黄土高原土壤水分资源特征

The Characterstics of Soil Moisture Resources on the Loess Plateau

经58县调查,黄土高原土壤水分资源有以下特征:一、土壤持水能力高,其主体质地土壤(轻壤、中壤占80%)的田间持水量一般在19%～22%之间,居于全国中上等水平;二、土壤经常处于低储量水分状态,一般只占到田间持水量的60%～80%和43%～55.9%;三、土壤水分利用率偏低。黄土高原地区,0～5m土层的农田存有剩余有效水为463.16～413.4mm;四、生物利用干层普遍存在,有临时和永久性干层。改善土壤水分条件的措施:1.建立合理的农地、林地、草地配置区;2.建立合理的立体利用土壤水分模式;3.采取相应保墒和耕作措施。

On the basis of the Investigation (?) the soil types it is found that the soil moisture resources have the characteristics as follows.1. the water holding capability of soil is high and the field capacity of the main soils ranges from 19 to 22 percent, being as the middle and higher level;2. soil water storage keeps lower regime, generally about 60%～88% and 43%～56% of the field capacity;3. the use ration of the soil moisture is lower, the surplus available water in the depth of 0～5 m varies from 413.40 to 463.16 mm;4. a dry horizon of the biological utilization commenly exists in the loessial soils, i. e., temporary or permanent dry layer.According to the analysis of soil moisture regime, some measures improving soil water conditions have been suggested in this paper.