残膜对棉田土壤水盐、氮素及产量的影响

为探讨滴灌条件下棉田中地膜残留含量对土壤水盐及作物生长的影响,在棉田设置150(T1),230(T2),465(T3),857(T4),1 250(T5),1 640(T6) kg/hm~2、原试验地土壤(CK1)和无残膜对照组(CK2)8种残膜含量处理,分析了地膜残留含量对滴灌棉田中的土壤水盐、土壤和作物根系氮素以及产量的影响。结果表明:随着残膜含量的增加,土壤含水率逐渐降低,土壤盐分的富集效果逐渐增强;0—40 cm土层土壤水盐变异程度与残膜含量呈正相关,T5和T6的土壤水盐变异系数(CV)明显较大,水分CV分别为0.52,0.44,盐分CV分别为0.34,0.31;土壤中的氮素含量随着残膜含量的增大逐渐增多,根系全氮含量与残膜含量呈负相关;棉花产量随残膜含量的增加逐渐降低,当残膜含量230 kg/hm~2时,下降幅度显著增强,T3、T4、T5和T6较CK2产量分别下降14.19%,21.69%,29.19%,37.29%。研究结果可为新疆覆膜滴灌棉田可持续发展和对残膜污染的防控提供理论基础和科学支撑。

Effects of Residual Film on Soil Water-salt, Nitrogen and Yield in Cotton Field

In order to investigate the effects of residual film content on soil water-salt and crop growth in cotton field under drip irrigation, eight treatments of residual film contents, 150 (T1), 230 (T2), 465 (T3), 857 (T4), 1 250 (T5) and 1 640² kg/hm (T6), original soil (CK1) and no residual film control (CK2), were set in a cotton field. The effects of residual film contents on soil water-salt, soil and crop root nitrogen and yield in drip irrigated cotton field were analyzed. The results showed that with the increases of residual film contents, soil water contents decreased gradually, and the enrichment effect of soil salt increased gradually. The variation degree of soil water and salt was positively correlated with the residual film content in 0-40 cm soil layer, and the Coefficient of variation CV of soil water and salt in T5 and T6 was significantly larger, the CV of water content was 0.52 and 0.44 and salt was 0.34 and 0.31 respectively. The nitrogen contents in soil increased with the increases of residual film contents, and the total nitrogen contents in root were negatively correlated with the residual film contents. The yield of cotton decreased gradually with the increases of residual film contents. When the residual film content was more than 230 kg/hm², the decline was significantly enhanced, compared with CK2, the yield of T3, T4, T5 and T6 decreased by 14.19%, 21.69%, 29.19% and 37.29% respectively. This study could provide theoretical basis and scientific support for the sustainable development of mulched drip irrigation cotton field and the prevention and control of residual film pollution in Xinjiang.