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. Soil Organic Carbon
Sequestration
and Crop Production
Minggang XU
Wenju Zhang, Yilai Lou, Hui Li
(Institute of Agricultural Resources and
Regional Planning, CAAS, China)

2. Contribution from
Basic Soil Fertility
Soil
productivity
Effects of Management:
Fertilization,
irrigation, …...

3. Crop Productivity:
Soil fertility interaction with efficiency of Water
and fertilizers
Increasing efficiency of
water and fertilizers
Crop
水
肥
效
yield
应
Increasing Soil fertility
地
力 基础地力
效
应

4. Soil Fertility Contribution to Grain Yield in China: 52%
For rice, wheat and maize in average
单季稻 早稻 晚稻
<20
小麦 玉米 20~30
30~40
40~50
50~60
60~70
70~80
80~90
>90
Tang and Huang, 2009

5. Soil Fertility Contribution to Grain Yield in China: 52%
Lower 20% than that of USA
单季稻 早稻
Why??? 晚稻
Yield
W‐F Soil Fertility
W‐ F
<20
小麦 玉米 20~30
Fertility 30~40
40~50
Soil
China
50~60
USA
60~70
70~80
Same Varity 80~90
>90
Tang and Huang, 2009

6. Lower Soil Fertility in China
Low SOM
In China, SOM in 26% of arable soil is less than 1% ,
which is only 30-50% of European Soils.
Requirement:
Techniques to increase soil fertility, SOC
Cinnamon
Region Brown earths Chernozems
soils
China 1％－1.5％ ≈1% ≈3%
Europe >3% >2% ≈8%

7. Outline
SOC, soil fertility, and crop production
Long-term experiments in cropland of China

8. Part One
SOC, soil fertility and crop
production

9. Soil fertility, SOC pool, and food security
Climate
change
food
security
SOC Crop
production
Environment
Soil fertility -friendly

10. Three questions
Relationship soil fertility, Soil Organic Carbon
(SOC) and crop production
Critical SOC for high crop production
Principle and technology for increasing SOC

11. Question Ⅰ
Relationship of SOC, soil fertility
and crop production

12. What is soil fertility?
Soil fertility-
An important characteristic of soil
quality
The ability to supply the essential
nutrients and water for plant growth

13. SOM or SOC is the basis and core of
the soil fertility!
The improvement of SOC and soil
fertility is fundamental of ensuring
food security!
SOC pool － Soil fertility －
Soil productivity

14. SOM increase with crop yield for four
soil types in China
河南潮土
SOM
SOM
Fluvo-aquic soil Lime concretion black soil
SOM
SOM
Gray fluvo-aquic soil Whitish soil

15. SOC, crop yield and yield sustainability in
cropland of China
Wuchang Nanchang Jinxian
wheat rice corn
Yield
Suining rice Wuchang rice
Nanchang rice Jinxian corn
SOC
SOC increase by 10%， Suining
Wuchang
Wuchang wheat：74%
Nanchang
Nanchang rice: 42% Jinxian
Jinxian corn：110%
SOC

16. Statistical results
There is a close correlation between the average grain yield in
normal years and SOC content in cropland in the major grain-
producing areas
In upland area in north China, the SOC content of 1 g/kg is
equivalent to the grain productivity of 0.3 -0.5t/ha
In paddy area in south China, the SOC content of 1 g/kg is
equivalent to the grain productivity of 0.4-0.6 t/ha.
On average, with the increase of 1 g/kg of SOC content, the
increase of grain yield stability ranges from 10% to 20%.

17. SOC trend under different fertilization in Paddy field
25
25 CK NPK NPKS Jiangxi
23 20
21 15
19 10
CK NPK
SOC g/kg
17 5 50F+50M 30F+70M
Hunan 70F+30M
15
（
0
1980 1985 1990 1995 2000 2005 1980 1985 1990 1995 2000 2005
20 22 CK NPK
CK NPK
21 NPKM NPK‵M
NPK+M1 1.5(NPK)+M1
）
18 20
19
16
18
14 17
16
12
Sichuan
15
Zhejiang
10 14
1990 1995 2000 2005 1990 1992 1994 1996 1998 2000 2002
Year (a)

18. Change trend: Yield VS. SOC
(1) Non-fertilization
SOC change rate
Region Land use Crop yield change
t/ha/yr
Northeast upland decreased -0.11 to-0.27
Northwest upland decreased -0.17 to -0.42
Huanghuaihai upland decreased -0.10 to 0.10
South China upland decreased maintained
75% of sites
paddies maintained -0.28 to 0.26

19. (2) Chemical fertilization
Yield increased SOC changed
Region Land use
(%) (t ha-1 yr-1)
Wheat:48
Northeast upland maintained
Corn:58
Wheat:95
Northwest upland -0.19 to -0.23
Corn:72
Wheat:168
Huanghuaihai upland 0.07 to 0.4
Corn:78
Wheat: 120
South China upland 0.05 to 0.13
Corn:491
paddies Rice:54 0.03 to 0.16

20. (3) With manure and straw
Yield increased SOC changed
Region Land use
(%) (t ha-1 yr-1)
Wheat:66
Northeast upland 0.77-1.03
Corn:77
Wheat:268
Northwest upland 0.09-1.29
Corn:109
Wheat:309
Huanghuaihai upland 0.4-0.7
Corn:141
Wheat:278
South China upland 0.6-1.0
Corn:1326
paddies Rice:75 0.15-0.88

21. Major conclusions from the long-term
experiments：
SOC content can be significantly accumulated
under the long-term manure application alone
or combined with fertilizer；
The increase in SOC content can improve soil
fertility and thus enhance crop yield;
Manure application is an useful option for
increasing soil fertility, ensuring food security
and promoting agricultural sustainability.

22. Question Ⅱ
Critical SOC level for high crop
production
(A case study in Black soil)

23. Long-term experiment site
The selected long-term field experiment：
located in Gongzhuling city, Jilin province,
started in 1980
Cropping system：rainfed continuous corn
Soil type：black soil

24. Experimental design
Split-plot design: three main-treatments (manure)
and eight sub-treatments (fertilizers)
Main- Sub-treatment (Chemical fertilizer)
treatment
(Manure)
M0 CK N P K NP NK PK NPK
M2 CK N P K NP NK PK NPK
M4 CK N P K NP NK PK NPK
Application rate
Manure Chemical fertilizer
M0 –0 m3/ha (no manure) Pure N -- 150 kg/ha
M2 --30 m3/ha P2O5 -- 75 kg/ha
M4 --60 m3/ha K2O -- 75 kg/ha

25. After 29 years in 2009,
Still big differences
for chemical
fertilizers in Mo Plot

26. After 29 years in 2009,
However, no When and
significant
differences for Why?
chemical fertilizers
in M2 and M4 Plots

27. Dynamic of yield increment due to fertilizer
under different manure rates
M0 M2
M4

28. SOC dynamic under different manure rates

29. Relationship between yield increment due to
fertilizer and SOC
SOC=17.6g/kg
y1 = -30.14x + 543.64
R2 = 0.3745** SOM=30.3g/kg
y2 = -1.6295x + 43.034
R2 = 0.1596**

30. Major Conclusions for this part
1) When the SOM content reached to 30 g/kg，the chemical
fertilizer can be completely replaced with the manure for
achieving the expected high yield!
2) The results obtained from 160-yr Roth experimental
station show that proper chemical fertilizer application
can maintain high yield. However, our results indicate
that manure alone can also produce the equivalent high
yield when the soil fertility is high enough.
3) This is very important for Organic Agriculture or
Organic Framing and agricultural sustainable
development!

31. Question Ⅲ
Principle and quantitative
technology for increasing SOC

32. SOC change is determined by the
balance of the C input and output
SOC usually shows a linear increase with
C input when the SOC has no saturation
limitation

33. SOC trend under different fertilization in Upland
Jiangsu
SOC g/kg
（ Xinjiang
25 CK NPK
）
NPKM 1.5NPKM
20 M
15
Henan
10
5
Hunan
0
1990 1995 2000 2005
Year (a)

34. Regression between SOC changed and
C input in upland of China
SOC changed
SOC0=9.49
SOC0=15.43 SOC0=13.05 SOC0=11.54
（ SOC0=6.5 SOC0=6.67 SOC0=8.58
t/ha/yr
）
C input （t/ha/yr）

35. SOC Response to C Input
Conversion
coefficient of
C input
SOC Changed
（
C input to
t/ha/yr
maintain SOC
）
C input （t/ha/yr）

36. The relations are used to guide
the application of manure and
straw to improve soil fertility for
sustainable agriculture

37. C input to maintain SOC
Manure/ straw needed to
C input to maintaining SOC
Initial SOC maintain (t/ha/yr)
Site
(g/kg) SOC
( t C/ha/yr) Fresh pig Rice
manure straw
祁阳QY 8.6 0.8 18 2.3
遂宁SN 9.2 0.8 16 2.0
武昌WC 15.9 2.2 23 5.4
南昌NC 14.9 2.5 26 5.8
望城WC 19.7 1.4 29 3.6

38. C input to increase SOC by 10%
C input to Manure/ straw needed to
Initial Target increase increasing SOC by 10%
Site SOC SOC SOC (t/ha/yr)
(g/kg) (g/kg) by 10%
Fresh pig
( t C/ha/yr) Rice straw
manure
祁阳QY 8.6 9.4 1.89 33.5 4.2
遂宁SN 9.2 10.1 1.49 36 3.3
武昌WC 15.9 17.5 3.69 46 8.2
南昌NC 14.9 16.7 3.33 48 7.4
望城WC 19.7 21.7 4.05 60 9

39. Part Two
Long-Term Experiments (LTEs)
in Cropland of China

40. Importance of LTEs
Long-term experiment: an important
research means of soil science
Revealing the change in soil quality,
guiding rational fertilization, and
protecting ecological environment and
agricultural sustainable development

41. LTEs In the World
Longer than 100 years: around 20 sites
The Longest One:
Rothamsted, established in 1843,
168-year history

42. The classical experiments at Rothamsted
N, P, K,
Manure Broadbalk
Continuous
Wheat
Experiment
First sown 1843

43. LTEs In the World
The 2nd Longest One: Morrow
Plots, located in University of
Illinois at Chamigan-Urbana,
established in 1876
135-year history, Foundation of
USA Agri.

44. Effects of Rotation and Fertilization on Crop Productivity
and Soil Quality, National Historical Landmark
2011年11月11日

45. LTEs In China
1.Chemical fertilizer experiment net: began
during “the 6th five-year plan” and conducted
about in 1980
2.The Chinese National Soil and Fertilizer Long-
Term Monitoring Net: set up during “the 7th five-
year plan” and conducted in 1990

46. National long-term fertilizer experiment net
From 1980, about 80 long-term fertilizer experiments through 22
provinces and 10 soil types in China, conducted to investigate the
effect, rate and ratio of N, P and K fertilizers
全国定位试验点分布示意图
▲
▲
▲ ▲
▲
▲ ▲
▲ ▲▲▲
▲
▲ ▲
▲▲
▲
图例 ▲
▲
▲ ▲ ▲ ▲▲ ▲
■ 双季稻区试验点； ▲
▲ ▲ ■
■
■ 水旱两熟区试验点； ■ ■
■
■ ■ ■ ■■ ■
■ ■ ■ ■
▲ 旱作两熟区实验点 ■
■
■ ■
▲ 旱作一熟区试验点 ▲ ■
■
■
■ ■
■ ■
■ ■
■
■ ■

47. ● CSFEN was established in 1990
● There are 9 experimental sites
in the network all over China
Black soil
Gray dessert soil
Drab fluvo-aquic soil
Fluvo-aquic soil
Paddy soil
Loess soil
Purple soil
Red soil
China Long-term
Soil Fertility Experiment
Paddy soil
Network (CSFEN)

48. Ongoing LTEs in China started in 1980s
60 sites, including
10 soil classification；
10 rotation systems
90

49. Collected data from long-term experiments in China
(more than 20 yrs)

50. Published a Book:
Evolvement of
soil fertility in
China
Cooperated by 50
researchers

51. Major Publications-SCI Papers
Soil organic carbon dynamics under long-term fertilizations in arable land of
northern China. Biogeosciences， 2010, 7: 409-425 （IF 3.5）
Soil organic carbon, total nitrogen and grain yields under long-term fertilizations
in the upland red soil of southern China. Nutr. Cycl. Agroecosyst 2009.
84:59-69 (IF 1.8）
Long-term effects of manure application on grain yield under different cropping
systems and ecological conditions in China. The Journal of Agricultural
Science . 2009, 147, 31-42. （IF 1.3）
Trends in grain yield and soil organic carbon in a long-term fertilization
experiment in the China Loess Plateau. J. Plant Nutr. Soil Sci. 2008,171:448-457.
（IF 1.6）
Crop Yield and Soil Responses to Long-Term Fertilization on a Red Soil in
Southern China. Pedosphere. 2009, 19 (2): 199 – 207. （IF 0.81）

52. Thanks for attention!
Welcome you to visit
China Long-term
Experiments
Do Collaborations!