棉花需水量研究初报

本项研究采用排水式蒸渗器对江西中、低两种种植密度棉花的需水量进行了研究。研究结果表明：低密度棉花需水量７２４．４ｍｍ，中密度棉花需水量７５０．２ｍｍ，需水量随种植密度的提高而增加。低密度皮棉产量１１４３．６ｋｇ／ｈｍ２，需水系数为６３３４．４，中密度皮棉产量为１１３４．４５ｋｇ／ｈｍ２，需水系数为６６１３．４，表现为随着棉花产量的提高，需水系数反而下降。研究还发现冬季变暖的年份使棉花生育期较正常年份延长，需水量增大，其影响关系有待于进一步深入研究。

A Preliminary Report on the Water Demand Sum of Cotton

The water demand Sum of medium and low planting density of cotton were studied in this paper by using like-drained lysimeters.Results indicated that the water demand sum of low and medium planting density of cotton were 724.4 mm and 750.2 mm, respectively. The water demand sum of cotton increased with the increasing of planting density. The yield of ginned cotton was 1143.6 kg/hm 2 in the low planting density fields and water demand coefficient was 6334.4. The yield of ginned cotton was 1134.45 kg/hm 2 in the medium planting density fields and water demand coefficient was 6613.4. The results showed that water demand coefficient decreased with the increasing of yield of ginned cotton. It was also discoveried that the growth duration of cotton is longer in warmer winter than that of cotton in normal winter and the water demand sum is larger in warmer winter than that in normal winter. Relations between the growth duration of cotton and the water demand sum isn't clear and make a thorough study.