干旱地区棉田膜下滴灌盐分运移规律

Salt transfer law for cotton field with drip irrigation under mulchin arid region

以田间实测数据为基础,研究棉田膜下滴灌对土壤盐分的变化。通过对棉田4个不同的生育期以及不同滴灌年限棉田盐分的变化进行了分析,初步得到,棉田在生育期盐分变化特征是0～20cm含盐率从播前到苗期减小、盛铃期增大、吐絮期减小的趋势,>40～80cm从播前缓慢增加、盛铃期～吐絮期逐渐减少;水平方向滴头处盐分累积最少,膜间处盐分累积较多;垂直方向上0～20cm土层盐分减少,>60～100cm土层累积程度较大;不同滴灌年限棉田随滴灌年限的延长各层土壤含盐率相应增加并且在>60～100cm增加的趋势显著,且滴头、行间、膜间的总含盐率是依次增加;>60～100cm已成积聚盐分的最大区域;在棉花生育期内,0～60cm土壤呈脱盐状态,60～100cm土壤呈积盐状态。该结果可为干旱区棉花膜下滴灌水盐的治理与防治提供参考。

Based on measured date in field,the soil salt changes for cotton field with drip irrigation under the plastic mulch were investigated.Through analyzing the salinity changes in cotton field with different irrigation years in four different growing period,it was concluded that salt content in soil depth 0-20 cm was reduced during before planting,seedling stage,and the boll opening period,but increased during the blooming-bolling stage.Salt content in 40-80 cm increased slowly during before sowing and reduced during the blooming period and boll opening period.The accumulation of salt at emitter was less than that at any other position but more at interspace of films in horizontal direction.The accumulation of salt in 0-20 cm of vertical direction reducted,but in the 60-100 cm it was larger.Meanwhile with the drip irrigation time extension,soil salt content would increase,especially in the 60-100 cm,the increasing trend was significant.At the location of emitter,inter-lines and inter-films,the total salt content would increase successively.The zone of 60-100 cm was of largest salt accumulation.In the cotton growth period,the depth of 0-60 cm soil kept desalting state,and the depth of 60-100 cm soil appeared depositing salt state.The results can provide references for management and prevention of drip irrigation water and salt under mulch in arid regions.