红壤地区典型农田土壤水力学特性及土壤水库容研究

The Hydraulic Characteristics and Soil Reservoir of Typical Farmland in Red Soil Region

针对红壤地区普遍存在的季节性干旱问题,研究了红壤的水力学特性及土壤库容状况,结果如下:红壤旱地土壤各层的有效水含量变化不大,变化区间为61.00gkg-1～73.77gkg-1,作物可利用的有效水区间较小,不利于作物生长;水田中土壤剖面有效水含量变化明显,变化区间为75.27gkg-1～170.80gkg-1,其中表层和犁底层的有效水含量远大于其它各层次。土壤的饱和含水量主要受容重的影响,粘粒含量主要影响高吸力下的水田土壤含水量。旱地红壤表层总库容和死水库容较高,有效水库容较低,为17.71mm;水田土壤表层死水库容较小,有效水库较高,达到30.74mm。红壤季节性干旱的主要原因是土壤本身理化性质导致的有效水含量较低,难以被作物吸收利用。

Soil water content is an essential factor that can affect crop growth.In red soil region of China,the seasonal water shortage should be a mainly problem to agricultural development.Hydraulic characteristics and soil reservoir of red soil were studied in this paper to find out the reason of seasonal water shortage.The results were as follows：there were no obvious differences of available water content between different layers in soil profile of upland red soil,which variation range was from 61.00 to 73.77 g kg-1.In paddy field,variations of available water content,from 75.27 to 170.80 g kg-1,between different layers were.Soil saturated water content was mainly influenced by soil bulk density.The soil water content was determined by soil clay content in the high pressure situation in paddy field.The total soil reservoir and the unavailable soil reservoir were relatively high in upland red soil,but the available soil reservoir was only 17.71 mm.In paddy field,the unavailable soil reservoir was lower,lead to the available soil reservoir,which value was 30.74 mm,higher than it in upland red soil.The result has shown that the lower available soil reservoir caused by soil physical and chemical properties could be a very important factor to seasonal water shortage in red soil region.