Zhao jin — the possible effect of climate warming on northern limits of cropping system and crop yield in china
The Possible Effect of Climate Warmingon Northern Limits of Cropping System and Crop Yield in China ZHAO Jin, YANG Xiaoguang China Agricultural University
Outline Background Scientific Questions ResultsPart 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
Background 0.74℃/100year 3.1mm/year 1.8mm/year The trend of annual mean air temperatureChanges in temperature, sea level and over the period 1951~2002 Northern Hemisphere snow cover IPCC,2007 China’s national assessment report on climate change, 2007
Background 3.5~6.5℃ 2.5~5.5℃ 3.5~6.5℃ 2.5~5.0℃Projected annual mean surface temperature for 2071~2100 under different scenarios China’s national assessment report on climate change, 2007
Multiple Cropping SystemClimatic change Crop growth and yields
Scientific Questions• 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?
Part I: The possible effects of climatic change on northern limits of cropping systems and crop yields in China
Weather data– 1950s to 2007. – 666 stations for better data recorded quality.
IndicesIndices for the countrywide cropping systems ≥0℃ accumulated extreme minimumCropping system date of 20℃termination temperature（℃·d） temperature(℃)One-cropping system ＜4000～4200 ＜-20 Early August～Early SeptemberTwo-cropping system ＞4000～4200 ＞-20 Early September～Beginning in late SeptemberThree-cropping system ＞5900～6100 ＞-20 Beginning in late September～Early November Liu X H and Han X L, 1985The 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)
Previous work One-cropping system Two-cropping system Three-cropping system The cropping systems in China (1950S-1980) Liu X H and Han X L, 1985
The change of northern limits of cropping systems One-cropping system Two-cropping system Three-cropping system （YANG Xiaoguang et al，2010）
The possible change of northern limits of two-cropping systemOne-cropping system Two-cropping system Compared with 1951 to 1980, the northern limits of the two-cropping system during 1981 to 2007 occurred significant 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 changed from almost zero to the region of SuiZhong, Anshan, Yingkou, Dalian.
The effects of northward of Two-cropping limits on the crop yields 54% ~ 106% Spring maize → winter wheat — summer maize Shaanxi: 82% 、Shanxi: 64% 、Hebei: 106% 、 Beijing:99%、Liaoning: 54%
The possible change of northern limits of three-cropping systemLargest spatial displacement in Hunan, Hubei, Anhui, Jiangsu, and Zhejiangprovince. Moved northwards about 103 km in Zhejiang province Moved northwards about 127 km in eastern and 29 km in western of Anhui province Moved northwards 30 km in Hubei province Two-cropping system Three-cropping system
The effects of northward of Three-cropping limits on the crop yields 27% ~ 58% winter wheat —middle rice → winter wheat—early rice—late rice Hunan: 52% 、Hubei: 27% 、Anhui: 58% 、Zhejiang: 45% （YANG Xiaoguang et al，2010）
The possible change of northern limits of grade 1 area of cropping system South ChinaⅥ：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. （ ZHAO Jin et al，2010）
The effects of change of grade 1 area on the crop yields Ⅵ-Ⅷ Ⅷ-Ⅹ Ⅶ-Ⅹ Province Wheat/maize- Wheat/rice Wheat/maize- Wheat/rice- Wheat/maize- wheat/rice -wheat/rice/rice wheat/rice/rice wheat/rice/rice 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 intowinter wheat- middle season rice （ ZHAO Jin et al，2010）
The change of northern limits of grade 1 area of cropping system North ChinaⅡ 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 （ LI Kenan et al，2010）
The effects of change of grade 1 area on the crop potential yield Potential yield ( kg·hm-2)Changes of the first Station Period Winter wheat + division Spring wheat Spring maize Winter wheat summer maize 1951-1980 — 12834 — — Dalian in 1981—2007 — — 6375+9278 — LiaoningThe sensitive region increase* 2820 of cropping system betweenⅣ and Ⅵ 1951—1980 — 13073 — — Suizhong in 1981—2007 — — 5542+9228 — Liaoning increase 1697 1951—1980 — — — 3716 Yangquan in 1981—2007 — — 4289+8430 — ShanxiThe sensitive region Increase 9002 of cropping system between Ⅲ and Ⅵ 1951—1980 6482 — — — Zunhua in 1981—2007 — — 4502+8064 — Hebei Increase 6821 1951—1980 5743 — — — Sunwu in 1981—2007 — 7189 — — HeilongjiangThe sensitive region Increase 1446 of cropping system between Ⅲ and Ⅳ 1951—1980 5550 — — — Keshan in 1981—2007 — 9512 — — Heilongjiang increase 3962
The change of northern limits of winter wheat Moved northwards The east of Liaoning: 120km， The west of it : 80km Hebei: 50km Shanxi: 40km The west of Shaanxi: 47km Inner Mongolia、Ningxia: 200km Moved westwards Gansu: 20km Qinghai: 120km The change of northern limits of winter wheat in China
The change of wheat yield due to the cropping system changed 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 northern limits of double riceThe north limits moved northwards Zhejiang: 47km Anhui: 34km Hubei、Hunan: 60kmYield increasing rate(wheat-middle rice→green manure-early rice-late rice) Zhejiang: 13.8%、Anhui: 12.2% Hubei: 1.8%、Hunan: 29.9%
Part II The possible impact of climatic change on the northern limits of spring maize and its agro- meteorological disaster in Northeast China.
The effect of climatic change on maize in Northeast China Study region
IndicesHeat requirements for different maturity-style maize maturity-style maize Early-maturity Middle-maturity late-maturity ≥10℃ degree day (℃·d) 2100-2300 2300-2700 ＞2700Indices of delayed chilling injury for spring maize The cumulative average temperature from May to 80.0 85.0 90.0 95.0 100.0 105.0 September（℃） △T5-9 -1.7 -2.4 -3.1 -3.7 -4.1 -4.4 (China Meteorological Administration, 2009)
The change of planting structure of different maturity-type maize 1961-1970 1971-1980 1981-1990 Unsuitable area Early-maturity Middle-maturity Late-maturity 1991-2000 2001-2007 （ LIU Zhijuan et al，2010）
The change of water deficient ratio of maize Maturity-type Fuyu Qiqihaer Anda Haerbin Kaiyuan Dandong 1961-1970 Middle-maturity1960 S 21% 1971-1980 24% 31% 8% 1981-1990 -8% -59%2000 S Late-maturity 28% 35% 25% 18% -8% -53% 1991-2000 2001-2007 The slope of water deficient ratio
The change of Severe chilling injury 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 The change of the maximum frequency severe chilling injury of maize in the cropping system change area Maturity-type 1960s In the early of 21 century Late-maturity 12% 21%Middle-maturity 18% 27% （Zhao Junfang，et al. 2009） CAU China Agricultural University
Conclusions• 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 chang ing area.• The ago-meteorological disaster should be considered on the changes in cropping systems.
AcknowledgementsMinistry of Science and Technology of China (‘973’ project) Ministry of Agriculture of ChinaProf. Chen FuProf. Liu XunhaoProf. Han XianglingStudents： Liu Zhijuan, Li Kenan, Cheng Difang, Wang Wenfeng, Li Yong, Xu Huajun, Ye Qing.