长期膜下滴灌农田土壤盐分时空变化

为了探讨长期膜下滴灌对农田土壤盐分演变的影响,该文以一块采用膜下滴灌技术13a的农田为例,对其土壤盐分的时空变化进行比较,分析了该农田土壤盐分演变特征。膜下滴灌技术使用初期,田间土壤盐分含量明显下降,随后其下降幅度减小;随着膜下滴灌年限的延长,田间土壤盐分含量稳定在某一水平范围内。观测结果表明,经过13a的膜下滴灌,田间0～100cm土层盐分质量分数由原来的20～30g/kg降到了5g/kg以下;地头裸地20cm深度以下的土壤盐分质量分数稳定在5～10g/kg,大于田间的相应值;但是地头裸表层土壤盐分质量分数大于20g/kg,存在盐分表聚现象。研究表明,土壤湿润锋处的盐分积累现象不会造成整个土层的盐分含量增高。该文研究结果可为膜下滴灌技术的科学利用提供参考。

Spatiotemporal variation for soil salinity of field land under long-term mulched drip irrigation

A field that has been irrigated with mulched drip technique for 13 years was selected for researching on the effects of the long-term utilization of mulched drip irrigation technique on the evolution of soil salinity distribution. Based on the spatiotemporal variation of soil salinity distribution, the soil salinity evolution characteristics were analyzed. It was found that the soil salinity of the field was decreased substantially during the initial stage of utilizing the mulched drip irrigation, then the decrease rang was declined with the using of irrigation technique; ultimately a stable soil salinity was obtained in the field. After 13 years irrigation with mulched drip technique, soil salinity in 0-100 cm soil layer of the researched field had been declined from 20-30 to 5 g/kg, and that below 20 cm soil depth of the field margin was stable at 5-10 g/kg, which was larger than that in the corresponding soil layer of the field. But soil salt assembled at the surface of the field margin resulted in that soil salinity at the surface of field margin was larger than 20 g/kg. The salinity of entire soil layer in the field land could not be increased by the salty accumulation at soil wetting front. The study provides a reference for the reasonable use of mulched drip irrigation technique.