不同灌水技术参数对农田水盐运移的影响

【目的】探索滴灌条件下农田高效洗盐适宜灌溉指标。【方法】通过人工控水试验重点研究了不同滴头流量(2.8和5.6L/h)和灌水定额(22.5、37.5和52.5mm)对盐碱地棉花根区盐分淋洗效果的影响。【结果】同一灌水定额条件下,湿润锋半径随着滴头流量的增加而增大;滴头流量增加,土壤水分分布呈宽浅型,表层土壤含水率逐渐升高。同一滴头流量条件下,湿润锋半径随着灌水定额的增加而增大;土壤含水率随着灌水定额的增加而增大。表层土壤盐分随着滴头流量和灌水定额的增大而减小,滴头流量为2.8 L/h时,水平脱盐半径30 cm,垂直脱盐深度60 cm;滴头流量为5.6 L/h时,水平脱盐半径40 cm,垂直脱盐深度40 cm。【结论】灌水定额52.5 mm时,脱盐效果最佳;随着作物的根部伸长,改变滴头流量,扎根40 cm以内用滴头流量5.6 L/h,扎根超过40 cm用滴头流量2.8L/h,可作为适宜的灌水技术参数。

Effects of Drip Irrigation Schedule on Water and Salt Movement in Soil

【Objective】Salt movement and accumulation in soil is modulated by rainfall and irrigation.This paper aims to elucidate the impact of drip irrigation schedule on water and solute movement in a farmland soil.【Method】The experiment was conducted in a saline-alkali rooted soil,and we compared three two dripping rates(per emitter):2.8 L/h and 5.6 L/h,and three irrigation amounts:22.5 mm,37.5 mm and 52.5 mm(per emitter).【Result】When the irrigation amount was the same,increasing dripping rate increased the radius of the wetting front,and made the moisture distribution broader and shallower and the surface soil more moist.When the dripping rate was the same,increasing irrigation amount increased both the radius of the wetting front and soil water content.Soil salinity in top 50cm soil layer increased with dripping rate and irrigation amount;the desalination radius and desalination depth were 30 cm and 60 cm respectively when the dripping rate was 2.8 L/h,and 40 cm and 40 cm respectively when the dripping rate doubled.【Conclusion】Our results showed that the desalination was best when dripping rate was 5.6 L/h and irrigation quota was 52.5 mm.