塔里木沙漠公路防护林凋落物的持水特性

Study on Water Holding Capacity of Litters in Shelterbelt along the Tarim Desert Highway

采用野外典型抽样和室内浸水的方法,对4种定植年限不同的塔里木沙漠公路防护林带内凋落物的储量、持水量和吸水速率进行研究。结果表明:①不同定植年限防护林内凋落物储量依次为:13 a林带(42.3 t.hm-2)>6 a林带(39.6 t.hm-2)>10 a林带(39.1 t.hm-2)>7 a林带(16.2 t.hm-2)。②沙漠公路防护林的林下未分解层凋落物持水量的排序为:梭梭>柽柳>沙拐枣;而半分解层凋落物持水量的排序是:柽柳>梭梭>沙拐枣,且防护林内凋落物最大持水量半分解层均大于未分解层。③各林龄不同树种不同分解程度的凋落物持水量与浸水时间之间呈对数关系,最佳拟合关系式为:W=b+alg t,吸水速率与浸水时间之间呈幂函数关系,关系式为:V=ktn,凋落物吸水速率在0～1 h内急剧下降,4 h以后下降平稳,其吸水作用逐渐减小。

In this study,the storage,water holding capacity and water absorption rate of litters in shelterbelts with different ages along the Tarim Desert Highway were studied using the methods of typical sampling and soaking extraction.The results showed that the litter storage in shelterbelts with four different ages was in an order of 13-year-old shelterbelt（42.3 t·hm-2）6-year-old one（39.6 t·hm-2）10-year-old one（39.1 t·hm-2）7-year-old one（16.2 t·hm-2）.The water holding capacity of the undecomposed litters in shelterbelts along the desert highway was in an order of HaloxylonTamarixCalligonum,and that of the semi-decomposed litters was in an order of TamarixHaloxylonCalligonum.The maximum water holding capacity of litters in the semi-decomposed layer was higher than that in the undecomposed layer.There was a logarithmic relationship between water holding capacity of litters with different decomposition degrees and watering time,and the optimal fitting relation equation was W=b＋alg t,but a power function relationship between water absorption rate and watering time,and the formula was V=ktn.The water absorption rate was decreased sharply within the first one hour,and reduced stably after 4 hours.Water sorption of litters was decreased gradually.