The Possible Effect of Climate Warming on Northern Limits of Cropping System

and Crop Yield in China

ZHAO Jin, YANG Xiaoguang

China Agricultural University

Background

Scientific Questions

Results

Part I: The possible effects of climatic change on northern

limits of cropping systems and crop yields in China.

Part II: The possible impact of climatic change on the northern

limits of spring maize and its agro-meteorological

disaster in Northeast China.

Conclusions

Outline

Changes in temperature, sea level and Northern Hemisphere snow cover

0.74℃/100year

1.8mm/year

3.1mm/year

IPCC,2007

The trend of annual mean air temperature over the period 1951~2002

China’s national assessment report on climate change, 2007

Background

Projected annual mean surface temperature for 2071~2100 under different scenarios

China’s national assessment report on climate change, 2007

3.5~6.5℃ 2.5~5.5℃

3.5~6.5℃ 2.5~5.0℃

Background

Climatic changeMultiple Cropping System

Crop growth and yields

• The possible effects of climatic warming on northern limits of cropping systems?

• How the change of cropping systems affects crop yields in China ?

• The vulnerability of agro-meteorological disasters after the north limits of cropping system changed?

Scientific Questions

The possible effects of climatic change on

northern limits of cropping systems and crop

yields in China

Part I:

– 1950s to 2007. 

– 666 stations for better data recorded quality. 

Weather data

Indices for the countrywide cropping systems

Cropping system ≥0℃ accumulated temperature（℃·d）

extreme minimum temperature(℃) date of 20℃termination

One-cropping system ＜4000～4200 ＜-20 Early August～Early September

Two-cropping system ＞4000～4200 ＞-20 Early September～Beginning in late September

Three-cropping system ＞5900～6100 ＞-20 Beginning in late September～Early November

Liu X H and Han X L, 1985

The northern limits of winter wheat

mean minimum temperature of December: -15℃extreme minimum temperature: -22~-24℃

(Cui D C，1991)

The northern limits of double rice≥10℃ accumulated temperature: 5300℃·d

(National Agricultural Zoning Commission , 1991)

Indices

Liu X H and Han X L, 1985

The cropping systems in China (1950S-1980)

One-cropping system

Two-cropping system

Three-cropping system

Previous work

One-cropping system

Two-cropping system

Three-cropping system

The change of northern limits of cropping systems

（YANG Xiaoguang et al，2010）

One-cropping system

Two-cropping system

Compared with 1951 to 1980, the northern limits of thetwo-cropping system during 1981 to 2007 occurredsignificant spatial displacement in Shaanxi, Shanxi,Hebei, Beijing and Liaoning provinces.

the boundary moved northwards about 26 km in Shanxi,Shaanxi and Hebei province

in Liaoning province, the area of two-cropping system changedfrom almost zero to the region of SuiZhong, Anshan, Yingkou, Dalian.

The possible change of northern limits of two-cropping system

Spring maize → winter wheat — summer maizeShaanxi: 82% 、Shanxi: 64% 、Hebei: 106% 、

Beijing:99%、Liaoning: 54%

54% ~ 106%

The effects of northward of Two-cropping limits on the crop yields

Two-cropping system

Three-cropping system

Largest spatial displacement in Hunan, Hubei, Anhui, Jiangsu, and Zhejiang province.

Moved northwards about 103 km in Zhejiang provinceMoved northwards about 127 km in eastern and 29 km in western of Anhui province Moved northwards 30 km in Hubei province

The possible change of northern limits of three-cropping system

winter wheat —middle rice → winter wheat—early rice—late riceHunan: 52% 、Hubei: 27% 、Anhui: 58% 、Zhejiang: 45%

27% ~ 58%

The effects of northward of Three-cropping limits on the crop yields

（YANG Xiaoguang et al，2010）

（ ZHAO Jin et al，2010）

The possible change of northern limits of grade 1 area of cropping system

South China

Ⅵ：Area of two-crops in irrigated land and two/one-crop in dry land in Huanghuaihai area;Ⅶ：Area of two-crops in paddy fieldand two/one-crop in dry land in Southwest plateau or mountain; Ⅷ：Area of wheat-rice in Jianghuai plain or hilly;Ⅸ：Area of two/three-crops in paddy/dry land in Sichuan basin; Ⅹ：Area of two/three-crops in paddy field in middle-lower Yangtze plain or hilly; Ⅺ：Area of later two/three-crops and thermal.

Province

Ⅵ-Ⅷ Ⅷ-Ⅹ Ⅶ-Ⅹ

Wheat/maize-wheat/rice

Wheat/rice-wheat/rice/rice

Wheat/maize-wheat/rice/rice

Wheat/rice-wheat/rice/rice

Wheat/maize-wheat/rice/rice

Hunan 53% 105%

Hubei 26% 86%

Anhui 22% 36% 67%

Jiangsu 29% 35% 74%

Zhejiang 44% 100%

Shanghai 58% 76%

Ⅵ-Ⅷ : the region by area Ⅵ into area in Ⅷ corresponding provinces;Wheat/maize: the cropping pattern of winter wheat-summer maize; Wheat/rice : the cropping pattern of winter wheat- middle season riceWheat/rice/rice : the cropping pattern of winter wheat-early season rice-late riceWheat/maize-Wheat/rice: the cropping pattern of winter wheat-summer maize change into winter wheat- middle season rice

The effects of change of grade 1 area on the crop yields

（ ZHAO Jin et al，2010）

（ LI Kenan et al，2010）

The change of northern limits of grade 1 area of cropping system

North China

Ⅱ Area of one-crop for cool-warm plants in semi-arid medium plateau in northernⅢ Area of one-crop for warm-cool plants in semi-arid low plateau in northeast and northwestⅣ Area of one-crop for warm-cool plants in semi-humid plain or hilly in northeastⅤ Area of one-crop for irrigating warm-cool plants in day land in northwestⅥ Area of two-crops in irrigated land and two/one-crop in dry landin Huanghuaihai areaⅧ Area of wheat-rice in Jianghuai plain or hilly

Changes of the first division

Station Period

Potential yield ( kg·hm-2)

Spring wheat Spring maizeWinter wheat + summer maize

Winter wheat

The sensitive region of cropping system betweenⅣ and Ⅵ

Dalian in Liaoning

1951-1980 — 12834 — —

1981—2007 — — 6375+9278 —

increase* 2820

Suizhong in Liaoning

1951—1980 — 13073 — —

1981—2007 — — 5542+9228 —

increase 1697

The sensitive region of cropping system between Ⅲ and Ⅵ

Yangquan in Shanxi

1951—1980 — — — 3716

1981—2007 — — 4289+8430 —

Increase 9002

Zunhua in Hebei

1951—1980 6482 — — —

1981—2007 — — 4502+8064 —

Increase 6821

The sensitive region of cropping system between Ⅲ and Ⅳ

Sunwu in Heilongjiang

1951—1980 5743 — — —

1981—2007 — 7189 — —

Increase 1446

Keshan in Heilongjiang

1951—1980 5550 — — —

1981—2007 — 9512 — —

increase 3962

The effects of change of grade 1 area on the crop potential yield

The change of northern limits of winter wheat in China

Moved northwardsThe east of Liaoning: 120km，

The west of it : 80kmHebei: 50kmShanxi: 40kmThe west of Shaanxi: 47kmInner Mongolia、Ningxia: 200km

Moved westwardsGansu: 20kmQinghai: 120km

The change of northern limits of winter wheat

the yield of winter wheat and spring wheat in Hebei province

Data sources:《China Statistical Yearbook》

Northern limits of winter wheat moved north，leading to about 25%grain yield increase in the changing area if the cropping system changed from spring wheat to winter wheat.

The change of wheat yield due to the cropping system changed

The north limits moved northwards

Zhejiang: 47km

Anhui: 34km

Hubei、Hunan: 60km

Yield increasing rate (wheat-middle rice→green manure-early rice-late rice)

Zhejiang: 13.8%、Anhui: 12.2%

Hubei: 1.8%、Hunan: 29.9%

The change of northern limits of double rice

The possible impact of climatic change on the

northern limits of spring maize and its agro-

meteorological disaster in Northeast China.

Part II

Study region

The effect of climatic change on maize in Northeast China

Heat requirements for different maturity-style maize

maturity-style maize Early-maturity Middle-maturity late-maturity

≥10℃ degree day (℃·d) 2100-2300 2300-2700 ＞2700

The cumulative average

temperature from May to

September（℃）

80.0 85.0 90.0 95.0 100.0 105.0

△T5-9 -1.7 -2.4 -3.1 -3.7 -4.1 -4.4

Indices of delayed chilling injury for spring maize

(China Meteorological Administration, 2009)

Indices

1961-1970 1971-1980 1981-1990

1991-2000 2001-2007

Unsuitable areaEarly-maturityMiddle-maturityLate-maturity

（ LIU Zhijuan et al，2010）

The change of planting structure of different maturity-type maize

1961-1970 1981-1990

1991-2000 2001-2007 The slope of water deficient ratio

1971-1980

Maturity-type Fuyu Qiqihaer Anda Haerbin Kaiyuan Dandong

1960 S Middle-maturity 21% 24% 31% 8% -8% -59%

2000 S Late-maturity 28% 35% 25% 18% -8% -53%

The change of water deficient ratio of maize

1960s 1970s 1980s

1990s the early of 21 century 1961-2007 average

（Zhao Junfang，et al. 2009）

The change of Severe chilling injury of maize

Maturity-type 1 9 6 0 s In the early of 21 century

Late-maturity 12% 21%

Middle-maturity 18% 27%

CAUChina Agricultural University

The change of the maximum frequency severe chilling injury of maize

in the cropping system change area

（Zhao Junfang，et al. 2009）

The change of Severe chilling injury of maize

• The climate changes caused the northwards movement of north limits of cropping system, winter wheat and double rice.

• The changes will increase the unit grain yield in the changing area.

• The ago-meteorological disaster should be considered on the changes in cropping systems.

Conclusions

Ministry of Science and Technology of China(‘973’ project) 

Ministry of Agriculture of China

Prof.  Chen FuProf.  Liu XunhaoProf.  Han Xiangling

Students：Liu Zhijuan, Li Kenan, Cheng Difang, Wang Wenfeng, Li Yong, Xu Huajun, Ye Qing. 

Acknowledgements

Thank you for your attention！