陕北黄土高原雨养区谷子棵间蒸发与田间蒸散规律

为了提高黄土高原雨养区谷子的降水利用效率，该文利用中型称重式蒸渗仪和微型蒸渗仪并结合谷子整个生育期内生物指标的动态变化过程，对神木六道沟流域谷子棵间蒸发与田间蒸散规律进行了研究。结果表明，Logistic模型可以很好地模拟谷子株高和盖度的变化，模型计算值与实测值的相关系数均达到0.99。神木六道沟流域的降水总量和谷子的耗水量基本持平，在谷子抽穗期到灌浆期出现了阶段性的缺水。在谷子整个生育期内谷子棵间蒸发占总耗水量的44%。叶面积指数、0～10 cm土层土壤含水率与棵间蒸发与田间蒸散比值间均呈指数函数关系，其决定系数均在0.8以上，且呈现出极显著的相关性。研究为当地合理利用有限水资源和提高水分利用效率提供理论支持。

Rules of soil evaporation and millet evapotranspiration in rain-fed region of Loess Plateau in Northern Shaanxi

For improving precipitation use efficiency of millet in rain-fed region of Loess Plateau, the middle weighing lysimeter, micro-lysimeter and biological indicators were combined in this experiment to determine the soil evaporation and millet evapotranspiration during the whole growing period of millet in Liudaogou watershed of Shenmu County. The results showed that the Logistic model could simulate the growing processes of millet height and coverage, the correlation coefficients of simulated and measured values reached 0.99. Total precipitation was almost equal to the water consumption of millet, but from heading to filling stage millet suffered water stress. In the whole growing period of millet, about 44% of the total field evapotranspiration was consumed by the soil evaporation. There were significant exponential function relations between leaf area index, soil moisture at in 0-10 cm depth and the ratio of evaporation and evapotranspiration, the correlation coefficients were higher than 0.8. The study can provide theoretical support for rational use of limited water resources and improvement of water use efficiency in rain-fed region of Loess Plateau in Northern Shaanxi.