祁连山南麓退耕地人工植物群落的枯落物容水性能

对位于祁连山南麓的青海省大通县退耕地人工植物群落的枯落物容水性能进行了研究。该地区从20世纪80年代初期陆续退耕还林的人工植物群落年龄虽只有10~27 a,但其枯落物层厚度已达2.9 cm,相当于天然植物群落(30~200 a)的56.9%;其枯落物容水量平均达4 mm,相当于天然植物群落的35.7%。研究表明退耕地植物群落的林龄越大,植物垂直层数越丰富,则枯落物干物蓄积量和容水率越大,枯落物容水量也越大。在人为去除枯落物层后,其地表径流速度较去除前增加了33%~35%,枯落物层的缓流、滞流作用十分明显。经逐步回归分析,影响植物群落枯落物容水量的因素99.8%的为枯落物干物的蓄积量、林龄、植物层数和枯落物容水率。

Water-holding Capability of Litter of Main Plant Communities in Rehabilitated Lands at Southern Foot of Qilian Mountains

The litter water-holding capability of the artificial plant communities of the rehabilitated land in Datong county of Qinghai province located at the southern foot of Qilian mountains was studied. The ages of the artificial communities of these areas is only 10 - 27 years, however the litter in these vegetation has been as thick as 2. 9 cm, which is 56.9 % of the thickness of natural plant communities of 30 to 200 years old ; the water-holding capability of litter averages 4 mm, which is 35.7 % of that of natural plant communities. The results of study also indicated that the older the plant communities were, the more plentiful the canopy layers were, the larger the amount of litter was and higher the water holding rate of litter was. As an important preventing and obstructing measure, litter layer can reduce the rainfall splash and runoff so effectively that the average runoff velocity has increased by 33 % - 35 % after removing litter layers. The results of gradual regression analysis showed that the factors affecting the water-holding capability of litter layers of were 99.8 % from the volume of litter, age of forest, number of plant layer and water-holding ratio of litter.