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经多年田间试验观察,分析渭北旱原裸地和农田土壤水分变化特征,根据土壤水分的年动态,可分为四个不同时期:即相对稳定期、缓慢消耗期、大量损耗期和恢复期。结合不同降水年型和不同作物,茬口及肥力分析其对土壤水分的影响,可以看出不同水文年土壤水分动态有较大差异,其中丰水年和干旱年土壤水分较平水年变化平缓。但土壤水分恢复程度不受作物(一年生),茬口和肥力的影响。根据垂直剖面土壤水分变化特点,依次将其分为三个层次:即活跃层、次活跃层和相对稳定层。丰水年活跃层仅为10cm,且10cm以下均为相对稳定层,干旱年活动层和平水年一致,但次活跃层仅为10cm。从整体情况看,平水年土壤水分变化均较干旱年和丰水年活跃。
After many years of field experiment, we analyzed the characteristics of soil moisture in bare land and farmland in Weibei dry land. According to the annual dynamics of soil moisture, we can divide into four different periods: relative stable period, slow depletion period, large loss period and recovery period . According to different years of precipitation and different crops, stubble and fertility analysis of the impact of soil moisture, we can see that there is a great difference in soil moisture dynamics in different hydrological years, of which the change of soil moisture in flat and wet years is smoother than that in flat water. However, the degree of soil moisture recovery is independent of crop (annual), stubble and fertility. According to the characteristics of soil moisture change in vertical section, it is divided into three levels: active layer, sub-active layer and relatively stable layer. The active layer in Fengshui was only 10cm, and the layers below 10cm were all relatively stable. The active layer in dry year was consistent with that in plain water, but the sub-active layer was only 10cm. From the overall situation, the change of soil moisture in plain water was more active than dry and wet years.