the acquisition and integration of

suitable indicators that are spatially and temporally

significant. Most studies related to agricultural sustainabiliry

in the region have been confined to the exploitation of

soil and water resources (CAS, 2000). Few studies have

focused on water sutliciency and soil fertility analysis (CAS,

2000) and limited efforts have been made so far to assess

farming practices using location-specific indicators and

their threshold limits. Little is known about the effects

of particular fuming practices on environment.

For a typical agricultural area in NCP, this study attempts

to provide insight into the environmenral implications of

local farming practices. Location-specific indicators and

their identified threshold limits are used for the assessmenr.

Strategies for economically viable and conservation-orienred

crop production are recommended.

2 THE STUDY AREA

Ningjin County is located in the northeastern parr of

Dezhou District in Shandong Province in NCP. It is located

between 3T3i'and 3T50' North Latitude and 116"30'

to I I TOO' East Longitude. The county has 18 townships

with 856 villages. It has a total land area of 822 km2 and

a population of 440 000. The average population density

is 535 per km2.

The counry is a major food-production base of China,

with 80 percent of the total arable land under cereal

production. Most farms in the area are small and subsistence

based. The land is owned collectively and the per-capita

land area is about 0.10 ha. About ten different crops are

grown in the area. Winter wheat (Triticum sativum) and

summer maize (Zea mays) are the principal crops, which

occupy 75% of the total arable land, followed by cotton

( Gossypium) that occupies 18% of the total land area. The

remaining 7% of the land is used mainly for the cultivation

of vegetables such as chives (Allium schoengrasum), etc.

Less widely grown crops are peanut, sesame and sunflower.

Irrigation is widely practiced, with groundwater as the

only water source (IBNC, 2001).

Topographically the area is plain and homogeneous. The

average altitude is 15.4 meters above mean sea level. The

soils are very uniform; they are of alluvial origin and

dominantly loamy and moderately deep (SSODD, 1999).

The area has a continental monsoon climate (SBNC,

2000). It is characterized by an annual average temperature

of 12.3"C and annual precipitation of about 553 mm.

The precipitation is unevenly distributed. High rainfall

usually occurs in summer (April to September), accounting

for about 78 percent of the total annual precipitation. The

rainfall occurring between March and May accounts for

only I I o/o of the total annual rainfall. However, this is the

period most critical for crop-water demand. The rainfall

occurring from October to February has a share of only

I 0 percenr of the total rainfall, designating this period as

dry. The average evaporation is I ,319 mm, which is almost

double the annual rainfall. Declining and uneven

distribution of rainfall and high evaporation leads to an

increase in irrigation-water demand.

3 METHODOLOGY

3.1 Data collection and analysis methods

Data were collected from both secondary and primary

sources. Secondary data from statistical yearbooks and

documenrs were collected from relevanr governmenr

agencies. Primary data were collected through a household

survey, focus-group discussions (FGD), and inrerviews of

key informants, institutional surveys and field observations.

Data on current land-management practices included farming practices, amount of irrigation-water use, the use

of fertilizers and pesticides for the major crops (i.e., wheat, maize, cotton and chives), and farmers' perceptions and

knowledge of resource conservation. Four villages were

applied for the selection of household survey. A simple

random sampling method was adopted to select households for the survey. The household survey was conducted

between the first week of June and the last week of July 2002, and continued again from the first week of September until the last week of November 2001. Altogether, 270

households were interviewed.

The soil fertility status of wheat and maize fields has been

surveyed right after the harvest of maize in September.

Wheat and maize are cultivated in a cyclic way around the year. The analysis was performed on the plow layer

(i.e., 0-20 em). A total of 44 soil samples were analyzed for soil reaction (pH), soil organic matter (SOM) content,

and the contents of available nitrogen (N), phosphorus (P205) and potassium (K20). Fluctuations of the

groundwater table were analyzed using groundwater-table

data for the past 30 years obtained from the Water Survey Station of Dezhou District.

To investigate the environmental impact of current fertilizer­use practices, the nitrate contents of groundwater and

chives plants were also measured. The sample tube wells drawing water for irrigation from shallow groundwater were randomly selected. All wells have concrete casings for protection from contamination by surface water and

are fitted with electric or diesel-powered pumps. The tube

wells were pumped for about 3 minutes to remove any stagnant water before fresh water samples were collected.

A total of 20 samples were collected. All water samples were analyzed at the Irrigation Bureau of Dezhou District.

Similarly, nitrate residue in chives plants was surveyed through testing 20 chives plants taken from the fields. Samples were analyzed at the Epidemic Prevention Station of Dezhou District.

The ranking of the farmers perceptions of the environmental effects of water management was done by

weighting individual responses under different classes of occurrence as reflected by their ranks. The composite

picture of perception was obtained by computing an index

as shown below:

Index= (FIWI+ F2W2+ F3W3+ F4W4+ F5W5 + F6W6) IN (1)

Where Fl to F6 represent the frequency of responses ranked 'very high', 'high', 'medium', 'low', 'very low', and

disagreement cases, respectively. WI to W6 represent

corresponding weights applied to different ranked classes as mentioned before, specifically WI= 1.0, W2= 0.8, W3=

0.6, W4= 0.4, W5= 0.2, and W6= 0.0; and N = Sample

size = 270 Households.

3.2 Selection of indicators and threshold values

Indicators have to be based on an understanding of the pressures on the environment and the processes through which human activity induces environmental change (Crabtree and Bayfield, 1998). To detect and monitor

changes and determine trends in improvement or deterioration in groundwater and soil quality in the study

Chinese Journal of Population, Resources and Environmenr 2005 Vol. 3 No.3 13

area, key indicators need to be selected and their threshold

values established. For the study, the indicators and their

rankings were identified from published research (Zhang,

1995; Zhang, eta!., 1998; Hu, eta!., 1996) and information

given by farmers. The selected indicators and their threshold

values are crop and site-specific. These indicators cover

environmental aspects, such as depth to groundwater table,

water use efficiency (WUE), soil-quality status as

represented by soil pH, SOM content, N, P205 and 1<20

content, and nitrate (N03-) concentration in groundwater

and chives plants (Table I). The selection of these indicators

is based on the following two criteria: (I) Significance of

the indicators for the study area. The selected indicators

cover the major farming practices. (2) Practical applicability

of the indicators selected. The indicators selected are all

location specific; data for the measurement of each indicator

and the threshold values for indicator assessment are

available at the local level. The selection of the indicators

has been done in cooperation with local experts and the

farmers.

The implications and assumptions of the threshold values

for the selected indicators in relation to sustainability are:

e"Very good" and "good" mean that there is no indication

of a problem or problematic trend.

e"Fair" is the borderline condition for sustainability.

Some actions are needed to address the problem or more

detailed information should be sought to suggest how to

stop a decline in the condition.

Table 1. Threshold values for selected indicators

e"Poor" and "very poor" mean that there is indication

of a problem or problematic trend. Urgent actions are

needed to improve the condition.

4 RESULTS AND DISCUSSIONS

4.1 Groundwater management practices

In surveyed villages, groundwater is the only source of

irrigation. Each household has equal access to and share

of the groundwater resources. All irrigation systems in the

county are small-scale. They are constructed by the farmers

themselves using locally available materials and skills. The

field survey showed that well digging is not planned.

According to their felt needs, they decide where to locate

the wells and how many wells to dig. They also use the

water at their own discretion. The farmers prefer to have

their wells very close to their plots. This has led to an

increase in the number of wells in the area, from 5 872

in 1978 to I 0,180 in 2000, with an average density of 20 wells per km2. On average, each ten households own one

well, to which several pumps for water lifting may be

connected. The average distance from the wells to the field

is 120 meters, with a range between I to 500 meters.

Water is conveyed to the fields by plastic pipes. All farmers

have adopted basin irrigation. Since no fee is charged for

the groundwater, the farmers pump as much groundwater

as possible in order to meet their irrigation needs. The

• .\,·r fin)lul'iog< "" •l>ik 1/w '"t!' dl<' rlfllllll!illrd /~1 f/ui'IO_'!,t'lik s111l> ll'ith •llllil.tr 11'.\'1/tn' d<ro.f.• r/>1' .•i1111flingji;mu· 111 the _,·,unp/ing .•it c.• ofrf,j_, .•lilt()' .

. \our(t'.•: '/f>,lll,'t_. o,;/. 1998. /hmg. IY9'1. 1/u,,·t,d, /<J<J6.

14 Chinoc ]ourn.d of PopuLuion, Rnour~_t', .wd FnvironnH:nt 200') \'ol. j l'\o .. ~

quantity of groundwater actually used for irrigation is

significanrly higher (AN OVA rest, p<O.OO I) than the

recommended quantity for all the crops under study,

regardless of farm size and varieties of crops. For instance,

the recommended quantity of water for one irrigation of

wheat, maize, cotton and chives is 600-750, 525-675,

600-750 and 750-900 m-'/ha, respectively, while the actual

quantity of water used is 975, 94 5, I 005 and I 065 m3/ha,

respectively. Overuse of groundwater is encouraged by

the low irrigation cost. Groundwater charges to farmers

cover only the costs of pumping and distribution of water.

There is no "capital" charge for the water itself. Therefore,

in order to ensure crop production in a small landholding,

farmers apply as much water as possible to irrigate the

land. However, the water use efficiency (WUE) is very

low. WUE of wheat, maize and cotton is 1.26, 1.45 and

0.60 kg/m·\ respectively, which is classified as poor to very

poor (Table I).

4.2 Environmental implications of groundwater

management practices

During the field survey, farmers were asked about their

perceptions of groundwater use practices. The composite

picture of perception was obtained by computing an index

(see Eq. [I]). 'Declining groundwater table' is featured

as the most important adverse environmental effects caused

by current water management practices, followed by

'declining groundwater quality', 'increasing irrigation cost',

and 'increase soil salinity', these problems are ranked as

important dTecrs, followed by 'compacted or hardened

soil', 'increasing land subsidence' and 'creates water logging'

(Table 2). Evidence from both primary and secondary

sources has been used to support farmers' perceptions.

The statement 'declining groundwater table' has been

substantiated by farmers' observation and the trend analyses

of rhe groundwater table in the study area; 97 percent of

the farmers observed a decline of the groundwater table

by an average of I 0 m over recent years. One tenth of rhe

wells rend to dry up temporarily during summer season,

a few of these wells have been abandoned altogether.

According to groundwater-observation data from 50

shallow wells in the county, the average depth of the

groundwater table has fallen from 12.36 m in 1970 to

7.73 m in 2000, i.e., an annual water table decline of

0.21m.

Table 2 Ranking of farmers' perceptions of the adverse

environmental effects of groundwater use

.\'of('" flltl'lj>l<'f,lfiOIII/illtft'.\"/,i/111''."

fUJJ-O..!O..ot't'l"\lo/1'

O . .ll-0.·!0=/oll' 0.·11 O.(J()_,J/laliulll

O.M-fUW=I't.'!.l' 0.8/- J.(}().o

The depth of the water table varies according to the season.

It remains relatively stable (i.e., between 8.66 m and 8.72

m) between November and February, as there is nor much

demand for irrigation during that period. However, it

starts to decline sharply in April and reaches its lowest

level in May at 6.37m. These are rhe peak months for the

irrigation of winter wheat.

The roral dissolved salt content has been used as an

indicator of groundwater quality (Kandiah, 1990). For

irrigation, salt concentration should be less than 0.5 g/1

(CAS, 2000). However, the salt content of groundwater

in the area is 0.65 to 1.40 g/1. Crops irrigated with this

water should be salt tolerant, and a drainage system should

be available to EKilirare leaching. The dominant irrigated

crops are wheat (moderately salt tolerant) and maize

(moderately salt sensitive). The field survey showed that

maize yields decline. This has also been observed by the

farmers, who even term the groundwater "dangerous

water". Increasing soil salinity is also evident from white

parches that can be observed after irrigation. Irrigation

cost refers to both time and money. Over-exploitation of

groundwater results in a progressive decline in yields due

to an increase in suction lift and the drying-up of wells.

Well yields have decreased from an average 35 m·1/hr in

1965 to I 0 m-'/hr in 2000. Correspondingly, time spent

in pumping water for one hectare of cropland increased

from 22 hours in 1965 to I 05 hours in 2000. These

conditions have led to increased consumption of diesel,

electricity and labor, and hence in the overall cost of water

lifting.

Farmers' awareness of the shortage of groundwater plays

an important role in their management behavior. The

majority of the farmers (82%), regardless of the villages

and the kinds of crops cultivated, agreed that groundwater

should be used efficiently. However, they did not realize

the actual scarcity of groundwater. Their perception was

that groundwater is renewable and inexhaustible. This

perception has encouraged them to use groundwater more

intensively for short-term benefits. The farmers consider

groundwater as a free gift and use it according to their

own demand and benefit. They have not been made aware

that their water use is depleting the groundwater resources

of the area.

4.3 Soil-fertility management practices

4.3.1 Soil-fertility management practices

The farmers in the area use fertilizers very intensively to

maximize their yields. The major sources of plant nutrients

are mineral fertilizers followed by farmyard manure (FYM)

and crop residues. The mineral fertilizers used are mainly

nitrogen (N), phosphate (P205), and potassium (K20),

which are available everywhere in the area and the farmers

have the cash to purchase these fertilizers. Usually, the

top-dressing method is used for mineral fertilizer

application. The main source of FYM is the livestock

reared by households, but some FYM is also purchased.

The FYM is applied to the field during the land preparation.

The crop residue is mainly the wheat straw that is left in

the field for the following maize cultivation. Maize residues

are rarely used for the following wheat crop.

Compared with the application rates recommended by

the extension service, FYM and K20 are used in insufficient

amounts, while N and P205 are over-applied. Nitrogen

is significantly overused for all the crops studied. The

recommended application rates of N for wheat, maize,

cotton and chives are 210-255, 165-210, 195-240, and

600-750 kg/ha respectively, while the actual rates applied

by the farmers are 375, 240, 360, and 1035 kg/ha,

respectively.

16 Chinese Journal of Population, Resources and Environment 2005 VoL 3 No.3

The study revealed that the majority of farmers (65%)

prefer to use a combination of organic and mineral

fertilizers, because of the positive effect of manure on

structure, aeration and water holding capacity of the soil.

The application of FYM by farmers is limited by its

inadequate availability. The survey revealed that the farmers

do not know how to use mineral fertilizers properly. They

are not guided by the extension service in appropriate and

balanced use of fertilizers based on existing soil fertility

conditions and the nutrient requirements of the crops.

They normally apply fertilizers in together with irrigation,

increasing the leaching of nutrients into the groundwater.

Also, easy access to input markets and low prices of inputs

encourage the farmers to apply more mineral fertilizers

than actually required, particularly nitrogen and

phosphorus.

4.3.2 Nutrient status of the soil

A simple nutrient balance for the main crops grown in

the area reveals the approximate nutrient status of the

soils. The nutrient balance W<!S computed as the difference

berween inputs applied and extracted by the crop using

conversion factors developed for the area by Fan and Fen

(1999) (Table3).

Table 3 shows that there is generally a positive net balance

ofN and P205 in the soil. The highest quantities of these

nutrients were found in chives fields, followed by cotton,

wheat, and maize fields. These nutrients remain in the soil

and may be subject to leaching before the following crop

is established. Under these conditions, the application of

fertilizers is probably not economical, particularly for the

Table 3 Nutrient balance in the soil for the main crops

"Fan and Fen, 1999. Source: Fi~ld survey, 2002.

farmers who have already high to very high levels of these nutrients in their soils. However -with the exception of the chives fields-, the 1<20 balance is negative. This fact points to a possible depletion of 1<20 and thus the risk unbalanced plant nutrition. This result concurs with the observation reported before that 1<20 fertilizers are usually applied below the recommended rates. Similar results were found by studies conducted in other areas of the NCP (Xu, 2000; Huang et al., 2000).

Soil fertility as reflected by the selected indicators (i.e., SOM, N, P205, and 1<20) has improved over the past 20 years. From 1982 to 1999, SOM content increased from 0.85 to 1.16%, N content from 64 to 70 mg/kg, P205 from 7 to 15 mg/kg, and 1<20 from 108 to 123 mg/kg (SSODD, 1999). Soil pH in the study area has been assessed as fair (i.e., moderately alkaline) (Table 4), which is considered the threshold value for sustainability. Further improvement in soil pH is required for increasing production and enhancing soil fertility.

Soil organic matter (SOM) has been widely promoted as a key indicator of soil quality, particularly for agricultural soils (Nortcliff, 2002). The majority (85%) of the farms have good or very good soil organic matter levels. This can most probably be attributed to the massive return of crop residues to the fields and the increasing application of FYM. However, compared to the recommendations by the extension service, FYM applications are still insufficient.

The soil tests revealed that the average N levels were fair, covering about 60% of the sampled households; P205 levels were generally rated good, with 85% of the households in the good and very good range. Potassium

Table 4. Soil-fertility status of the farmland for the sampled

households

Bas~d on Table 1. Figures in parmth~m a" pnrmtag~s ofsampkd households. Sourct: Field survey. 2002.

levels were generally fair, with about 50% of the households. According to the selected key indicators, therefore, the current soil-management practices do not lead to nutrient depletion and soil degradation. However, there is still scope for the improvement of soil-fertility management practices, especially in relation to long-term soil-quality maintenance based on adequate organic-matter application.

4.3.3 Environmental implications of soil fertility management practices The study found that excessive use of fertilizers can cause groundwater contamination and lead to high nitrate residue in chives. Of20 groundwater samples tested, 16 had an average nitrate concentration of 115 mg/l, which is significantly higher than the threshold value of 50 mg/l. There is a significant positive relationship between nitrogen application and nitrate concentration in the groundwater (r=0.701 **, p<0.01), demonstrating that the groundwater is contaminated by nitrogen fertilizers. Also in chives, the nitrate concentration exceeds the maximum allowable level for human consumption. The significant positive correlation between nitrogen application rates and nitrate concentration (r=0.855**, p<O.Ol) indicates that over-application of nitrogen is the main cause of the contamination of chives.

The farmers in the area have not yet realized this critical situation. They believe that water contamination is only related to surface water. In their perception, the groundwater is very clean. None of the farmers are aware of the linkage between fertilizer application and nitrogen concentration in the plants. Consequently, they are not aware of the potential hazards for human health.

4.4 Pest and disease management

Pests and diseases are serious problems, which the farmers face in the area. Therefore, all farmers use pesticides, which are cheap and freely available. To be sure of the chemicals' effects, they usually apply high doses. The average application rates of pesticides are two to three times the recommended dosages. The farmers express increasing concern of human health and environmental contamination by

Chinese Journal of Populacion, Resources and Environment 2005 Vol. 3 No.3 17

Table 5 Summary of indicators and implications for sustainability

*Refl-r to lflb!e I for threshold Z'llltm ,md tmplmatonJ fOr _>ushJtntJbi!ity of respective indicators.

overuse and improper handling of pesticides. However,

they still prefer to use high doses because they still consider

the beneficial effects greater than the harmful effects. The

survey revealed that the perceived negative effects of

pesticides are headache, nausea, stomach pain, skin rash,

and the reduction of the number of natural predators in

the fields, such as frogs and cicada. Chives growers tend

to use higher doses of pesticides than others, and the

reported occurrence of health problems is also higher.

The study revealed that, out of nine initially selected

environmental indicators, five satisfied the minimum

condition for sustainability, i.e., soil pH, SOM content,

N, P205 and K20 content of the soil. The indicators that

could not meet sustainability conditions were the depth

to groundwater table, WUE, and the concentration of

nitrate in the groundwater and the chives plants. These

particular soil characteristics exceed the thresholds levels

or safe minimum standards, which were defined as fair

in this study (Table 5).

5 SALIENT FEATURES OF SUSTAINABLE AND

NON-SUSTAINABLE FARMERS

The study clearly revealed that groundwater, fertilizers

1 8 Chinese Journal of Popul.uion, Resources and Environment 2005 Vol. 3 No.3

and pesticides are the main inputs used in the farming

system, and these are also the major causes of problems

for the water and soil resources and human health. Balanced

and integrated use of inputs is considered as an appropriate

way to assure long-term productivity with sufficient

economic returns. Therefore, recommended levels of input

use based on scientific research have been proposed to the

farmers.

Based on the assumption that recommended input­

application rates practices enable sustainable farming, two

types of farmers were identified, i.e., those who follow

recommended input-application rates were classified as

sustainable farmers' (SFs) and those who do not follow

the recommendations were classified as 'non-sustainable

farmers' (NSFs). Taking wheat-maize farmers as an example,

only 16 farmers (6%) of256 farmers could be classified

as 'sustainable' (Table 6).

Table 6 shows of the 12 indicators that were examined,

six show statistically significant differences between SFs

from NSFs. SFs are younger than NSFs; they are probably

more active in learning and acquiring new knowledge and

technology, and more open to accept innovations in their

farms than the older farmers. They are also likely to be

Table 6. Salient.features of 'sustainable' and 'non-sustainable'

farmers

'P<0.05 . .. P<O.OJ (t- Tm).

Note: The indicators used for the classification of *ustainab/e'"and '"on-sustainable *formers are

groundwater use, nitrogm use and pesticide used compared with the recommmded quantities. Only

wheat and mazu rotational croppingfonners were UJed for analysis. Souru: Field survry. 2002.

more aware of the environmental effects of excessive input

use. SFs input-application rates are within the limits of

the recommended rates, i.e., lower than the rates applied

by NFSs. Soil K20 levels are higher in the fields of SFs

(98 mg/kg) than those of NSFs (86 mg/kg), implying a

better balance between the nutrients in SFs fields. SFs use

high quantities of FYM, i.e., nearly 10,000 kg/ha more

than NSFs.

6 CONCLUSIONS

The objective of this research was to assess the sustainability

of farming practices in the light of its environmental

implications. The key indicators used are highly specific

to the crops and location of the study. Feedback from the

farmers, extension workers, local and regional government

decision-makers and researchers confirmed the soundness

of these indicators.

Concerning environmental sustainability, current irrigation

practices deteriorate and deplete the groundwater resources

and increase irrigation cost. The combination of ignorant

attitudes of farmers related to the environmental effects

of their water-use practices, low overall water-use efficiencies.

In this scenario, irrigation-based crop production in the

area is unlikely to sustain for a long period. The dependence

on pesticides and their overuse and improper handling has induced serious environmental and human health

hazards. Increased use of both organic and mineral fertilizers

over the years improved soil fertility. The soil status in

general is within the borderline for sustainability implying

that the current soil-management practices do not

deteriorate the soil resources. However, overuse of mineral

fertilizers, particularly nitrogen, contaminates the

groundwater and leads to excessive nitrate levels in crops,

thus making this practice environmentally unsustainable.

Some scholars argue that organic farming or low-external­

input agriculture is sustainable while high-external input

agriculture is not sustainable (Tisdell, 1996; MacNaeidhee

and Culleton, 2000; Rossi and Nota, 2000). However,

Dahal (1996) and Rahman (1998) found that organic

farming without proper use of additional mineral fertilizers

and pesticides leads to a negative nutrient balance in the

soil, with negative impacts on environmental and

economical sustainability. On the other hand, exclusive

emphasis on yields and farm income through intensive

use of mineral fertilizers will cause environmental

degradation, also threatening the sustainability of farming

practices (Altieri, 1992). China has successfully sustained

the productivity level of wheat and rice for over 100 years

by meeting 50% of the nitrogen requirement from organic

sources. Therefore, balanced and integrated use of mineral

fertilizers together with organic fertilizers -on the basis of

soil tests- promise long-term productivity with sufficient

economic returns. For the maintenance of soil fertility on

a sustainable basis in intensively cropped areas, greater

emphasis needs to be placed on residue management and

legumes as intercrops.

According to Smith and McDonale (1998) and Wiren­

Lehr (2001), sustainability in general is vague when both

outputs and inputs increase. However, in the study area

-which is characterized by simultaneous increases in both,

input and output levels-, the unsustainability of farming

practices could be clearly revealed using crop and site­

specific indicators and threshold values.

There are a number of limitations in terms of the way the

indicators are used. Some indicators represent various

dimensions of sustainability at the same time and may, in turn, be affected by other indicators, either positively

or negatively. For the selection of key indicators, it is

Chinese Journal of Population, Resources and Environmenr 2005 Vol. 3 No.3 19

therefore very important to ensure location and site­

specificity.

Acknowledgement

The research is under the auspice of the National Natural

Science Foundation of China (C44300) and national key

project for basic research on Agricultural Environment

(2002CB 111506). The financial support for the study

from the Asian Institute ofTechnology (AIT), and the

Regional Office of the Food and Agriculture Organization

(FAO) for the Asia-Pacific Region in Bangkok is greatly

acknowledged.

20 Chinese Journal of Populalion, Resources and Environment 2005 Vol. 3 No.3