Comparison of the Impacts of Climate Change on Potential Productivity of Different Staple Crops in the Agro-Pastoral Ecotone of North China

The aim of this study is to compare the impacts of climate change on the potential productivity and potential productivity gaps of sunflower （Helianthus annuus）, potato （Solanurn tuberosurn）, and spring wheat （Triticumaestivurn Linn） in the agro-pastoral ecotone （APE） of North China. A crop growth dynamics statistical method was used to calculate the potential productivity affected by light, temperature, precipitation, and soil fertility. The growing season average temperature increased by 0.47, 0.48, and 0.52℃ per decade （p 〈 0.05） for sunflower, potato, and spring wheat, respectively, from 1981 to 2010. Meanwhile, the growing season solar radiation showed a decreasing trend （p 〈 0.05） and the growing season precipitation changed non-significantly across APE. The light-temperature potential productivity increased by 4.48% per decade for sunflower but decreased by 1.58% and 0.59% per decade for potato and spring wheat. The climate soil potential productivity reached only 31.20%, 27.79%, and 20.62% of the light-emperature potential produc- tivity for sunflower, potato, and spring wheat, respectively. The gaps between the light-temperature and climate-soil potential productivity increased by 6.41%, 0.97%, and 1.29% per decade for sunflower, potato, and spring wheat, respectively. The increasing suitability of the climate for sunflower suggested that the sown area of sunflower should be increased compared with potato and spring wheat in APE under future climate warming.

Impact of Climate Change on Maize Potential Productivity and the Potential Productivity Gap in Southwest China

The impact of climate change on maize potential productivity and the potential productivity gap in Southwest China（SWC） are investigated in this paper.We analyze the impact of climate change on the photosynthetic,light-temperature,and climatic potential productivity of maize and their gaps in SWC,by using a crop growth dynamics statistical method.During the maize growing season from 1961 to 2010,minimum temperature increased by 0.20℃ per decade（p 〈 0.01） across SWC.The largest increases in average and minimum temperatures were observed mostly in areas of Yunnan Province.Growing season average sunshine hours decreased by 0.2 h day^（-1） per decade（p 〈 0.01） and total precipitation showed an insignificant decreasing trend across SWC.Photosynthetic potential productivity decreased by 298 kg ha^（-1）per decade（p 〈 0.05）.Both light-temperature and climatic potential productivity decreased（p 〈 0.05） in the northeast of SWC,whereas they increased（p 〈 0.05） in the southwest of SWC.The gap between lighttemperature and climatic potential productivity varied from 12 to 2729 kg ha^（-1）,with the high value areas centered in northern and southwestern SWC.Climatic productivity of these areas reached only 10%-24%of the light-temperature potential productivity,suggesting that there is great potential to increase the maize potential yield by improving water management in these areas.In particular,the gap has become larger in the most recent 10 years.Sensitivity analysis shows that the climatic potential productivity of maize is most sensitive to changes in temperature in SWC.The findings of this study are helpful for quantification of irrigation water requirements so as to achieve maximum yield potentials in SWC.

CLIMATE CHANGE IN CHINA AND ITS INFLUENCE ON AGRICULTURE PRODUCTION IN THE LAST 40 YEARS

Using the meteorological data set for 1951—1990 over 160 stations,a series of 10-year running mean curves of temperature and precipitation averaged for the country and its 7 climate regions,as well as for each season,are obtained and analyzed.The six aspects of main results can be summarized about the climate change in China and its influence on agriculture production in the last 40 years.