修剪深度对茶树修剪枝叶生物量及其组分持水特性的影响

摘要

The hydrological function is one of the important ecological contributions of tree litter in a forest.To understand the eco-hydrological effects of litter from bush pruning in tea plantations,the biomass,water retention, and flood-intercepting capacity of the litter were studied in the field as well as in the laboratory with simulation experiments.The results indicated that the various pruning practices produced 1.75 tons to 2.49 tons of litter biomass per hm2 ;and,the water retention of the litter peaked within 2 h after a rainfall.The maximum water holding of the leaves was 106.1 6%,which was greater than that of the leaves-stems mixture,and followed by that of the stems;that of the mixed litter was 121.33% by the moderate pruning,1 13.69% by the severe pruning,and 106.1 6% by the light pruning;the average rate of water absorbed by the leaves was 2.14 g·g-1 ·h-1 ,followed by the mixed litter,and the lowest by the stems;the maximum flood-intercepting rates ranged from 95.12% to 1 10.12% with effective rates of 79.1 9% - 91.91%;when the clippings of leaves and stems were mixed,the capacity was highest with the moderate pruning with an effective intercepting capacity of 2.1 9 t·hm-2 ,followed by the severe pruning,and the lowest with the light pruning.It was concluded that after pruning the potential of a teaplantation to prevent flooding from a heavy downpour was less than that of the forest ecosystem at large.%为了解茶树修剪对修剪枝叶凋落物生物量及其生态水文特性的影响规律,采用田间修剪与室内持水模拟试验相结合的方法,研究不同深度修剪下修剪凋落物的生物量、持水特性及拦蓄能力。结果表明：3种修剪处理下修剪凋落物的生物量为1.75~2.49 t·hm-2,修剪凋落物持水作用主要表现在降雨前期的2 h 内。枝叶混合样的最大持水率表现为：中度修剪(121.33%)>重度修剪(113.69%)>轻度修剪(106.16%)；其中叶组分的平均最大持水率为137.47%；3种修剪处理下凋落物及其组分的最大吸水速率均表现为：叶>混合>枝；其中叶的平均最大吸水速率为2.14 g · g-1· h-1。而枝叶混合组分的对降水的最大拦蓄率为95.12%~110.12%,有效拦蓄率为79.19%~91.91%,其最大持水量、最大拦蓄量及有效拦蓄量均表现为：中度修剪>重度修剪>轻度修剪。其中中度修剪下的单次修剪凋落物的有效拦蓄量为2.19 t·hm-2。研究表明,茶园生态系统凋落物的拦蓄降水能力要小于森林生态系统。