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改变植被类型不仅可使土壤水分利用方式发生变化,而且还能改变一个区域的水分平衡。本项研究旨在确定不同丘陵地牧场的C_3和C_4牧草对土壤含水量的影响。在中部的阿巴拉契亚地区,分别在海拔920m和615m处进行了土壤水分变化的监测。试验小区播种了鸡脚草(C_3)和柳枝稷及狗牙根(C_4)三种牧草。在920m处,鸡脚草的土壤水分消耗量比柳枝稷或狗牙根常常大20~40mm;而在615m处,它们之间不存在显著差异。此外,虽熊C_4的两种草在草冠高度和形状等方面有很大差异,但在920m和615m处柳枝稷和狗牙根之间不存在土壤水分消耗的差异。615m处各种牧草土壤水分消耗量比920m处大,这主要是受土壤性质不同的影响。
Changing vegetation types can not only change the pattern of soil water use, but also change the water balance in a region. This study aimed to determine the effects of C_3 and C_4 herbage on soil water content in different hilly pastures. In the Appalachian region of the Middle, soil moisture changes were monitored at altitudes of 920 m and 615 m, respectively. The test plot sowed three kinds of grasses (C_3) and switchgrass and bermudagrass (C_4). At 920 m, the soil water consumption of the hedgehog was 20 to 40 mm longer than the switchgrass or bermudagrass; at 615 m, there was no significant difference between them. In addition, there was no significant difference in soil water consumption between switchgrass and bermudagrass at 920 m and 615 m, although there was a great difference in grass crown height and shape between the two grasses. At 615m, the soil water consumption of various forage grass was larger than 920m, which was mainly affected by the different soil properties.