地膜棉翻膜放苗的棉田微生态效应

对地膜棉翻膜放苗的棉田微生态效应研究表明,翻膜放苗地膜的有效覆盖度比打孔放苗增加30%～45%,增强了对棉田水温变化的影响,翻膜放苗可明显提高大行地温,且对提高和稳定小行地温也有良好的效应。放苗初期,小行土壤含水量略低于对照,有利于解决地膜棉易出现高脚苗旺长问题。翻膜放苗后加剧了土壤空隙中水汽的膨缩运动,大行土壤容重平均比对照降低0.12g·cm-3,土壤疏松,水、气、热较为协调,耕层土壤微环境得到改善,为增强根系活力和扩大吸收范围创造了条件。有效覆盖度的增加增强了覆盖的反光效应,有利于提高近地层光照强度和棉株制造光合产物的能力,并增大了苗期对蚜虫迁入的拒避作用。

Effect of releasing cotton seedling by turn-over plastic film on micro-ecological system in plastic-mulched cotton field

The effect of turn-over plastic film from narrow row(cotton seeding row) to wide row(space between cotton seedling row) to release cotton seedling on micro ecological system was investigated using comparison with withholding and holing plastic film to release seedling(control). The results show that effective coverage rate of plastic film increases by 30% ~ 45% in turn over plastic film to release cotton seedling, compared with withholding holing plastic film to release seedling, as it strengthens regulating effect on moisture-temperature in cotton fields. After seedling release by turn-over plastic film, the soil temperature increases in wide rows, and become stabe in narrow row; the soil water content reduces below that in the control; but steam movement increases compared with the control. This is beneficial to preventing seedlings from outgrowth and developing of microbes which strengthens root nutrient absorption, but more importantly, to reducing soil bulk density by 0.12 g·cm^-3. Light reflection, light strength near soil surface increase and cotton plant photosynthetic rate increases as well, which prevents aphis gossipii glover migration.