黄土塬区不同地膜覆盖度下土壤水热状况研究

为进一步优化覆膜种植模式、了解作物增产机制,比较了黄土塬区无作物种植的旱作农田垄沟条件下土壤水热状况对不同地膜覆盖度(30%,50%,70%,85%,100%,CK即0%)的响应特征。结果表明:(1)地膜覆盖保水效果(Y,4—9月土壤贮水增量)与覆盖度(X)呈正相关关系,拟合方程为Y=1.65 X+42.60,相关系数R=0.98;地膜覆盖度越大,5m土层内有效蓄积降水量越多;覆膜条件下降水入渗土壤的深度已到3m以下。(2)土壤表层温度随覆盖度的增大而升高,有助于低温季节作物出苗;85%膜地温与全膜基本相近。地膜覆盖度从30%增加到85%过程中,白天地温达到峰值的速度加快,峰值加大。(3)综合考虑农田覆膜栽培的土壤水热状况及经济效益,以85%地膜覆盖为最佳选择。

Soil Hydrothermal Status Under Different Degrees of Film Mulching Coverage on the Loess Tableland

In order to further optimize film planting patterns and understand crop production mechanisms,responsive characteristics of soil hydrothermal status to different degrees of film mulching coverage (30％,50％,70％,85 ％,100％,and CK or 0％) were studied under the condition of dry farmland furrows with no crops on the loess tableland.The results showed that:(1) the water conservation effects (Y,the increment of soil water storage from April to September) were correlated with film coverage (X),the fitted equation was expressed as Y =1.65X+42.60,with a correlation coefficient of R =0.98;the greater film coverage was,the more validness of precipitation accumulation in 5 m soil profile was,the depth of rainfall infiltration under the film mulching condition was 3 m below the soil surface;(2) soil temperature increased with the increment of film coverage,which was good for crop emergence in low temperature season;soil temperature for the 85％ mulching was almost the same as the whole-film mulching,ground temperature reached a maximum faster,with a higher peak value from the 30％ of film mulching to 85％;(3) the 85％ of film-covering was best pattern in terms of soil hydrothermal status under film mulching cultivation and economic benefits in farmland.