梯田玉米土壤水分动态研究

依据田间试验资料，对梯田玉米土壤水分动态特征进行了研究。并以谷子和休闲地作为对比，对不同植被覆盖条件下的梯田土壤水分差异进行了探讨。结果表明：（1）雨季降水对玉米地土壤水分的补给起着重要的作用，其土壤贮水量动态与年内的降雨周期相吻合；（2）不同植被覆盖条件对梯田土壤水分状况影响较大，玉米、谷子全生育期的农田蒸散量分别为502．9mm和473．9mm，同期对照休闲地的蒸散量仅为414．1mm；（3）玉米全生育期ET／E0（农田蒸散量／同期水面蒸发量）的比值为0．77，并且在拔节期和抽雄期都大于1，而谷子全生育期该值为0．69。

Soil Moisture''s Dynamics in Maize Field of Trrace in Loess Plateau

Based on the field experiments,soil moisture dynamics of a maize field was studied.Impacts of different land covers on soil moisture were conducted in comparison with soil moisture of a millet field and fallow field.The results showed that precipitation in the raining season played an important role in supplying soil water in the maize field and the soil moisture's dynamic period was coincided with the raining season;different land covers had strong effect on the soil moisture,and the evapotranspiration amounts of maize and millet plots were 502.9 mm and 473.9 mm,respectively,but the fallow land,only 414.1 mm;the ET/E_0 ratio of the maize field(evapotransipration/ water surface evaporation) in the entire growing period was 0.77,however,its ratios was greater than 1.00 in the jointing stage and the following stage.The ratio for the whole growing period was 0.69 on the millet field.