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黄土高原山坡上的复合农林业是一种普遍存在的景色,在这里土壤的水分是植物生长和发展的限制因素。文中研究了三种类型复合农林业边界(林-牧地、林-耕地和防护林-耕地)下水分的时空特性。研究结果表明,从土地表面到110cm处土壤的水分含量随着土壤深度的增加而减少。在雨季(7-9月)、干旱季(5-6月)和春季(3-4月),土壤的水分含量在三种边界下变化非常显著。在三种边界类型的不同土壤层下,土壤水分的水平分布呈现出线性、波形、勺形或是“W”形不同的形式。通过方差分析和多重比较估计除了不同边界类型下土壤水分影响域(DEI)。在干旱季节,在0-10cm的土壤层的DEI为0.4H(H为平均树高),该数据从牧地或耕地下的0.2H到林-牧地、林-耕地下的0.2H和防护林-耕地下0.7H(从耕地的0.2H到防护林的0.5H)。在雨季,在0-110cm土壤深度三种边界下的DEI为0.7H。研究结果表明,特别在黄土高原的恢复退化土地区域为了保持土壤的水分在土地管理上复合农林业类型应该谨慎选取。
The agroforestry on the hillside of the Loess Plateau is a ubiquitous landscape where soil moisture is a limiting factor for plant growth and development. In this paper, the spatio-temporal characteristics of water under the three types of agroforestry boundaries (forest-grazing land, forest-cropland and shelterbelts-farmland) were studied. The results show that the soil moisture content from the surface of the soil to 110 cm decreases with the increase of soil depth. In the rainy season (July-September), the dry season (May-June) and the spring (March-April), the moisture content of the soil changed significantly under the three kinds of boundaries. Under the different soil layers of the three boundary types, the horizontal distribution of soil moisture showed a linear, wave shape, spoon shape or “W” shape. An analysis of variance and multiple comparisons were performed except for the Soil Moisture Impact Area (DEI) under different boundary types. During the dry season, the DEI in the 0-10 cm soil layer was 0.4 H (H is the mean tree height), ranging from 0.2 H in grazing land or cultivated land to forest-grazing land, 0.2 H in forest-cropland and shelterbelts - 0.7H under arable land (0.2H from cultivated land to 0.5H from shelterbelts). In the rainy season, the DEI was 0.7 H at the three boundary depths 0-110 cm. The results show that, especially in the rehabilitation of degraded land area in the Loess Plateau in order to maintain soil moisture in the land management of the agroforestry type should be carefully selected.