残留地膜对土壤污染及棉花生长发育的影响

棉田地膜覆盖栽培技术的广泛应用，残留地膜对土壤污染逐年大幅度的增加，试验结果表明地膜残留于土壤中使土壤物理性状恶化。主要表现在土壤水份下渗和上渗系数降低。使棉田出苗率降低，死苗率上升，改变了植株根系在土壤中的分布形态，使主根下扎深度变浅，不利于根系对土壤深层水的吸收利用，造成一定程度上的减产。虽然目前棉田地膜残留量尚未对棉花产量构成明显影响，但对自然环境污染程度已成为不容忽视的问题。

Contamination of Film-remnant to the Soil and Its Effect on the Cotton Growth and Development

As the contamination of film remnant in cotton filed increasing year after year,more and more people are concerning this proplem.Since 1989,a lot of investigations on the contamination degrees have conducted.Experiments have also been done to test whether the different film remnant affect the soil physical characteristics,cotton development and the cotton yield. The results showed that the film remained in the soil deteriorated the siol physical features,i.e.,the penetra tion and evaporation coefficients of soil water fallen down.The film pieces remained in the soil made the shoot-emergence rate decreased,dead shoot rate increased and the cotton root discribation changed in the soil. The main root penetrated shallower,which impeded the absorption of up water from the deeper soil layers when water stress occured, and led to the decrease of yield in certain extent.