Comparative Study Of Winter And Spring Wheat’s Yield And Meteorological Disaster Characteristics In Ningxia Under The Background Of Climate Change

Ningxia is located in the sensitive cropping areas where the cropping northern limit of winter wheat shifted northward and expanded westward. Climate warming and temperature rising in winter will have directly impacts on the wheat production in Ningxia. Thus it was important and useful to analyze the temporal and spatial distribution of agricultural climate resources during the growing season of spring wheat and winter wheat, analyzing the change of crop potential production and occurring rule of meteorological disaster for the adaption of climate change. In this study, the meteorological data of Ningxia from1961to2010and the phenology data of wheat and crop yield data of wheat were collected. The methods we used inculded the agro-climatic index, index of meteorological disaster the ’correction step by step’ method, the high-stability coefficient, and grey relational analysis. Combined the mathematical statistics mehods with the spatial interpolation method, the temporal and spatial distribution and utilization characteristic of agricultural climate resources during the growing season of winter wheat and spring wheat in Ningxia were analyzed. The change of possible planting area for winter wheat and the suitable cultivation zones of wheat were also cleared. Besides, the occurring rule of meteorological disaster during the growing season of winter wheat and spring wheat in Ningxia were compared. The main conclusions are as follows:(1) The sunshine hours of the growth season of winter wheat and spring wheat increased in most areas. The active accumulated temperature above0℃increased obviously in Ningxia, especially in the Yellow River Irrigation District, while the increase trend in the Southern Mountain Area was relative smaller. The decrease trends of the absolute value of accumulated negative temperature during the wintering period were observed in the whole region, especially in Yinchuan, Tongxin and Guyuan, where the decrease trends passed the test of significance. There was no obvious decrease for the precipitation of each growing season in the Yellow River Irrigation District and the Central Arid Zone, while the decrease trend was significant in the Southern Mountain Area. The trends of the reference crop evapotranspiration in the study area showed increased, and significant both in the Yellow River Irrigation District and the Southern Mountain Area.(2) Under the background of climate warming, the possible of planting area for winter wheat increased, which accounted for16%,18%,75%,86%and74%of the total research area for each decade during1961to2010, respectively. The photo-thermal potential productivity of spring wheat decreased from north to south, where the high value region located in the Yellow River Irrigation District, and the low value region was Southern Mountain Area. Whereas, the climate potential productivity decreased from north to south. The increased trends for the photo-thermal potential productivity and climate potential productivity for both winter wheat and spring wheat were significant during1961to2010, and meanwhile the trend for winter wheat larger than spring wheat’s. Without considered the influence of agro-meteorology disaster, the suitalbe region for winer wheat planting was Yellow River Irrigation District as the condition was irrigated, thus was the Southern Mountain Area as the condition was unirrigated. The same as spring wheat. Due to the better irrigation condition and higher suitable value for winter wheat, the Yellow River Irrigation District was more suitable for winter wheat than spring wheat. Meanwhile, due to the limited of irrigation condition and higher suitable value for spring wheat, the Southern Mountain Area and the Central Arid Zone was more suitable for spring wheat than winter wheat.(3) The dry and hot wind disaster for winter wheat and spring wheat occurred more often in the Yellow River Irrigation District and the Central Arid Zone, which frequency increased in the whole research area. For spring wheat, the frequency of frost injury was higher in the Yellow River Irrigation District and the Central Arid Zone, but lower in the Southern Mountain Area. For winter wheat, it was higher in the north and lower in the south. During the past50years, it decreased. The freezing injury of winter wheat was higher in the south and lower in the north, and its trend declined in volatility during the past50years. Winter wheat had more agro-meteorological diaster types than spring wheat’s in the growing season, and the disaster risk was higher than spring wheat’s. For spring wheat, the disaster risk in three agriculture ecological zones vary different characteristics. It was highest in the Yellow River Irrigation District, but lowest in the Southern Mountain Area, so it’s more suitable to plant spring wheat in the Southern Mountain Area in Ningxia. For winter wheat, the disaster risk in three agriculture ecological zones were similar in Ningxia. Over the past50years, besides the Southern Mountain Area, the disaster risks for both winter wheat and spring wheat increased. In comparison, the increased trend of disaster risk for spring wheat was more than the winter wheat’s.