AMBI02012,41:370-379 D0110.1007/s13280-012-0249-6 REVIEW PAPER Agricultural Non-Point Source Pollution in China: Causes and Mitigation Measures Bo Sun,Linxiu Zhang,Linzhang Yang,Fusuo Zhang,David Norse, Zhaoliang Zhu Received:28 September 2010/Revised:31 December 2011/Accepted:12 January 2012/Published online:5 February 2012 Abstract Non-point source (NPS)pollution has been now the largest user of synthetic nitrogen fertilisers in the increasingly serious in China since the 1990s.The increases world.However,this agro-chemical-based intensive agri- of agricultural NPS pollution in China is evaluated for the culture has contributed substantially to the emission of the period 2000-2008 by surveying the literature on water and very powerful greenhouse gases CH,and N2O,and the entry soil pollution from fertilizers and pesticides,and assessing of pollutants(excessive nitrogen and phosphorus,pesticide the surplus nitrogen balance within provinces.The main and heavy metals)into water bodies and soils(Smil 1997). causes for NPS pollution were excessive inputs of nitrogen These pollutants have adverse effects on environmental fertilizer and pesticides,which were partly the result of the quality and public health,for example,eutrophication of inadequate agricultural extension services and the rapid lakes and streams,soil contamination by heavy metals and expansion of intensive livestock production with little of the accumulation of pesticide residues in food. waste management.The annual application of synthetic The response to these problems since the 1960s has been nitrogen fertilizers and pesticides in China increased by to shift agricultural policies and R&D programmes towards 50.7 and 119.7%,respectively,during 1991-2008.The a more sustainable growth path.This has led to the devel- mitigation measures to reduce NPS pollution include:cor- opment of many new techniques and integrated resource rect distortion in fertilizer prices;improve incentives for the management practices that can mitigate the adverse effects recycling of organic manure;provide farmers with better of intensive farming on the environment (Conway 1994, information on the sound use of agro-chemicals;and tighten 1997).However,controlling NPS pollution at the regional, the regulations and national standards on organic waste national and local scale is a complex and difficult problem disposal and pesticides use. which can take decades to overcome,for example,reduc- tion of nitrate pollution in the EU.This study analyses the Keywords Non-point source pollution. reasons for increasing NPS pollution in China,then put Synthetic nitrogen fertilizers.Organic manure. forwards mitigation measures for NPS pollution control that Agricultural policy.Mitigation strategy are primarily for crop production and need to be comple- mented by other measures to control NPS pollution from the livestock sector. INTRODUCTION China is facing the challenge of feeding her large and STATUS OF NON-POINT SOURCE POLLUTION increasing population with a limited and decreasing culti- FROM CROP PRODUCTION IN CHINA vated land while achieving a clean and safe environment(Fu 2008).After the onset of the green revolution in the 1950s, Water Pollution from Crop Fertilization increasing inputs of inorganic fertilisers,organic manures and pesticides became the principal means globally and in Water bodies in China have become seriously polluted China of attaining high-crop yields and,indirectly,greater since the 1990s and there have been no marked improve- livestock production(FAO 2008).Consequently,China is ments in recent years.China has 4880 lakes,covering a Royal Swedish Academy of Sciences 2012 Springer www.kva.se/en
REVIEW PAPER Agricultural Non-Point Source Pollution in China: Causes and Mitigation Measures Bo Sun, Linxiu Zhang, Linzhang Yang, Fusuo Zhang, David Norse, Zhaoliang Zhu Received: 28 September 2010 / Revised: 31 December 2011 / Accepted: 12 January 2012 / Published online: 5 February 2012 Abstract Non-point source (NPS) pollution has been increasingly serious in China since the 1990s. The increases of agricultural NPS pollution in China is evaluated for the period 2000-2008 by surveying the literature on water and soil pollution from fertilizers and pesticides, and assessing the surplus nitrogen balance within provinces. The main causes for NPS pollution were excessive inputs of nitrogen fertilizer and pesticides, which were partly the result of the inadequate agricultural extension services and the rapid expansion of intensive livestock production with little of waste management. The annual application of synthetic nitrogen fertilizers and pesticides in China increased by 50.7 and 119.7%, respectively, during 1991-2008. The mitigation measures to reduce NPS pollution include: correct distortion in fertilizer prices; improve incentives for the recycling of organic manure; provide farmers with better information on the sound use of agro-chemicals; and tighten the regulations and national standards on organic waste disposal and pesticides use. Keywords Non-point source pollution Synthetic nitrogen fertilizers Organic manure Agricultural policy Mitigation strategy INTRODUCTION China is facing the challenge of feeding her large and increasing population with a limited and decreasing cultivated land while achieving a clean and safe environment (Fu 2008). After the onset of the green revolution in the 1950s, increasing inputs of inorganic fertilisers, organic manures and pesticides became the principal means globally and in China of attaining high-crop yields and, indirectly, greater livestock production (FAO 2008). Consequently, China is now the largest user of synthetic nitrogen fertilisers in the world. However, this agro-chemical-based intensive agriculture has contributed substantially to the emission of the very powerful greenhouse gases CH4 and N2O, and the entry of pollutants (excessive nitrogen and phosphorus, pesticide and heavy metals) into water bodies and soils (Smil 1997). These pollutants have adverse effects on environmental quality and public health, for example, eutrophication of lakes and streams, soil contamination by heavy metals and the accumulation of pesticide residues in food. The response to these problems since the 1960s has been to shift agricultural policies and R&D programmes towards a more sustainable growth path. This has led to the development of many new techniques and integrated resource management practices that can mitigate the adverse effects of intensive farming on the environment (Conway 1994, 1997). However, controlling NPS pollution at the regional, national and local scale is a complex and difficult problem which can take decades to overcome, for example, reduction of nitrate pollution in the EU. This study analyses the reasons for increasing NPS pollution in China, then put forwards mitigation measures for NPS pollution control that are primarily for crop production and need to be complemented by other measures to control NPS pollution from the livestock sector. STATUS OF NON-POINT SOURCE POLLUTION FROM CROP PRODUCTION IN CHINA Water Pollution from Crop Fertilization Water bodies in China have become seriously polluted since the 1990s and there have been no marked improvements in recent years. China has 4880 lakes, covering a 123 Royal Swedish Academy of Sciences 2012 www.kva.se/en AMBIO 2012, 41:370–379 DOI 10.1007/s13280-012-0249-6
AMBI02012,41:370-379 371 A Seven main river systems B Twenty-eight major lakes 100% 100% 80% 80% ▣Grade V plus Bnb 60% 60% ▣Grade IV-V 40% 40% Grade I-mI 200 20% 0% 0% 2000 00 2000 1008 Year Year Fig.1 Water quality in (a)seven main river basins and (b)28 major lakes (in different grades) total area of 83 400 km2 and accounting for 0.8%of the The national groundwater resources assessment in 2000- country.According to an evaluation of eutrophication in 2002 showed less than 5%of the total resources of 131 major lakes in 2000,about 50%of them were eutro- 350 thousand million m'per year suffered from serious phic (Yuan 2000).and for 75%of these lakes the eutro- pollution,so most of it could be used in agriculture and phication is getting worse.Over half of the rivers and about industry after the conventional treatment.The shallow two-thirds of the lakes in the seven river systems and 28 groundwater resources polluted by nitrate are mainly in the major lakes were assessed to be of poor quality (Grade IV North China Plan.the Northeast Plain.the Jianghan Plain and above')during 2000-2008 (Fig.1)(SEPA 2000- (in the middle reach of Yangtze River)and the Yangtze 2008).Lake eutrophication has been showing a rapidly Delta region (Zhang and Li 2004). increasing trend since 2000,with serious algal bloom crisis Projections suggest that the future nitrogen surplus from in Dianchi Lake in 2001 and in Taihu Lake in 2007(Qin crop production will increase from about 154 kg ha in et al.2007;Gao and Zhang 2010).Nitrogen concentrations 2004 to 179 kg ha in 2015,and hence the risk of non- in large rivers,especially the Yangtze and Yellow river, point source pollution will increase (Shen et al.2005). have been increasing in recent years (Li et al.2007;Yu During 2005-2008,the high-risk area for fertilizer appli- et al.2010).The estuaries and coastal water near cities are cation included five coastal provinces and three munici- seriously polluted,and the annual frequency of red tides palities in the east region and four provinces in middle has increased from 28 in 2000 to 68 in 2008 with a region.There will be three more provinces (Hainan,Anhui cumulative area of 13,738 km2(SEPA 2000-2008). and Hebei)and one municipality (Chongqing)facing high The NPS problem is not restricted to surface water risks in 2020 if current policies and trends continue bodies.The shallow groundwater in intensive vegetable (Fig.2). growing areas generally suffers from very serious nitrate pollution.A survey of 16 counties in the Yangtse Delta Pollution from Pesticides region (i.e.Jiangsu Province,Zhejiang Province and Shanghai City)found 38%of the drinking water wells had Long-term intensive application of pesticide has caused a nitrate-N content 20 mg L-(Zhang 1999).Another contamination of soil,surface water,groundwater and farm survey of 14 counties in three cities in North China(i.e. products.In the period 1950-1983,soil pollution was Beijing,Tianjin and Tangshan)found that 50%of the mainly caused by organochlorine pesticides (OCPs),with a sampling sites had nitrate-N levels>11.3 mg L-(the total consumption of 4.46 Mt of Lindane (HCH)and 0.435 Europe Union limit for drinking water)in nitrate-N con- Mt of dichlorodiphenyltrichloroethane(DDT)in 33 years tent-the highest reached 68 mg L(Zhang et al.1996). Conventional treatment for water includes physical and biological IThere are five grades in the national environmental quality treatments.The solid pollutants are removed first by sand sedimen- standards for surface water (MEP 2002).There are 24 items to tation;then the colloidal and dissolved organic pollutants (BOD. evaluate the water quality.such as pH,COD,BOD.N,P,heavy COD)are removed by biological treatment including the biological metal,petroleum,Faecal Coliform Bacteria,etc.From Grades I to IV, filter biofilm,biological dial,bio-contact oxidation and fluidized bed. the threshold value for total N is 0.2.0.5.1.0,1.5 and 2.0 mg L-, Advanced treatment is to remove the refractory organic matter, respectively.The standards also set limits for the content of different nitrogen and phosphorus by biological nutrient removal,coagulation pesticide in surface water with the highest value of 0.08 mg L-for precipitation,sand filtration,activated carbon adsorption,ion dimethoate. exchange and electrodialysis method. Royal Swedish Academy of Sciences 2012 www.kva.se/en ②Springer
total area of 83 400 km2 and accounting for 0.8% of the country. According to an evaluation of eutrophication in 131 major lakes in 2000, about 50% of them were eutrophic (Yuan 2000), and for 75% of these lakes the eutrophication is getting worse. Over half of the rivers and about two-thirds of the lakes in the seven river systems and 28 major lakes were assessed to be of poor quality (Grade IV and above1 ) during 2000-2008 (Fig. 1) (SEPA 2000- 2008). Lake eutrophication has been showing a rapidly increasing trend since 2000, with serious algal bloom crisis in Dianchi Lake in 2001 and in Taihu Lake in 2007 (Qin et al. 2007; Gao and Zhang 2010). Nitrogen concentrations in large rivers, especially the Yangtze and Yellow river, have been increasing in recent years (Li et al. 2007; Yu et al. 2010). The estuaries and coastal water near cities are seriously polluted, and the annual frequency of red tides has increased from 28 in 2000 to 68 in 2008 with a cumulative area of 13,738 km2 (SEPA 2000-2008). The NPS problem is not restricted to surface water bodies. The shallow groundwater in intensive vegetable growing areas generally suffers from very serious nitrate pollution. A survey of 16 counties in the Yangtse Delta region (i.e. Jiangsu Province, Zhejiang Province and Shanghai City) found 38% of the drinking water wells had a nitrate–N content[20 mg L-1 (Zhang 1999). Another survey of 14 counties in three cities in North China (i.e. Beijing, Tianjin and Tangshan) found that 50% of the sampling sites had nitrate–N levels[11.3 mg L-1 (the Europe Union limit for drinking water) in nitrate–N content—the highest reached 68 mg L-1 (Zhang et al. 1996). The national groundwater resources assessment in 2000- 2002 showed less than 5% of the total resources of 350 thousand million m3 per year suffered from serious pollution, so most of it could be used in agriculture and industry after the conventional treatment.2 The shallow groundwater resources polluted by nitrate are mainly in the North China Plan, the Northeast Plain, the Jianghan Plain (in the middle reach of Yangtze River) and the Yangtze Delta region (Zhang and Li 2004). Projections suggest that the future nitrogen surplus from crop production will increase from about 154 kg ha-1 in 2004 to 179 kg ha-1 in 2015, and hence the risk of nonpoint source pollution will increase (Shen et al. 2005). During 2005-2008, the high-risk area for fertilizer application included five coastal provinces and three municipalities in the east region and four provinces in middle region. There will be three more provinces (Hainan, Anhui and Hebei) and one municipality (Chongqing) facing high risks in 2020 if current policies and trends continue (Fig. 2). Pollution from Pesticides Long-term intensive application of pesticide has caused contamination of soil, surface water, groundwater and farm products. In the period 1950-1983, soil pollution was mainly caused by organochlorine pesticides (OCPs), with a total consumption of 4.46 Mt of Lindane (HCH) and 0.435 Mt of dichlorodiphenyltrichloroethane (DDT) in 33 years Fig. 1 Water quality in (a) seven main river basins and (b) 28 major lakes (% in different grades) 1 There are five grades in the national environmental quality standards for surface water (MEP 2002). There are 24 items to evaluate the water quality, such as pH, COD, BOD, N, P, heavy metal, petroleum, Faecal Coliform Bacteria, etc. From Grades I to IV, the threshold value for total N is 0.2, 0.5, 1.0, 1.5 and 2.0 mg L-1 , respectively. The standards also set limits for the content of different pesticide in surface water with the highest value of 0.08 mg L-1 for dimethoate. 2 Conventional treatment for water includes physical and biological treatments. The solid pollutants are removed first by sand sedimentation; then the colloidal and dissolved organic pollutants (BOD, COD) are removed by biological treatment including the biological filter biofilm, biological dial, bio-contact oxidation and fluidized bed. Advanced treatment is to remove the refractory organic matter, nitrogen and phosphorus by biological nutrient removal, coagulation precipitation, sand filtration, activated carbon adsorption, ion exchange and electrodialysis method. AMBIO 2012, 41:370–379 371 Royal Swedish Academy of Sciences 2012 www.kva.se/en 123
372 AMBI02012.41:370-379 2005-2008 2020 Risk class Low Potential High Fig.2 Evaluation of the risk of NPS pollution within province from and livestock manure,and biological N fixation by legumes.The N excess nitrogen application during 2005-2008 and in 2020.The risk output is the crop N export by harvest.The potential and high-risk of NPS pollution is evaluated by annual surface nitrogen balances regions in China were identified as those with more than 100 and which is the difference between N inputs and outputs for the agro- 180 kg ha-of surface N balance surplus,respectively.The N surplus ecosystems within the province.The N inputs include synthetic single is projected by non-seasonal Box-Jenkins model and compound N fertilizers,crop straw returned to the field,human before they were banned in 1983.About 14 million ha of REASONS FOR NON-POINT SOURCE POLLUTION farmland suffered from OCPs pollution in 1985,with a FROM CROP PRODUCTION IN CHINA residual amount of 0.181-0.254 and 0.222-0.273 mg kg- for HCHs and DDTs in the surface soil,respectively(first Huge Losses of Inorganic N Fertilizers grade limitation is <0.05 mg kg-in National Soil Envi- from Cropland to Surface Waters ronmental Quality Standards,GB15618-1995)(Lin et al. 2000).NPS pollution from pesticides is still serious in many China's consumption of synthetic fertilizers has been regions although residue levels have declined since 1983. increasing year by year since the early 1960s to feed her The average concentrations of DDTs and HCHs were huge population from a limited area of cropland(Fig.3); 60 ug kg-1 (ND3 ~2910 ug kg-)and 8.7 ug kg-1 (ND however,the growth of crop yields has slowdown since 131 ug kg)in 2000s,respectively.The regional dif- 1990(EOCSSB 2009).China is now the largest producer ferences were very large.The average concentration of and consumer of synthetic N fertilizer in the world.Total DDTs in the soils of East China was 14-and 5-fold of that of fertilizer consumption reached 52 million tonnes in 2008. South and Southwest China,while the ones of HCHs in that is,over one-third of world consumption.The national South and Southwest China were 4-and 2-fold of those in average annual application rate is about 230 kg N ha- North China (Cai et al.2008). cropland,which is the third highest in the world after A survey during 2003-2004 of 217 reservoirs and 406 Korea and Japan.In some provinces,the average is greater rivers and lakes in seven major river basins revealed that than 400 kg N ha-and in some counties over 1000 kg surface waters in China also suffered from moderate pol- N ha for the vegetable lands. lution by OCPs (Gao et al.2008).Lindane (y-HCH)and Fertilizer use efficiency of inorganic N fertilizer has p.p'-DDT were detected in 84 and 63%of sites,with a been decreasing in China since the 1980s.The recovery mean concentration of 0.0313 ug L-1 (ND ~0.860 ratio of N in the harvest crop decreased from 57%in 1979 ug L-)and 14.6 ug L-(ND ~0.368 ug L),respec-to 43%in 1998,and the total loss of N increased by about tively.The concentrations of HCH in the rivers of northern two times (Wu 2005).This decline in nitrogen use effi- China were usually higher than those of southern China. ciency has continued since 1998 and now is an issue for The surface water with the highest concentrations of HCH almost all cereal and vegetable crops and some tree crops. and p,p'-DDT occurred mainly in the Yellow River and The national survey of pollution sources in 2007 showed Huaihe River basins. that the total nitrogen loss from cropland was about 1 600 000 tonnes,in which some 320 000 tonnes was from sur- 3 ND=Not detected at or above the method detection limit. face runoff and >200 000 tonnes from underground Royal Swedish Academy of Sciences 2012 Springer www.kva.se/en
before they were banned in 1983. About 14 million ha of farmland suffered from OCPs pollution in 1985, with a residual amount of 0.181-0.254 and 0.222-0.273 mg kg-1 for HCHs and DDTs in the surface soil, respectively (first grade limitation is \0.05 mg kg-1 in National Soil Environmental Quality Standards, GB15618-1995) (Lin et al. 2000). NPS pollution from pesticides is still serious in many regions although residue levels have declined since 1983. The average concentrations of DDTs and HCHs were 60 lg kg-1 (ND3 *2910 lg kg-1 ) and 8.7 lg kg-1 (ND *131 lg kg-1 ) in 2000s, respectively. The regional differences were very large. The average concentration of DDTs in the soils of East China was 14- and 5-fold of that of South and Southwest China, while the ones of HCHs in South and Southwest China were 4- and 2-fold of those in North China (Cai et al. 2008). A survey during 2003–2004 of 217 reservoirs and 406 rivers and lakes in seven major river basins revealed that surface waters in China also suffered from moderate pollution by OCPs (Gao et al. 2008). Lindane (c-HCH) and p,p0 -DDT were detected in 84 and 63% of sites, with a mean concentration of 0.0313 lg L-1 (ND *0.860 lg L-1 ) and 14.6 lg L-1 (ND *0.368 lg L-1 ), respectively. The concentrations of HCH in the rivers of northern China were usually higher than those of southern China. The surface water with the highest concentrations of HCH and p,p0 -DDT occurred mainly in the Yellow River and Huaihe River basins. REASONS FOR NON-POINT SOURCE POLLUTION FROM CROP PRODUCTION IN CHINA Huge Losses of Inorganic N Fertilizers from Cropland to Surface Waters China’s consumption of synthetic fertilizers has been increasing year by year since the early 1960s to feed her huge population from a limited area of cropland (Fig. 3); however, the growth of crop yields has slowdown since 1990 (EOCSSB 2009). China is now the largest producer and consumer of synthetic N fertilizer in the world. Total fertilizer consumption reached 52 million tonnes in 2008, that is, over one-third of world consumption. The national average annual application rate is about 230 kg N ha-1 cropland, which is the third highest in the world after Korea and Japan. In some provinces, the average is greater than 400 kg N ha-1 and in some counties over 1000 kg N ha-1 for the vegetable lands. Fertilizer use efficiency of inorganic N fertilizer has been decreasing in China since the 1980s. The recovery ratio of N in the harvest crop decreased from 57% in 1979 to 43% in 1998, and the total loss of N increased by about two times (Wu 2005). This decline in nitrogen use effi- ciency has continued since 1998 and now is an issue for almost all cereal and vegetable crops and some tree crops. The national survey of pollution sources in 2007 showed that the total nitrogen loss from cropland was about 1 600 000 tonnes, in which some 320 000 tonnes was from surface runoff and [200 000 tonnes from underground Fig. 2 Evaluation of the risk of NPS pollution within province from excess nitrogen application during 2005–2008 and in 2020. The risk of NPS pollution is evaluated by annual surface nitrogen balances which is the difference between N inputs and outputs for the agroecosystems within the province. The N inputs include synthetic single and compound N fertilizers, crop straw returned to the field, human and livestock manure, and biological N fixation by legumes. The N output is the crop N export by harvest. The potential and high-risk regions in China were identified as those with more than 100 and 180 kg ha-1 of surface N balance surplus, respectively. The N surplus is projected by non-seasonal Box-Jenkins model 3 ND = Not detected at or above the method detection limit. 372 AMBIO 2012, 41:370–379 123 Royal Swedish Academy of Sciences 2012 www.kva.se/en
AMBI02012,41:370-379 373 Fig.3 Grain production and 600 30 synthetic fertilizer consumption in China from 1949 to 2008 oGrain production 500 N 25 OP 400 在K 20 300 15 200 o 100 ooooocooooooooxoooocooo 4444 V9K376000020090000020086444444444444443394444 0 1949 1959 1969 1979 1989 1999 2009 Year Table 1 Estimated N output from synthetic fertilizer N in three main river valleys in China in 1995 River name Major regime Nitrogen loss in river valley (million tonnes) Length Drainage Annual flow Denitrification in N transported NH Total loss (km) area (km) (108m) agricultural soils into water bodies volatilization Yangtze River 6300 1808500 9513 1.77-2.61 2.87 1.32 5.96-6.80 Yellow River 5464 752443 661 0.24-0.53 0.65 0.17 1.06-1.35 Pearl River 2214 453690 3338 0.39-0.49 0.62 0.29 1.30-1.40 leaching.The total phosphorus loss was much less at about Rapid Development of Intensive Livestock 108 000 tonnes (MEP et al.2010).Estimates based on field Production with Limited Treatment of Organic observations on the use of the main nitrogen fertilizers Wastes (urea,ammonium bicarbonate and ammonium sulphate)for the main cereal crops(rice,wheat and maize)and the key Intensive livestock production has developed rapidly in food production provinces of China(Zhu et al.1997;Zhu China during the last two decades (Fig.4)(EOCSSB and Chen 2002)indicated that in the 1990s the total loss of 2009),leading to the generation of large amounts of nitrogen fertilizer from crops to the environment was about organic wastes but the use of these wastes for the pro- 19.1%,of which 5%entered the surface water by runoff, duction of organic fertilizer has received little attention.In 2%passed down to the groundwater by leaching,1.1% 2007,livestock and poultry farms produced 243 mil- entered the atmosphere through denitrification process lion tonnes of organic waste and 163 million tonnes of (largely in the form of N2O)and 11%through ammonia urine;the total N and P discharge from animal excretion (NH3)volatilization process.These national averages hide reached 1 024 800 and 160 400 tonnes,respectively (MEP considerable regional and cropping system variation in N et al.2010).The N and P discharge in 2007 coming from losses to the environment (Table 1)(Xing and Zhu 2002). human excreta of residents and livestock was larger than For example,leaching losses can be far greater in the high- that from inorganic fertilizers application and has become rainfall areas of southern China,and from irrigated inten- the main cause of NPS in China.This happened because sive vegetable production,and are still increasing.A the lack of national waste discharge standards has led to no review of research on urea utilization efficiency showed or inadequate waste disposal or treatment facilities in 90% that the average N leaching rate in North China was 2.1 and 2.7%of the total urea-N applied for upland and paddy field, respectively,while in South China it was 8.2 and 6.1% 4 The census includes 1963624 discharge sources from medium to large intensive units and do not include discharges from small (Yang and Sun 2008). producers. Royal Swedish Academy of Sciences 2012 www.kva.se/en ②Springer
leaching. The total phosphorus loss was much less at about 108 000 tonnes (MEP et al. 2010). Estimates based on field observations on the use of the main nitrogen fertilizers (urea, ammonium bicarbonate and ammonium sulphate) for the main cereal crops (rice, wheat and maize) and the key food production provinces of China (Zhu et al. 1997; Zhu and Chen 2002) indicated that in the 1990s the total loss of nitrogen fertilizer from crops to the environment was about 19.1%, of which 5% entered the surface water by runoff, 2% passed down to the groundwater by leaching, 1.1% entered the atmosphere through denitrification process (largely in the form of N2O) and 11% through ammonia (NH3) volatilization process. These national averages hide considerable regional and cropping system variation in N losses to the environment (Table 1) (Xing and Zhu 2002). For example, leaching losses can be far greater in the highrainfall areas of southern China, and from irrigated intensive vegetable production, and are still increasing. A review of research on urea utilization efficiency showed that the average N leaching rate in North China was 2.1 and 2.7% of the total urea-N applied for upland and paddy field, respectively, while in South China it was 8.2 and 6.1% (Yang and Sun 2008). Rapid Development of Intensive Livestock Production with Limited Treatment of Organic Wastes Intensive livestock production has developed rapidly in China during the last two decades (Fig. 4) (EOCSSB 2009), leading to the generation of large amounts of organic wastes but the use of these wastes for the production of organic fertilizer has received little attention. In 2007, livestock and poultry farms produced 243 million tonnes of organic waste and 163 million tonnes of urine4 ; the total N and P discharge from animal excretion reached 1 024 800 and 160 400 tonnes, respectively (MEP et al. 2010). The N and P discharge in 2007 coming from human excreta of residents and livestock was larger than that from inorganic fertilizers application and has become the main cause of NPS in China. This happened because the lack of national waste discharge standards has led to no or inadequate waste disposal or treatment facilities in 90% Fig. 3 Grain production and synthetic fertilizer consumption in China from 1949 to 2008 Table 1 Estimated N output from synthetic fertilizer N in three main river valleys in China in 1995 River name Major regime Nitrogen loss in river valley (million tonnes) Length (km) Drainage area (km2 ) Annual flow (108 m3 ) Denitrification in agricultural soils N transported into water bodies NH3 volatilization Total loss Yangtze River 6300 1 808 500 9513 1.77–2.61 2.87 1.32 5.96–6.80 Yellow River 5464 752 443 661 0.24–0.53 0.65 0.17 1.06–1.35 Pearl River 2214 453 690 3338 0.39–0.49 0.62 0.29 1.30–1.40 4 The census includes 1 963 624 discharge sources from medium to large intensive units and do not include discharges from small producers. AMBIO 2012, 41:370–379 373 Royal Swedish Academy of Sciences 2012 www.kva.se/en 123
374 AMBI02012,41:370-379 600 o ◆-Beef cattle 口-k 500 △-Goatand Sheep -0-且og (s01 △-Poultry 30 -Poultry Eggs 400 00000000 uo!l! 300 44△△44△4 200 △△△△△△ 100 ◆◆◆◆◆◆◆◆◆ 0 0 19851989 1993 1997200120052009 1985 1989 1993 1997200120052009 Year Year Fig.4 Livestock number and milk and poultry production in China from 1996 to 2008 of the animal farms of China.At the national level,the and aminoformin pesticides accounted for 67.0%of the proportion of animal wastes directly exported to water was total insecticides.Most of them were applied to vegetables, 2-8%for solid wastes and about 50%for liquid wastes in fruit trees and cereals(rice and wheat)(ECCPDR 2005). 2002 (ECCEY 2003).The national average load of poultry A large amount of pesticide enters directly into or is manure in 2002 was 4.19 t ha(based on the total crop- deposited on soil or is moved by wind drift to surface land area),with the highest environmental risk of NPS waters.The average pesticide-use efficiency was only pollution arising from this manure occurring in Shanghai, about 30%of the total pesticide applied,which was caused Henan,Tianjin and Shandong where the load >18 t ha- by the over application,inadequate spray technology and the medium level NPS risk was in Beijing,Jiangsu,Hebei, poor mixing methods(Shao and Zhao 2004).The recovery Anhui and Hunan where the average loads were between 5 of pesticide on the target plant was only 9-16%of the total and 18 t ha (Wu 2005). sprayed to the wide-row crops,such as cotton and oil seed rape (Tu et al.2003). Increasing Use of Pesticides China has been the world largest consumer of pesticides for REASONS FOR UNSUITABLE APPLICATION more than 10 years(EOCASY 2002-2009)with an annual OF FERTILIZER AND PESTICIDE application amount of 1.67 million tonnes (active ingredi- ent)in 2008(Fig.5).The average application rate of pes- The Pressure for High Levels of Food ticide in the east,middle and west part of China is 12.91, Self-Sufficiency 7.26 and 3.43 kg ha(active ingredient)in 2001, respectively,with a mean value of 8.19 kg ha(ECCPDR China is a major agricultural country with 22%of the 2005). world's population (1.3 thousand million)but only 7%of In 2000,insecticides,fungicides,herbicides and plant the cultivated land of the world.Food production has growth regulators accounted for 54.7.25.3.19.3 and 0.7%. increased substantially during the past 50 years,and this is respectively,of the total consumption (Lin et al.2000). largely because of progress in science and technology and The organo-chlorine and organo-phosphorus pesticides institutional reform.Much of the increase in grain pro- accounted for over 39.4 and 37.0%,respectively,of total duction was the result of greater use of synthetic N fertil- pesticide use.The highly poisonous organic phosphorus izers,and there is a significant correlation between the annual fertilizer application and the grain production.The s Insecticides mainly include parathion,parathion_methyl,trichlor- collectives on behalf of central government used to put fon,dichlorvos,dimethoate,omethoate,ethamidophos,isocarbophos, pressures on farmers to increase production to meet local carbamate,pyrethroid,disosultap and chlordimeform.Fungicides and national food self-sufficiency targets,and most of them mainly include copper sulphate,carbendazim,benodanil,kitazin responded by increasing fertilizer use.Since 1978,how- (EBP),iprobenfos(Kitazin P),zineb,tricyclazole and jiangangmycin. ever,when China started to open up its economy,farmers Herbicides mainly include nitrofen,butachlor,2,4-D butylate,chlor- toluron,MCPA,glyphosate,atrazine,prometryn and trifluralin. have become more involved in off-farm activities and Royal Swedish Academy of Sciences 2012 Springer www.kva.se/en
of the animal farms of China. At the national level, the proportion of animal wastes directly exported to water was 2-8% for solid wastes and about 50% for liquid wastes in 2002 (ECCEY 2003). The national average load of poultry manure in 2002 was 4.19 t ha-1 (based on the total cropland area), with the highest environmental risk of NPS pollution arising from this manure occurring in Shanghai, Henan, Tianjin and Shandong where the load [18 t ha-1 the medium level NPS risk was in Beijing, Jiangsu, Hebei, Anhui and Hunan where the average loads were between 5 and 18 t ha-1 (Wu 2005). Increasing Use of Pesticides China has been the world largest consumer of pesticides for more than 10 years (EOCASY 2002-2009) with an annual application amount of 1.67 million tonnes (active ingredient) in 2008 (Fig. 5). The average application rate of pesticide5 in the east, middle and west part of China is 12.91, 7.26 and 3.43 kg ha-1 (active ingredient) in 2001, respectively, with a mean value of 8.19 kg ha-1 (ECCPDR 2005). In 2000, insecticides, fungicides, herbicides and plant growth regulators accounted for 54.7, 25.3, 19.3 and 0.7%, respectively, of the total consumption (Lin et al. 2000). The organo-chlorine and organo-phosphorus pesticides accounted for over 39.4 and 37.0%, respectively, of total pesticide use. The highly poisonous organic phosphorus and aminoformin pesticides accounted for 67.0% of the total insecticides. Most of them were applied to vegetables, fruit trees and cereals (rice and wheat) (ECCPDR 2005). A large amount of pesticide enters directly into or is deposited on soil or is moved by wind drift to surface waters. The average pesticide-use efficiency was only about 30% of the total pesticide applied, which was caused by the over application, inadequate spray technology and poor mixing methods (Shao and Zhao 2004). The recovery of pesticide on the target plant was only 9-16% of the total sprayed to the wide-row crops, such as cotton and oil seed rape (Tu et al. 2003). REASONS FOR UNSUITABLE APPLICATION OF FERTILIZER AND PESTICIDE The Pressure for High Levels of Food Self-Sufficiency China is a major agricultural country with 22% of the world’s population (1.3 thousand million) but only 7% of the cultivated land of the world. Food production has increased substantially during the past 50 years, and this is largely because of progress in science and technology and institutional reform. Much of the increase in grain production was the result of greater use of synthetic N fertilizers, and there is a significant correlation between the annual fertilizer application and the grain production. The collectives on behalf of central government used to put pressures on farmers to increase production to meet local and national food self-sufficiency targets, and most of them responded by increasing fertilizer use. Since 1978, however, when China started to open up its economy, farmers have become more involved in off-farm activities and Fig. 4 Livestock number and milk and poultry production in China from 1996 to 2008 5 Insecticides mainly include parathion, parathion_methyl, trichlorfon, dichlorvos, dimethoate, omethoate, ethamidophos, isocarbophos, carbamate, pyrethroid, disosultap and chlordimeform. Fungicides mainly include copper sulphate, carbendazim, benodanil, kitazin (EBP), iprobenfos (Kitazin P), zineb, tricyclazole and jiangangmycin. Herbicides mainly include nitrofen, butachlor, 2,4-D butylate, chlortoluron, MCPA, glyphosate, atrazine, prometryn and trifluralin. 374 AMBIO 2012, 41:370–379 123 Royal Swedish Academy of Sciences 2012 www.kva.se/en