Effects Of Climate Change On Rice Production And Its Adaptation In Double Rice Cropping System Of China

The fact of climate change has resulted in the increase on temperature and the aggravation of extreme weather events.Such changes have threatened crop production and food security,thus,understanding climate change and its mechanisms on crop production would help to adjust management practices for maintaining the sustainability and increasing crop productivity.Double rice cropping plays a key role in rice production and food security in China,however,double rice production in China has faced with various challenges recently.A scientific frame work on the effects of climate change,the projections of yield change under future scenarios,and the adaptations on climate change by farmers is of great importance for the adaptation of climate change and the maintenance of double rice production.This study systematically analyzed the spatial and temporal changes on climate variables,described the yield trajectory of double rice,identified climate change and extreme weather on the rice yield and its variation,projected double rice yield under various future scenarios,investigated farmers' adoption of adaptation measures.The main results were as following:(1)Double rice in Southern China experienced an increase of temperature during past decades.The mean temperature(Tavg)increased significantly at 78.52%and 75.1%of the stations examined for the early and late rice during its growing season,respectively.However,high inter-annual variation in precipitation(Rain)and radiation(Srad)decreased were also detected.Temperature increase and solar radiation decrease trend will aggravate under most of the future scenarios,with the mean temperature during the early rice season will increase by-2.45?,while solar radiation during late rice season will decrease by 3.24 MJ/m2/day.Double rice mainly experienced with the extreme temperature during reproductive stage,the frequency and intensity of high temperature was identified for early rice,specifically in the middle and lower reaches of the Yangtze river,while the extreme low temperature was alleviated for late rice.Precipitation was highly spatial distributed and most of the effective precipitation was in the vegetative stage,while less effective precipitation in the reproductive stage.(2)Yield stability of double rice was threatened due to climate change in Southern China.Yield varied nonlinearly in most provinces and fluctuated more for late-rice.Double rice production exhibited stagnation in 1980-2012.The joint effects of the climate change during past decades increased yields of early and late rice by 0.51%and 2.83%,respectively.Climatic variation accounted for 40.04%and 29.72%of yield variability for early-and late-rice,respectively.While a case-study in Hunan province showed that vapor pressure deficits changed yields by-6.66%for the early rice and-1.82%for the late rice.(3)A case study of typical sites,Hunan province,indicated that the effects of climate change on the yield of early and late rice in the region were different.Through the analysis.climate change will lead to yield reduction by 7.81%and 9.40%for early rice during 2031-2060 and 2061-2090,respectively.However,the future climate change is beneficial to yield increase for late rice(by 4.54%),but with a declining trend.(4)The cropping pattern,local farmers' attitude on climate change,and the adoption of management practices was analyzed on the basis of the questionnaire from representative counties.Double rice in Hunan province was facing the many challenges.Among these challenges,labors aging issues,tight crop duration,production cost,labor input,and climate change were the major factors that influenced planting desire of farmers.Results also indicated that most farmer widely believed that the production of double cropping rice was at risk,but they did not have a clear perception of the impact of climate change on the production of double-cropping rice.The cognition of farmers' historical climate change restricted the adoption of adaptation measures,and thus further influencing the farming adaptation for the future double cropping rice production.