小麦/玉米间作畦沟分灌土壤盐分迁移特征

Characteristics of Soil Salt Transfer Under Intercropping and Border-Furrow Irrigation Pattern

针对内蒙古河套灌区小麦/玉米间作常规灌溉模式下农田灌溉水浪费严重、土壤盐碱化日益加剧等农业生产现状,结合垄作沟灌技术,在灌区开展小麦/玉米间作畦沟分灌,并对畦灌和畦沟分灌两种灌水模式下间作群体作物根系区土壤垂向剖面内盐分的动态平衡进行了对比分析。结果表明:间作群体整个生育期,经历多次灌溉后,并未将土壤盐分有效排除农田,反而在灌溉及矿质化地下水补给作用下表现为积盐态势,将灌溉水及矿质化地下水携带的盐分聚集在根区土壤中,畦灌和沟灌玉米田单位面积土体储盐量平均增加211.08 g/m^2,300.34 g/m^2,差异显著。常规畦灌小麦田和畦沟分灌小麦田储盐量分别增加202.91 g/m^2,200.43 g/m^2,差异性不显著。畦灌和沟灌玉米土壤储盐量变化分别以0—60 cm和20—60 cm最大,且沟灌玉米整个生育期耕层0—20 cm土壤处于积盐状态,小麦各土层储盐量变化则以0—40 cm最大。研究结果可为畦沟分灌技术在河套灌区的推广应用提供技术支撑。

In view of serious water waste and increasing soil salinization in the present agricultural production situation for the wheat/maize intercropping conventional irrigation pattern in Hetao Irrigation District. On the basis of ridge furrow irrigation technology, the wheat/maize intercropping border-furrow irrigation technology was first put forward. The dynamic equilibrium of soil salinity in the vertical section of crop root zone in intercropping population under two irrigation patterns was compared. The results showed that the intercropping group had not effectively eliminated the soil salt after several irrigations in the whole growth period, instead, under the effect of irrigation water salt and mineralized groundwater recharge, the salt accumulation situation was obvious;the soil salt storage for border and furrow irrigation maize field increased by 211.08 g and 300.34 g per unit area on average;salt storage increased 202.91 g and 200.43 g, respectively, the conventional irrigation and border-furrow irrigation wheat, the difference was not significant. By quantitative analysis of salt content in soil profile, it was found that the change of soil salt content in border irrigation and furrow irrigation maize was the largest for 0—60 cm layer and 20—60 cm layer, respectively, and furrow irrigation maize was in the state of salt accumulation in the surface soil of 0—20 cm in the whole growth period. The change of salt storage in each soil layer of wheat was the largest for 0—40 cm. The research results can provide technical support for the application of border-furrow irrigation technology in Hetao Irrigation District.