地下水位下降对干旱区膜下滴灌棉花需水量的影响

Effect of ground water level decrease on cotton water demand by mulched drip irrigation in arid area

膜下滴灌种植方式大面积在西北干旱地区推广应用,使得该区地下水得不到有效补给,地下水位出现大幅下降。水位下降使地下水对土壤水的顶托作用和潜水的蒸发作用减弱,对作物需水量产生一定影响。利用2008~2018年新疆巴音郭楞蒙古自治州国家重点灌溉试验站不同地下水位进行滴灌实验的有利条件,研究地下水位下降对干旱地区膜下滴灌棉花滴灌水量的影响,并使用Penman-Monteith公式计算地下水埋深7~8 m时膜下滴灌棉花的需水量。研究表明:地下水位下降致使干旱地区的膜下滴灌棉花高产的需水量上升;滴灌水的入渗能力具有随矿化度增加而增加的趋势,且适宜的含盐量对棉花的生长具有一定的协同作用;当地下水埋深大于6 m时,水位的进一步下降将不再促使膜下棉花的需水量进一步上升。

Mulched drip irrigation is widely used in arid area of northwest China, which makes the groundwater in this area cannot effectively recharged and the groundwater level drops sharply. The decrease of water level weakens the supporting effect of ground water on soil water and the evaporation from phreatic aquifer, and has a certain impact on crop water demand. In order to research the influence of decreased underground water level on cotton water demand by mulched drip irrigation, with the help of the favorable conditions in the state key irrigation experimental station of Xinjiang Bayinguo Mongol Autonomous Region prefecture from 2008 to 2018 at different groundwater levels, a drip irrigation experiment was carried out and Penman-Monteith formula was used to calculate the cotton water demand by mulched drip irrigation when the groundwater depth was 7-8 m. Results showed that the decrease of groundwater level leads to an increase of water requirement for high yield of cotton water demand by mulched drip irrigation in arid area. The infiltration capacity of drip water increased with the increase of salinity. The appropriate salt content has a certain synergistic effect on the cotton growth. When the local water depth is deeper than 6 m, the further decrease of water level will not increase the cotton water demand.