摘要
根据定位点的实测资料，阐述了南亚热带丘陵赤红壤试区的降雨、蒸散、地表径流、深层贮水和土壤贮水量的动态变化在土壤水分循环中的作用。研究结果表明，在丘陵赤红壤水分循环中，降雨量多和降雨强度大起着极重要的作用，降雨量多但分配不均匀形成明显的干湿季节，降雨强度大于土壤入渗速率是产生地表径流的关键条件。由大雨而暴雨并持续１０ｈ以上的降雨过程且降雨超过５０ｍｍ，将产生深层贮水。在干旱季节（１～２月和１０～１２月），降雨量仅占年降雨量１１．６１％～１６．４６％，而蒸发量却占年总蒸发量３３．２２％～４２．０８％，尤其是每隔两年左右的１月或１１月前后，常出现持续４０多天未下雨的现象，０～１００ｃｍ土层的蒸散量大于降水渗入量、土壤贮水减量。因此，在雨季防止或减少地表径流；在旱季减缓土壤水分蒸发，提高土壤水分利用率，或以喷灌方式补充土壤水分，是丘陵区发展“三高农业”不可忽视的问题。
Based on the observational material from the experimental plots, we describe the roles of dynamic changes in rainfall, evapotranspiration, surface runoff, subdrainage and soil water storage on soil water cycle in latosolic red soil. The observational results show that the large amount and the high intensity of rainfall play a very important role in the soil water cycle. The large amount and uneven distribution of rainfall forms obvious wet and dry seasons, high intensity of rainfall is a key condition to produce surface runoff. The over 10 hours'rainfall duration with more than 50mm rainfall will produce subdrainage. In the dry seasons (from January to February and from October to December), the rainfall only accounts for 16.46% of annual rainfall, but the evaporation makes up 42.08% of annual evaporation, especially, in January or November per interval two years, there is often no rain lasting about 40 days, so the evapotanspiration from 0～100cm soil profile is larger than the rainfall infiltration, and soil water storage is decreased. Therefore, preventing or decreasing surface runoff in rainy seasons, keeping down soil water evaporation in dry seasons, and enhancing soil water use rate or supplying soil water by spray irrigation, should not be ignored questions in developing 'three-high' agriculture.
基金
国家自然科学基金
