绿洲棉田长期连作下残膜分布及对棉花生长的影响

通过田间调查和长期连作定点微区试验相结合,研究了长期连作棉田,集中连续使用地膜后,地膜在土壤中的累积、空间分布和形态变化,及其残膜对土壤物理性状、棉花根系生长及产量的影响。结果表明:随着地膜使用年限增加土壤中残膜平均每年以11.2kg·hm-2速率增加,长期连作棉田残膜主要分布在0～30cm土层,占到了85%,在耕作层(0～30cm)以下随着根层深度的增加,残膜量减少;大于50cm2残膜在土壤中平均占30%,10～50cm2占36.5%,小于10cm2占33.4%,随连作年限增加,在0～15cm土层残膜量减少,15～30cm土层残膜量逐渐增加,残膜破碎度提高。土壤孔隙度、田间持水量随着地膜残留量增加而增加,而土壤容重下降。棉田中残膜阻碍棉花主根垂直生长,使根系形态呈现鸡爪型和丛生型等畸形,但对棉花产量未造成影响。

The Distributing of the Residue Film and Influce on Cotton Growth Under Continuous Cropping in Oasis of Xinjiang

Accumulation, distributation and shape change of residue film in soil, its effect to soil physical character, the growth of cotton's root and yield of cotton were studied by field investigation and fixed-point trial in the continuous cropping field. The re8ult showed that acco-mount of residue film was increased with 11.2kg·hm~(-2),residue film was mostly distributed in 0～30cm in long-term continuous cropping cot-ton field, accomunting for 85%, proportion of residue film was continually decreased with the root-layer adding below 0～30 cm. More than 50 cm~2 film was 30%, from 10 to 50 cm~2 was 36.5%, and less than 10 cm~2 film was 33.4%. With increasing of continuous cropping years, number of residue film was droped accordingly in 0～15 cm, and it was gradually increased in 15～30 cm and the shatter ratio of residue film was en-hanced. The soil porosity and field capacity were increased with the content of residue frlm increasing, but the soil bulk density was de-creased. The Residue film in soil can inhibit the vertical growth of the roots and force it to form okra roots and cluster roots, but it didn't affect cotton's yield.