不同留茬覆盖模式对土壤蒸发和表层土壤含水量的影响

秸秆覆盖模式可显著影响土壤蒸发量和土壤含水量。本研究根据小麦机械收获的特点,设置不同的小麦留茬高度和覆盖量,研究了不同留茬高度和覆盖量组合对冬小麦收获后土壤表层含水量和土壤蒸发量的影响。试验结果显示冬小麦留茬高度0~35 cm对表层土壤含水量和土壤蒸发影响较小,而覆盖会明显改善土壤含水量和降低土壤蒸发量。当留茬高度为0~15 cm、田间剩余秸秆覆盖量为0.348~0.470 kg/m2时,试验期间(31 d)土壤累积蒸发量较无覆盖减少了16%~51%。考虑机收特点,建议小麦留茬高度为5~15 cm,其余残留碎杆覆盖在土壤表面,以减少土壤蒸发和提高水分利用效率。

Effects of stubble and mulching modes on soil evaporation and soil water content

Straw mulching has important effects on soil evaporation and soil water content. Different stubble height and mulching quantity was set to study the effects of these practices on soil water content and soil evaporation after winter wheat harvest.The results showed that remaining stubble height of 0～35 cm had minor effects on soil water content and soil evaporation.However,mulching practices caused a significant reduction of soil evaporation.During the experimental period(31 d),the total amount of soil evaporation reduced by 16%～51% under mulching quantity of 0.348～0.470 kg/m2 as compared to no mulching when stubble height was 0～15 cm.In consideration of the feasibility of machine harvest for wheat, the recommended mode is leaving stubble height of 5～15 cm and mulching remaining straw on soil surface,so as to reduce soil evaporation and increase soil water use efficiency.