西双版纳橡胶林枯落物的持水性能与截留特征

通过野外调查、浸泡试验和模拟降雨实验,测定了西双版纳地区橡胶林枯落物储量、持水能力和截留降雨特征。结果表明:20和40年生的橡胶林枯落物储量分别为8896和6181 t／hm2,其叶、枝、种子果壳和其他部分生物量所占比例分别为571 ％、102 ％、322 ％、04 ％和704 ％、137 ％、154 ％、05 ％;20年生的橡胶林枯落物最大持水率为18036 ％,高于40年生的值（17459 ％）;枯落物吸水速率与浸泡时间之间关系式为S=ktn,前2 h是枯落物主要持水阶段。模拟降雨条件下,橡胶林枯落物截留量随雨强和枯落物厚度增大而增加;截留率与降雨量呈极显著幂函数关系,但受雨强的影响不显著,在80～480 mm的降雨范围,截留率变化幅度为202 ％～1250 ％,截留能力较弱。

Study on water-holding capability and interception characteristics of litter layers under rubber plantations in Xishuangbanna, southwestern China

Field survey,immersion test and simulated rainfall experiments were engaged in a preliminary study to clarify the hydrological effects of litter layers under rubber plantations in Xishuangbanna,southwestern China.Results showed that the litter reserves of the 20 and 40 years’ rubber plantations were 8.896 t/hm2 and 6.181 t/hm2,the proportions of the litter amount of their components(foliage,twig,seed and nutshell,others) were 57.1 %,10.2 %,32.2 %,0.4 % and 70.4 %,13.7 %,15.4 %,0.5 %,respectively.The maximum water capacity of litter of the 20 years’ rubber plantation was 180.36 % of its dry weight,which of the 40 years’ was 174.59 %.The equation between the water absorption rate of the litter and the immersed time could be S=ktn,and the first two hours was critical for litter to hold water.Under the condition of simulated rainfall,the interception rainfall increases with rainfall intensity and litter thickness.The interception rate existed a significant power function relation to rainfall,but it was hardly influenced by rainfall intensity.Interception rate of litter at the rainfall of 8.0—48.0 mm varied from 2.02 %—12.50 %.Based on these results,the hydrological effects of litter layers under rubber plantations were discussed so that it can provide some useful recommendations for operating them reasonably.