Research On The Influence Of Meteorological Factors And Farmland Management Measures On Corn Yield In Chin

Climate warming has posed one of the greatest threats to global food security during the21 st century.While such a threat could be partially offset by promoting food production through human management.As an important component of grain crops in China,it is significant to focus on the key elements affecting changes in maize and to predict how yields will change in the future to ensure China’s food security.In this paper,based on the panel data of climatic,fertilization,and irrigation water available from the dataset of China’s 208 prefecture-level administrative divisions over the historical period(1982-2013),the optimal spatial panel model has been chosen to quantitatively disintegrated the relative effects of major climate factors and human activity factors on maize yield in China.The dominant factors affecting maize yields in the four maize planting regions were compared.Then,based on the climate model data and the combined scenarios of irrigation and fertilization set in this paper,the change of China’s maize yield under the future different scenario was simulated.The main conclusions are as follows:(1)From 1982 to 2013,the average maize yield in China’s four maize planting regions increased by 1.7 times.The growth rate of maize yield in the Southwest maize region and the South maize region both exceeded the national average.The average yield of these two maize planting regions was large,and the yield variation was relatively stable.For the climatic factors during maize growing period,the average temperature,killing degree days,and vapor pressure deficit all showed a significant upward trend.The trends of solar radiation and wind speed were declined,while the trends of diurnal temperature range and precipitation were not significant.Human activity factors were all on the rise.(2)Based on the optimal spatial model,i.e.,the spatial Durbin model(SDM)with a timefixed effect,it can be found that the overall impact of human activity factors(fertilizer use and irrigation)can offset the negative impact of climate change(e.g.,vapor pressure deficit(VPD),wind speed,killing degree days,and temperature)on maize yield in China’s maize planting regions.Maize yield would decrease by 15.2% per 0.1 k Pa increase in VPD.For every 1°C increase in average temperature,maize yield would decrease by 0.8%.For every 10°C increase in KDD,maize yield would decrease by 0.3%.However,adding 10 g of N&P fertilizer use per square meter would increase maize yield by 28.4%.(3)There are spatial differences in the determinants of maize yields: maize growth in the Northern spring maize region was mainly restricted by water resources,with higher VPD and temperature.The Huang-Huai spring-summer maize region was not only subject to the stress of climate factors,but also restricted by human activities.Human activities had little impact on maize yield in the Southwest maize region.Compared with other planting regions,the application of nitrogen and phosphorus fertilizers in the South maize region had a greater impact on increasing maize yield.(4)The deviation correction of the five CMIP6 model data was carried out based on the Equidistant Cumulative Distribution Function.The deviation between the annual mean of the revised multi-model ensemble of climate elements and the historical observation data decreased.And the spatial simulation capability of the revised multi-model ensemble of climate elements in China’s maize planting regions was improved(it was highly correlated with historical data,R ≈ 1).In addition to a few climate elements(i.e.,solar radiation,and VPD),multi-model ensemble simulations of the rest of the climate data were superior to individual models.(5)Based on the historical base period(1994-2013),the SDM was established to estimate the impact of climate change and human activities on China’s maize yield under different combination scenarios in the future.This study found that climate change will cause the average maize yield in China to change by 3.4±3.9%(SSP1-2.6),and 4.7±4.0%(SSP5-8.5)under 1.5℃global warming.While climate change will change the average maize yield in China by-1.7±5.0%(SSP1-2.6)and 0.9±4.4%(SSP5-8.5)under 2.0℃ global warming.Combined with four different future irrigation and fertilization combination scenarios based on historical data,it was found that although future climate change will have a large impact on maize yield,if the amount of fertilizer is slightly increased(the amount of fertilizer in the future is 5% more than that in2013)and the amount of irrigation is maintained(the amount of water used for irrigation in the future is maintained at 1.2 times or more than that in 2013),the future growth of China’s maize yield can still be guaranteed.