膜下滴灌的土壤水分对棉花根长密度分布及产量的影响

Effects of Soil Moisture on the Distribution of Root Length Density and Yield of Cotton under Drip Irrigation

通过膜下滴灌田间试验,研究了水分对棉花根长密度分布及产量的影响。结果表明:各灌水处理棉花根长密度空间分布总特征一致,水平方向,宽行与窄行的根长密度基本相同,但明显大于膜间;垂直方向,随土壤深度增大,棉花根长密度减小。但不同灌水处理间存在差异,过量灌水处理棉花膜间的根长密度增大,宽行与窄行的根长密度减小,随着灌水量的增加,棉花全根层平均根长密度增大;胁迫灌水处理深层土壤中根长密度增大。花铃期、吐絮期各土层棉花根长密度与产量呈显著的二次相关关系。灌溉量与棉花产量间的关系符合报酬递减规律,其回归方程为y=-0.0026x2+18.015x-24845(R2=0.959)。

Effects of soil moisture on the distribution of root length density and yields of cotton were stud- ied by field experiment under drip irrigation. The results indicate that spatial distribution characteristic of cotton root length density of all water treatments were basically consistent. Horizontally, the cotton root length densities are similar between wide and narrow rows, but are significant higher than bare land; verti- cally, root length density of cotton increased with soil deeps increased. But the distribution of cotton root length density has a significant difference under different water treatments. Water excessive increased cot- ton root length density of bare land, but decreased wide and narrow cotton rows. Root length density of cotton increased with irrigation amounts increased. Water stress increased root length density of deep lay- er. There are a significant correlation between root length density and yields of cotton at flowering and boll opening stage. The regression between irrigation amounts and yields of cotton are y =- 0. 0026x2 ＋ 18. 015x-24845 （R2 =0. 959）. The regression showed that the irrigation amounts of 3464.4 m3/hm2 can access to appropriate root length density and yields of 6360.8 kg/hm2.