黄淮海平原冬小麦生长期旱情分析

黄淮海平原降水较少且年际、季际变化大，因此水分供应状况成为该区作物，特别是以冬春季为主要生育期的冬小麦的主限制因素。鉴于作物实际蒸散量与潜在蒸散量关系依赖于作物生长状况和土壤水分的事实，提出反映作物缺水状况的干旱指标———作物水分胁迫指数（ＣＷＳＩ）。计算黄淮海平原冬小麦生长期间的ＣＷＳＩ，并分析其在自然降水条件及适量灌溉条件下的时空分异规律

ANALYSIS OF DROUGHT DURING THE PERIOD OF WINTER WHEAT GROWTH IN HUANG-HUAI-HAI PLAIN

Based on the fact that the ratio of actual evapotranspiration to potential evapotranspiration depends on the availability of soil moiture and crop growth stages, Crop Water Stress Index ( CWSI ) is submitted to express the crop drought. The CWSI by ten days interval during 11(1980-1991) winter wheat growth years of 60 stations in Huang Huai Hai Plain were calculated in this paper. Then we analyzed the characteristics of CWSI in time and space scale. And the CWSI on the conditions of rain feed and that of irrigation are compared. By contrast of the CWSI and soil moisture index, the CWSI is more sensitive to the deficiency of crop water. Some conclusions are: (1) According to the result of PCA (principal component analysis), the plain is divided into three parts, which are different in the CWSI change process from each other. The southern plain shows drought in March, and the northern plain in the first ten days of February, the before the first ten days of January. (2) Under rain feed the CWSI of the winter wheat in the plain keeps rising from the middle ten days of October to the last ten days of May, while the irrigation can mitigate the drought. (3) In the year with less precipitation the CWSI in the plain is larger and the time of CWSI less than 0.5 is earlier.