湖南亚热带丘岗区稻田生态系统水分平衡研究

WATER BALANCE OF PADDY ECOSYSTEM ON SUB-TROPIC HILLY LAND IN HUNAN

作为亚热带丘岗区水资源的降雨资源较为丰沛,而且与水稻的生长季比较吻合,但是,降雨在水稻的生长期内分布不均以及降水频率的变率大,使得水稻在生长期内出现水分的盈亏现象。总的来说早稻表现为水分盈余态势,晚稻则表现为水分亏缺态势,特别是8、9月份会出现严重的水分亏缺。因此,灌溉是必不可少的,灌溉水主要是满足晚稻的生产,占总灌溉水量的71%。

Precipitation, which is the dominant water resources, is sufficient in subtropic hillyland in Hunan Province. A great amount of meteorological data during 1960～2000 and irrigation data during 1989～2000 in paddyfield are analyzed. The results show that the water requirement of the paddyfield is a little more than the rainfall in the whole growth period. During the 1st ten days to the 9th ten days which is mainly corresponding to the growth period of early rice, the water requirement can be sufficiently met by rainfall, however, from the 10th ten days, the water consumption exceeds the rainfall, and especially in August and September the water deficit reaches 2126mm. The annual irrigation quota is 5838m3/hm2 , 71% of which is supplied to late rice. The situation is caused by the uneven distribution and the unsteady frequency of precipitation.