The Chinese Academy of Agricultural Sciences (CAAS) and the International Food Policy Research Institute (IFPRI) jointly hosted the International Conference on Climate Change and Food Security (ICCCFS) November 6-8, 2011 in Beijing, China. This conference provided a forum for leading international scientists and young researchers to present their latest research findings, exchange their research ideas, and share their experiences in the field of climate change and food security. The event included technical sessions, poster sessions, and social events. The conference results and recommendations were presented at the global climate talks in Durban, South Africa during an official side event on December 1.

1. 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

2. 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

3. 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

4. N use in China & food security
N fertilizer
Grain yield

5. 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

6. 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

7. GHGs emissions from China’s
agriculture
Source CO2 Methane Nitrous Total
oxide
N fertilizer production & transport 235 26 13 274
(43 Mt)
P&K fertilizer production & transport 18 18
N fertilizer use for crops (32 Mt) 57 (170 rice*) 176* 233(403)
Other agricultural uses (3-5Mt) 15-25 15-25 30-50
Livestock – enteric & manure 295-443 172-258 467-701
Direct fossil energy inputs to agriculture 190 190
Total agricultural emissions 515-25 491-639 376-472 1382-1636
Total economy emissions 6,000 7,230
Agricultural emissions as % of total national emissions 19-22
* not closely N related *provisional estimate for indirect N2O
Source: SAIN, 2011

8. 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

9. Complexity of trade-offs between
food 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

10. 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

11. N overuse by province and crop
Province Crop Farmers Recommended % % yield
rate Rate* kg.N/ha overuse loss from
kg.N/ha 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

12. Overuse of N and poor root growth
N Overuse Optimum N
SAIN Policy Brief No 2

13. 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

14. Soil acidification greater with
vegetables and fruit than cereals
Soil 1980s 2000s 2000s
group/region
All crop systems Cereals Vegetables & fruit
pH value pH value pH value
Red & yellow soils 5.73 5.14 5.07
of South China
Paddy soils 6.33 6.20 5.98
North East 6.32 6.00 5.60
N China Plain & 7.96 7.69 7.38
Loess Plateau
Source: Guo et al., 2010

16. N related increase in eutrophication
and harmful algal blooms/red tides
1970s 1990s 2000 Mid 2000s 2008
5 51 55-61
Lake
eutrophication %*
5 45 68
Red tides/year**
* 25-50% from crop N
** up to 60% estuarine N from crop production

17. Overuse of N and > crop diseases:
Rice sheath blight
Source: Cu et al., 1996

18. 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

19. Costs of N overuse
Province Crop Farmers Recommended % overuse Cost of
rate Rate* kg.N/ha overuse
kg.N/ha 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

20. Impact of overuse & misuse of N
on farm incomes in Shaanxi
Income level Total household Cost of N % of household
（收入水平） income (yuan) overuse (yuan) income （占家庭
家庭总收入（元） 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
Source: Lu Yuelai, 2010

21. 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

22. 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

23. 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

24. INM is not just about limiting
N 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

25. INM and potential GHG savings
in Beijing/Hebei/Shandong
Farmers INM rate N saving % GHG
N rate from INM reduction
from INM
N input & GHG
benefit
kg synthetic N 588 286 302 51
fertilizer/ha/yr
Other benefits:
Reduced N loss by 56 23 33
leaching
Reduced N loss as 135 46 89
ammonia
Derived from Ju el., 2006

26. 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

27. 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

28. 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

29. 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

30. 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

31. 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

32. 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

33. Thanks to Project partners & funding bodies:
MoA, China; defra, FCO & dfid in UK
China
UK
•CAU (Zhang Fusuo, Zhang Weifeng,
Ju Xiaotang) •Rothamsted Research
•CAS Centre for Chinese Agricultural (David Powlson)
Policy (Huang Jikun, Jia Xiaoping •North Wyke Research
•4 case study Provinces: (Shaanxi – (David Chadwick)
NWAFU; Shandong; Jiangsu – CAS •University of East Anglia (Lu
Institute of Soil Science & Nanjing Yuelai)
Agricultural University; Jilin)