祁连山天涝池流域不同植被群落枯落物持水能力及时间动态变化

Study on the water-holding capacity of litter of different vegetation types in Tianluochi catchment of Qilian Mountains

利用根钻采样法和室内浸泡法对祁连山天涝池流域4种优势植被群落(青海云杉林、祁连圆柏林、金露梅灌丛和亚高山草地)枯落物的持水能力和时间动态变化进行研究,结果表明,不同植被群落枯落物的蓄存量由大到小依次为青海云杉林(34.57 t/hm2)、祁连圆柏林(28.01 t/hm2)、金露梅灌丛(20.41 t/hm2)、亚高山草地(3.27 t/hm2);不同植被群落枯落物的最大持水率由大到小依次为金露梅灌丛(326.63%)、青海云杉林(267.82%)、祁连圆柏林(175.23%)、亚高山草地(149.56%);不同植被群落枯落物的有效拦蓄量由大到小依次为青海云杉林(67.34 t/hm2)、金露梅灌丛(50.70 t/hm2)、祁连圆柏林(36.07 t/hm2)、亚高山草地(3.14 t/hm2);青海云杉林下不同覆盖类型枯落物的持水能力表现为苔藓+枯落物层>枯落物层>草+枯落物层;枯落物持水量与浸泡时间存在明显的对数关系,枯落物吸水速率与浸泡时间之间存在较好的幂函数关系.

In order to study the water holding capacity and its temporal variation of litter,four kinds of vegetation such as Picea crassifolia forest,Sabian przewalskii forest,Potentilla fruticosa shrub and subalpine meadow in the Tianluochi catchment of Qilian Mountains were selected as our study objects.By soaking collected litter samples,litter stocks,their maximum water holding capacity and effective waterretaining amounts of litter were measured.The results showed that the order of litter storage of the four vegetation types from big to small was P.crassifolia(34.57 t/hm^2),S.przewalskii(28.01 t/hm^2),P.fruticosa(20.41 t/hm^2)and subalpine meadow(3.27 t/hm^2);the sequence of maximum water holding capacity of litter for them from big to small was P.fruticosa(326.63%),P.crassifolia(267.82%),S.przewalskii(175.23%)and subalpine meadow(149.56%);the effective interception rates of litter from big to small in the order were P.crassifolia(67.34 t/hm^2)>S.przewalskii(50.70 t/hm^2)>P.fruticosa(36.07 t/hm^2)>subalpine meadow(3.14 t/hm^2).The water-holding capacity of litter under different covering types in the P.crassifolia forest was shown as moss+litter layer>litter>grass+litter layer.There was an obvious the logarithmic relationship between litter water holding capacity and soaking time,and there was a significant power function relationship between the litter water absorption rate and soaking time.