关键词: 需水量, 水分亏缺指数, 时空特征, 春玉米

Abstract:

Crop water surplus deficit index (CWSDI) is one of important indexes to distinguish drought degrees of crop. So the analysis of temporal and spatial distribution of CWSDI is with realistic significance to guide the reasonable distribution of crop and scientific and effective irrigation. Based on the observation records during the growing periods of spring maize and daily precipitation, temperature and wind speed data at 24 weather stations of central Inner Mongolia and so on during 1971-2015, the water requirement of crop was calculated by using Penman-Monteith equation. Combined with the effective precipitation, the water surplus deficit was calculated. And on this basis the temporal and spatial distribution characteristics of CWSDI of spring maize in central Inner Mongolia were analyzed quantitatively. The results showed that CWSDI during the growth period of spring maize in central Inner Mongolia presented a fluctuant change of falling first and then rising. CWSDI of crop appeared weak dropping trends in the early stages and the late stages of growth in central Inner Mongolia during 1971-2015, while it appeared rising trend in the middle stages, and the rising trend was obvious from the tasselling to milk-ripe stage of spring maize, especially it reached significant test of 0.05 level after the 1990s, which indicated that CWSDI increased in the critical period of water requirement of spring maize. The mutation of CWSDI from the tasselling to milk-ripe stage happened in 1991. In space, CWSDI of spring maize presented a zonal distribution with higher in the north and lower in the south of central Inner Mongolia, which was related with precipitation distribution with more in the south and less in the north.

Key words: water requirement, water surplus deficit index, temporal and spatial distribution characteristics, spring maize