Nutrient management in the food chain of China Fusuo Zhang Lin Ma China Agricultural University Feb. 25,2014, Beijing, China-UK Workshop on Nutrient Management and Water Resource Protection

Outline  Problems and challenges  Nutrient flow in the food chain  Strategies of nutrient management

Food security issue of China is always a global concern Lester Brown

It took several hundred years to realize the dream of food sufficiency in China (Data from the Statistic Bureau of China; Demand was estimated by using average grain demand of 400 kg/capita/yr) Year Grain demand and production (M ton)Population (M)

Grain yield in China has been merely secured by much higher input of resources including fertilizer, irrigation, plastic film and pesticides. (National bureau of statistics of China, ; Zhang et al., 2011) Grain production and resources input

Relative yield(%) GHGI(kg CO 2 eq Mg -1 ) N rate (kg N ha -1 ) Africa Developed countries China Environment impact by N loss Yield response curve

Fertilizer Overuse and Misuse

Air pollution Bulk N deposition has increased from 13 kg N ha -1 in 1980s to 21 kg N ha -1 in 2000s, among which agricultural N r sources occupied ~2/3. NATURE (Liu et al., 2013)

Soil pH was decreased by 0.5 units due to overuse of N fertilizers Soil acidification

China’s eutrophied lake area reached 8700 km 2 (2007) over the last 4 decades. (China State Oceanic Administration, 2009 ） (Jin, 2009) Eutrophication (Science 2009, )

Outline Food security and fertilizer application  Nutrient flow in the food chain Strategies of nutrient management

Nutrient management in the food chain Ma Lin’s thesis

(Zhang et al., 2012)

1.7 fold 2.4 fold  N fertilizer input is 1.7 fold of crop uptake  Total N input is 2.4 fold of crop uptake （张卫峰等， 2013 ） N input and crop uptake in Chinese crop land in CCalculated by using NUFE model (Ma et al.,2010) and FAO data base

“Better Life” in China - rapid growth of animal food, fruits and vegetables The percentage of plant protein and animal protein (Ma et al., 2013, Data source: FAO)

Booming development of animal husbandry in China in the past 30 years Pig, meat cow, sheep and goat, milk cow numbers Poultry numbers Year (the Statistic Bureau of China)

Des-coupling of crop and animal production ( Wang et al., 2010)

Atmosphere N 2, NH 3, N 2 O Exports and losses Environmental Sustainability Surface waters Groundwater Erosion and runoff Leaching N Crop production （ soil accumulation ） P Animal production Food security imports Resource use efficiency Food processing Human consumption (Ma et al., 2010) Quantify nutrient flow in the food chain by a new model NUFER (NUtrient flows in Food chains, Environment and Resources use)

High N fluxes in the food chain of China House- Hold 2.8 Animal Production 7.4 Crop Production 17.3 House- Hold 3.5 Animal Production 11.0 Crop Production 28.9 House- Hold 4.1 Animal Production 18.1 Crop Production 40.5 House- Hold 5.0 Animal Production 21.0 Crop Production Unit: Million tonne (Mt) Air 14.3 Air 22.4 Air 24.1 Air Water 6.1 Water 11.7 Water 15.2 Water (Hou et al., 2013)

Total N losses to environment from 1980 to 2010 ～ 4 times

To atmosphere To water bodies Contribution of N losses from different systems

House- Hold 0.37 Animal Production 1.1 Crop Production 2.3 House- Hold 0.46 Animal Production 2.1 Crop Production 4.4 House- Hold 0.54 Animal Production 4.0 Crop Production 6.9 House- Hold 0.62 Animal Production 4.5 Crop Production Unit: Million tonne (Mt) Water 0.73 Water 1.98 Water 2.83 Water High P fluxes in the food chain of China

Total P losses to environment from 1980 to 2010 ～ 8 times

To water bodies Contribution of P losses from different systems

N and P losses of China in 2005 and EU in 2000 (kg N ha -1 ) China in 2005 EU in 2000 NH N2ON2O42 N2N NO x 152 N losses via leaching, runoff and erosion13716 P losses via leaching, runoff and erosion22* (Velthof et al., 2009; Ma et al., 2010) * No data

NUE and PUE in China China in 1980 China in 2005 Global NUEc3226~50 NUEa NUEf15914 PUEc PUEa1317~21 PUEf24719 Note: NUE= (O Main product / I Total )*100 (Smil, 2002; Howarth et al., 2003; Van der Hoek, 1998; Galloway, 2002; Liu et al., 2009; Schroder et al., 2010)

Three-Step Strategy to increase crop yield and nutrient use efficiency at the same time - For ensure both food security and environment quality simultaneously Crop productivity Water and nutrient input At present （ saving fertilizer ） The 2nd step Yield increase10%-20% （ High-yield ） The 3rd step Yield increase 30%-50% Increase soil fertility The 1st step Saving N by 30% without yield penalty

Cut down N fertilizer by 30-50% reduces N loss into environment greatly without diminishing crop yield! 2009 (First step)

Mean maize grain yield and modeled yield potential, N balance (fertilizer inputs-harvest outputs) and N applied per unit of grain produced for different management systems: integrated crop and soil system management approach (ISSM, n=66), farmers’ practice (FP, n=4548), and high-input, high-yielding studies (HY, n=43). (Chen et al., PNAS, 2011) ----Increase yield and NUE by 30-50% (Third step)

Three-Step Strategy to increase animal productivity and decrease nutrient losses at the same time

2 Three-Step Strategy in crop production 1 Optimize diets Environment Fertilizer industry Decrease pressure Decrease demand Decrease losses 3 Recycle wastes 2 Three-Step Strategy in animal production Nutrient management in food chain

N and P cost in the food chain in China (Ma et al., 2014)

Thanks for your attention ! Acknowledgments NSFC, MoA, MoE, MOST