基于电磁感应的不同膜灌模式下棉田土壤盐分分布研究

选择“1 膜1 管4 行”(114 模式)、“1 膜2 管4 行”(124 模式)以及覆膜漫灌3 种不同膜灌模式下典型棉田地块点位, 同时测定膜上宽行(W)、膜上窄行(N)以及膜间(I)3 个位置不同离地高度的大地表观电导率(EC_a), 建立不同土层深度盐分含量解译模型, 研究不同膜灌方式下盐分的垂直和水平分布特征。研究结果表明: 水平方向上, 0~10 cm土层, 114 模式下膜上窄行盐分含量高于宽行, 124 模式下膜上窄行盐分含量低于宽行,漫灌模式下膜上宽行和窄行盐分含量差异不大; 垂直方向上, 3 种模式下盐分均呈现一定的表聚趋势, 盐分最大值出现在10~20 cm 土层, 80 cm 以下土层土壤盐分含量趋于稳定。基于电磁感应建立的土壤剖面盐分解译模型具有良好精度, 方便快捷, 可实现不同膜灌方式下棉田土壤盐分分布的快速预测, 对指导农业生产具有重要意义。

Determining soil salt distribution by electromagnetic induction of cotton field under different film-mulched irrigation techniques

Specific field sites in cotton field were selected for different film-mulched irrigation techniques, including one-mulch/one-pipe/four-row irrigation mode (114 mode), one-mulch/two-pipe/four-row irrigation mode (124 mode) and flooding irrigation mode (FIM). Then apparent electrical conductivities (EC_a) were measured at different heights and locations of the sites, including wide-row with mulch, narrow-row with mulch and inter mulch. Soil profile salinity interpretation models were established to evaluate the horizontal and vertical distribution characteristics of soil salt. The study showed that, in horizontal direction, soil salt content in narrow-row with mulch was more than that in wide-row with mulch in 114 mode in the 0~10 cm soil layer. Under 124 mode, soil salt content in narrow-row with mulch was less than that in wide-row with mulch. There was no obvious difference at different locations under FIM. In vertical direction, surface accumulation occurred in all three modes (114 mode, 124 mode and FIM). The maximum accumulation occurred in the 10~20 cm soil layer, and soil salt content tended to be stable in layers below 80 cm. Soil profile salinity interpretation models were not only precise in results, but also convenient in use. The models could therefore be used to accurately predict soil salt distribution of cotton field under different film-mulched irrigation techniques. This was significant for improving agricultural production.