农田蒸散,土壤蒸发与水分有效利用

本文通过试验研究和模型模拟，对作物生长期间的水分条件，作物蒸散规律，土壤蒸发占蒸散的比例，覆盖的节水效应和灌溉对作物生长的影响进行了研究，对如何科学合理有效地利用水分提供依据。

EVAPOTRANSPIRATION, SOIL EVAPORATION AND WATER EFFICIET USE

Agricultural water use, i.e. field evapotranspiration includes crop transpiration and soil evaporation. Studies on field evapotranspiration, ratio of transpiration and soil evaporation, and agronomic measures for controlling soil evaporation are the important aspects of the researches on field water efficient use. During the period of 1984 to 1996, several field experiments have been carried out at Luancheng Agricultural Ecosystem Station to measure water balance components, crop physiological parameters. Based on the experimental research and model simulation, the water conditions for crop growth, relationship between evapotranspiration and soil evaporation, effects of mulching on soil evaporation, and effects of irrigation on crop growth were analyzed in this paper, which would provide the scientific basis for efficient water use. From the experiments, it was known that soil evaporation accounted for 29.0% of the field evapotranspiration during wheat growth season, which showed the potential for reducing soil evaporation. It was clear that mulching could effectively control the soil evaporation. Wheat stubble could prevent soil evaporation in corn field by 34.7%, and the mulching with crop straw could reduce soil evaporation by 50%. The time and rate of irrigation affect the availability of irrigation water. The simulation results of WAVES showed that there was no agricultural production without irrigation in the dry year in this region, while developing dryland agriculture would be practical when several succesive wet years happened.