膜下滴灌土壤湿润区对田间棉花根系分布及植株生长的影响

滴灌条件下的土壤湿润区与作物根系分布和植株生长之间的关系是确定滴灌湿润比的理论依据。以大田膜下滴灌试验为基础，在灌水量相同的情况下，通过调控滴水流量得到不同的土壤湿润区，对不同土壤湿润区下的田间棉花根系分布及株高和叶面积生长均匀性进行了试验研究。结果表明，小的滴水流量形成窄深型土壤湿润区，其土壤水分水平分布均匀性较差，使田间棉花根系分布和植株生长均匀性低；而大的滴水流量形成宽浅型土壤湿润区，其土壤水分水平分布均匀性较好，使田间棉花根系的分布和植株生长均匀性较高；膜下滴灌条件下，宜采用宽浅型土壤湿润区。

Effect of soil wetting pattern on cotton-root distribution and plant growth under plastic mulched drip irrigation in field

The relationships between soil wetting pattern and crop-root distribution as well as plant growth under drip irrigation are the theoretical bases for determining the soil wetted percentage in design of drip irrigation system. Based on the field experiments with the plastic mulched drip irrigation, diverse soil wetting patterns were gained by regulating the dripping discharge on dripping plots with the identical irrigation water. By which the distribution of cotton root system was studied as well as the growth process of cotton plant in the inner and outer rows. The experimental results indicated that the narrower-deeper-type soil wetting pattern in consequence of small dripping discharge resulted in lower uniformity of horizontal soil moisture, therefore resulted in lower distribution uniformity of cotton root system in soil and plant growth in field. While the wider-shallower-type soil wetting pattern in consequence of larger dripping discharge resulted in higher uniformity of horizontal soil moisture and higher distribution uniformity of cotton root system in soil and plant growth in field. The wider-shallower-type soil wetting pattern was appropriate to the plastic mulched drip irrigation technique.