黄土丘陵区油松人工林和山杨林林冠对降水的再分配及其对土壤水分的影响

本文分析了人王油松（Pinus tabulaeformis）社和山杨（Populus davidiana）林内的年降水量和林冠的年截留量。得出林内降水量（pi）和林外降水量（p）呈直线正比例关系，人工油松林pi₁=0.928P-0.98；山杨林有叶期pi₂=0.889P-0.442；山杨林无叶期为pi₃=0.985P-0.278。林冠截留量（I）与林外降雨量（p）呈幂函数关系。人工油松林是I₁=0.711p^0.461，山杨林有叶期为I₂=0.521p^0.563。林内降水分布不均，最大处为林内平均降水量的1.34倍，最小处为林内降水量的80%。在雨后短时间内，林内土壤水分也分配不均。

REDISTRIBUTION OF PRECIPITATION BY CANOPIES OF ARTIFICIAL CHINESE PINES AND MOUNTAIN POPLARS AND ITS INFLUENCE ON SOIL MOISTURE IN LOESS HILLY REGION

The annual precipitation and its interception in canopies were measured in stands of Pinus tabulaeformis and Populus davidiana It turned out that the precipitation under the canopies (Pi) and in the field (P) were in linear positive correlation, and it was P_i1=0.928p-0.9 for Pinus tabulaeformis;P_i2=0.889p -0.442 for Populus davidiana in the period with leaves, P_i3=0.985p-0.278 for Populus davidiana without leaves. The interception of precipitation in the canopies(Ⅰ) and precipitation in the field were in power function correlation, and it was I₁=0.711p^0.461 for Pinus tabulaeformis; I₂=0.521p^0.563 for Populus davidiana in the period with leaves. The distribution of precipitation under the canopy was uneven. The maximum observed was equal to 1.34 times of the average precipitation,and the minimum was equal to its 0.8 times,in consequence, the soil moisture in the stands was also unevene during a certain period after rain.