Increasing food security and minimising greenhouse gas emissions through improved

nitrogen management – lessons from the Chinese experience

David Norse

International Conference on Climate Change and Food Security, Beijing, November 6-8, 2011

Agriculture is part of the problem and part of the solution

Agricultural drivers for climate change are a threat to current food security as well as to long

term food security

Outline

• N fertilizer and the trade-off between food security and climate change

• Overuse and misuse of N as a threat to current food security

• Minimising greenhouse gas (GHG) emissions through improved nitrogen management (INM) and other policy measures

• Implications of the Chinese experience for other developing countries

N use in China & food security

N fertilizer

Grain yield

N production and use as drivers for climate change

• Agriculture is the main source of the powerful GHGs CH4 and N2O driving climate change globally & China

• Synthetic N fertilizer production & use and manure are the main source of N2O & livestock are now the main source of CH4

• Food demand exceeds the amount that can be produced from organic N inputs

Agricultures contribution to global GHG emissions

Global mean:

70% of agricultural GHG

emissions are connected

with N fertilizer  use: CO2 & N2O

Source: IPPC 4th Report

GHGs emissions from China’s agriculture

Source: SAIN, 2011

Source CO2 Methane Nitrous

oxide

Total

N fertilizer production & transport

(43 Mt)

235 26 13 274

P&K fertilizer production & transport 18 18N fertilizer use for crops (32 Mt) 57 (170 rice*) 176* 233(403)Other agricultural uses (3-5Mt) 15-25 15-25 30-50Livestock – enteric & manure 295-443 172-258 467-701Direct fossil energy inputs to agriculture 190 190Total agricultural emissions 515-25 491-639 376-472 1382-1636

Total economy emissions 6,000 7,230

Agricultural emissions as % of total national emissions

* not closely N related *provisional estimate for indirect N2O

19-22

Food demand, organic N inputs& unavoidable trade-offs

• Currently about 30 % of China’s N input comes from manure

• In the longer-term about 30% of synthetic N use could be replaced by N in manure & compost and biological N fixation but they also release GHGs

• Consequently food security will continue to be dependent on anthropogenic N inputs with some trade-offs between food security & climate change

Complexity of trade-offs betweenfood security and climate change

Much of the complexity stems from the way that overuse and misuse of N increases:

(a)GHG emissions & drives climate change, but

(b)Also causes or intensifies a range of other negative environmental impacts that increasingly threaten current food security

Current direct and indirect threats to food supply related to N use

• Yield loss• Restricted root growth• Soil acidification• Negative impacts on soil biology• Higher losses from pests & diseases• Increased lodging and greater harvesting losses• Greater eutrophication and increased frequency

and area of algal blooms

N overuse by province and crop

Province  Crop  Farmers rate

kg.N/ha 

Recommended Rate* kg.N/ha 

% overuse 

% yield loss from overuse

Jiangsu  rice  300  200  50  3

6 provinces  rice  195  133  47  >5

N China plain  wheat  325  128  150  4

N China plain  maize  263  158  66  5

Shaanxi  wheat  287  150‐225  >30  0

Shaanxi  maize  249 125 100  8

Shandong  tomato  Up to 630  150-300 >80 10  

Overuse of N and poor root growth

SAIN Policy Brief No 2

N Overuse Optimum N

Increase in top soil acidification:1980s -2000s

• Soil pH declined significantly in all major crop production areas & is projected to get worse

• It was caused primarily by high inputs of N fertilizer

• Acid deposition had only a small impact• Reduced productivity – toxic metals• Control is difficult and labour intensive

Source: Guo et al., 2010

Soil acidification greater with vegetables and fruit than cereals

Source: Guo et al., 2010

Soil group/region

1980s 2000s 2000s

All crop systems Cereals Vegetables & fruit

pH value pH value pH value

Red & yellow soils of South China

5.73 5.14 5.07

Paddy soils 6.33 6.20 5.98

North East 6.32 6.00 5.60

N China Plain & Loess Plateau

7.96 7.69 7.38

N related increase in eutrophicationand harmful algal blooms/red tides

1970s 1990s 2000 Mid 2000s 2008

Lake eutrophication %*

5 51 55-61

Red tides/year** 5 45 68

* 25-50% from crop N

** up to 60% estuarine N from crop production

Overuse of N and > crop diseases:Rice sheath blight

Source: Cu et al., 1996

Overuse and misuse of N as a threat to current food demand

Excess costs of production from overuse cause:•Reduced net farm income•Lower productivity growth & higher food price inflation which can limit the ability of the poor to buy all of their food needs

Costs of N overuse Province  Crop  Farmers 

rate kg.N/ha 

Recommended Rate* kg.N/ha 

% overuse  Cost of overuse RMB/ha

Jiangsu  rice  300  200  50  400

6 provinces  rice  195  133  47  250

N China plain  wheat  325  128  150  800

N China plain  maize  263  158  66  420

Shaanxi  wheat  287  150‐225  >30  250-550

Shaanxi  maize  249 125 100  500

Shandong  tomato  Up to 630  150-300 >80 1320-1920  

Impact of overuse & misuse of N on farm incomes in Shaanxi

Source: Lu Yuelai, 2010

Income level（收入水平）

Total household income (yuan)

家庭总收入（元）

Cost of N overuse (yuan)

% of household income （占家庭收入百分比）

1st Q 1664 153 9

2nd Q 6489 249 4

3rd Q 10442 225 2

4th Q 20260 221 1

Average 平均 9728 212 2

Agriculture as part of the solution: most of the cost-effective measures to minimise agricultural GHGs emissions involve improved N management in crop and livestock production

Minimising agricultural GHGs

• Integrated nutrition management• Increased water use efficiency• Increased soil carbon• Improved livestock waste management • Feed productivity• Subsidies, PES, & environmental taxes• Monitoring & evaluation

What is improved nitrogen management (INM)

• Use of application rates of synthetic N fertilizers that allow for the N already in the soil, in manure and in irrigation water & do not exceed the amount needed for optimum crop yields.

• Ensuring that N fertilizers are applied at the right time & best place.

• Choosing the correct mix of N, P & K and the best type of fertilizer to minimize GHG & ammonia emissions

INM is not just about limitingN overuse

It is also correcting:•Lack of micronutrients which can limit N availability•Bad water management e.g. excessive irrigation which leaches nitrate below root zone•Tillage & residue management practices that reduce carbon sequestration

All of these can increase direct & indirect N2O emissions – complex trade-offs

INM and potential GHG savings in Beijing/Hebei/Shandong

Derived from Ju el., 2006

Farmers N rate

INM rate N saving from INM

% GHG reduction from INM

N input & GHG benefitkg synthetic N fertilizer/ha/yr

588 286 302 51

Other benefits:

Reduced N loss by leaching

56 23 33

Reduced N loss as ammonia

135 46 89

Livestock waste management– mix of policy instruments

• Planning controls on location• Building regulations regarding drainage &

waste storage requirements• Limits on stocking rates & manure or slurry

disposal• Support for anaerobic digestion and

organic fertiliser production

Water use efficiency

Mix of regulatory and economic incentives:• controls on abstraction; • full economic cost water pricing; • subsidies or grants for installing drip-

irrigation & fertigation

Implications of the Chinese experience for other developing

countries

• Importance of limiting overuse of N• Improving INM• Importance of good communications

between farmers, extension workers, scientists & engineers

• Sharing technological progress• Importance of appropriate funding for

agricultural development

Limiting overuse of N

Underuse rather than overuse is the main problem in most developing countries but:•Overuse is common in parts of India where there is cereal intensive production•Hot spots occur elsewhere in Asia, Africa and Latin America eg. peri-urban intensive vegetable production•Hence China’s experience with INM is helpful

Adopting and adapting INM

• IRRI has promoted the sharing of INM experience among rice producing countries but there is scope for extending this to other cropping systems

• Chinese experience with estimating N budgets, GHG emissions & other environmental impacts can provide other countries with methods and default values to formulate their approach to INM

Sharing technological progress

• Chinese progress in the development of cost-effective slow-release formulations of N fertilisers and nitrification inhibitors

• Development of small scale machinery for tillage and fertiliser placement

• Global public goods - hybrid varieties and advances in biotechnology

Conclusions

• N essential for food production but it creates substantial GHGs and other negative environmental impacts that threaten food security

• These trade-offs are current as well as long-term and can be reduced but not eliminated

• INM is a cost-effective win-win-win approach to reducing both current and climate change related threats to food security but wider policy measures are needed

• Underuse of N is the problem in most developing countries but there are N hotspots needing INM

Thanks to Project partners & funding bodies: MoA, China; defra, FCO & dfid in UK

China

•CAU (Zhang Fusuo, Zhang Weifeng, Ju Xiaotang)•CAS Centre for Chinese Agricultural Policy (Huang Jikun, Jia Xiaoping•4 case study Provinces: (Shaanxi –NWAFU; Shandong; Jiangsu – CAS Institute of Soil Science & Nanjing Agricultural University; Jilin)

UK

•Rothamsted Research (David Powlson)•North Wyke Research (David Chadwick) •University of East Anglia (Lu Yuelai)