第四纪红色粘土侵蚀土壤水分特性研究

Research on humitity characteristics for laterite soil of quarternary period subject to erosion

水土流失严重的第四纪红色粘土区,夏季因高温少雨使水土保持植物措施难以见效。为了揭示红色粘土的持水特性和水分动态变化规律,对不同地形部位、不同深度的侵蚀土壤,进行了5～11月份的定点观测和持水特性的研究。结果表明:夏季,表层土壤(0～10cm)都有不同程度的干旱,坡上部裸露红色粘土尤为严重;秋季,坡中部10～30cm土层的含水量高于30～60cm的含水量;雨季,侵蚀沟底部沉积物的含水量明显地高于田间持水量;对于有效水含量,侵蚀沟底部较高,而坡上部粘土较低。因此提出:改善土壤结构,增加土壤渗透能力,促进深层贮水和选择深根性植物等措施。

It is difficult to establish vegetation cover in the region of laterite of quarternary period suffering from severe erosion, because of high temperature and less precipitation in summer. In order to find out rules of the humility characteristics and their dynamic varience,the author carried out observation and study of humutity characteristics in different depths of top soil as well as different topographic location. The work shows that the top soil suffers from drought, especially the exoposed bare laterite, in summer; humility in depth of 0 -10cm in middle of slopes is higher than one in depth of 30 - 60cm in autumn.; humility of deposi -tion on the boltom of gullies much higher than Of the field during rainning season;effective humility of such laterite is higher on bottom of gullies and lower on upper part of slopes . Therefore the choice should be made on the deeprooting plants that is very effective to improve structure of soil,increase infiltration and keep water in depth of soil.