黄土塬区降水变化条件下冬小麦田土壤水分消耗与补给

通过人工实时降水分配试验,研究了黄土塬区冬小麦田3种降水条件:正常降水(R_(CK))、降水增加1/3(R_(+1/3))和降水减少1/3(R_(-1/3))下,土壤水分变化速率、消耗深度以及水量平衡状态。结果表明:R_(CK)和R_(-1/3)处理0~3.8 m土层土壤储水量以91.85 mm·a~(-1)和109.39 mm·a~(-1)的速度下降,而R_(+1/3)处理土壤储水量在0~3.0 m深度以48.94 mm·a~(-1)的速度减少,而在深层(3.0~3.8 m)土壤水以17.39 mm·a~(-1)的速度增加;降水增加使得土壤水分的补给次数增多,减少了土壤水分的时空变异;当土壤底墒充足且生育期降水量较多时,各降水处理土壤水分的消耗深度较浅,反之,则较深;在休闲期,降水的转化效率与生长季土壤水的消耗率呈现极显著的指数相关。

Soil moisture consumption and replenishment in winter wheat land under the conditions of precipitation change in loess plateau

The soil water consumption and replenishment was the combined action of crop water use and precipitation, it was possessed important value for estimation and prediction of soil water resources. In this paper through the artificial real-time precipitation allocation experiment, has researched the soil water change rate, consumption depth and soil water balance status under three precipitation conditions as: normal precipitation (R_CK), precipitation increased 1/3 (R_+1/3) and precipitation decreased 1/3 (R_-1/3) of winter wheat land in loess plateau. The results indicated that: The soil water storage in 0~3.8 m depth was reduced with the velocity of 91.85mm·a^-1 and 109.39mm·a^-1 for the treatments of R_CK and R_-1/3, but for the treatment of R_+1/3, Soil water storage decreased at the speed of 48.94 mm·a^-1 within 0~3.0 m depth and increased within 3.0~3.8 m depth with the velocity of 17.39 mm·a^-1. Increasing of precipitation makes the supply of soil moisture more frequent, thus reducing the temporal and spatial variation of soil moisture. When the soil water content before sowing was sufficient and the precipitation in growing season was more rich, the soil water consumption depth for each treatment was shallower, on the contrary, the consumption depth was deeper. During fallow period, the transformation efficiency of precipitation with the soil water consumption rate was appeared an extremely significant exponential correlation.