模拟降雨条件下覆盖方式对冬小麦降水利用的影响

Effect of Different Covering Methods on Rainfall Use of Winter Wheat Under Simulated Rainfall

人工模拟降雨条件下,在大田设置地膜覆盖(PM)、4种秸秆覆盖量(覆盖量分别为1 500,4 500,7 500,10 500kg/hm2,即SM15、SM45、SM75和SM105),同时设置无覆盖处理作为对照(CK),研究不同覆盖方式对雨后冬小麦棵间蒸发量、土壤剖面水分和降雨土壤蓄积量的影响。结果表明:各处理雨后冬小麦逐日棵间土壤蒸发累积量和日变化有相同变化趋势;同一时间段内不同覆盖处理的土壤蒸发差异明显,各生育阶段土壤累积蒸发量和日蒸发量均表现为SM105<SM75<PM<SM45<SM15<CK;冬小麦群体冠层结构对雨后土壤蒸发量影响显著,同等降雨条件下,相同处理拔节期前蒸发量明显大于拔节期后的。各处理因降雨和冬小麦蒸散作用而引发的土壤含水量波动趋势基本一致,即不同土层深度土壤含水量随时间推移先增加后下降,但不同覆盖处理间0-100cm土层剖面含水量差异明显,其中PM的最小,CK的次之,SM105的最大;降雨土壤蓄积量整体也表现为:SM105>SM75>SM45>SM15>CK>PM;受植株冠层降雨截留量增大的影响,冬小麦拔节期后各处理的土壤含水量和降雨土壤蓄积量明显低于拔节期前的。研究结果可为提高冬小麦农田自然降水的利用率,促进节水农业的发展提供基础理论依据。

By setting plastic mulching （PM）, 1 500, 4 500, 7 500, and 10 500 kg/hmz of straw mulching quantiy respectively （SM15, SM45, SM75 and SM105）, also setting no mulching as control treatment （CK） in winter wheat field, under simulated rainfall situation, the influence of different covering methods on soil e- vaporation, soil moisture and rainfall storage by soil were studied. The results indicated that the daily varia- tions and daily cumulative of soil evaporation had the same trend in all treatments; the difference of soil evap- oration with different covering methods was significant in the same period, the daily and accumulative soil e- vaporation volume at each growth stage showed SM105 〈 SM75 PM〈 SM45-（ SM15 〈 CK winter wheat canopy structure affected on soil evaporation after the rain significantly, under the same rainfall condition, soil evaporation of before the jointing stage was significantly greater than after the jointing stage with the same treatment. The treatment for rainfall and evapotranspiration of winter wheat caused fluctuations in soil moisture content presented the same tendency, namely, soil moisture contents in different soil depth in- creased over time first, then decreased. But the differences of soil moisture with all treatments among the 0 -100 cm soil layers were significant, including the smallest PM, CK followed, SM105 maximum~ rainfall storage by soil also expressed as. SM105〉SM752〉SM45〉SM15〉CK〉PM; by canopy interception increas- ing, the amount of soil moisture and rainfall storage by soil of winter wheat with all treatments after jointing stage was significantly lower than that before the jointing stage. The results could provide theoretical basis for improving the utilization of natural rainfall and promoting water-saving agriculture in winter wheat field.