黄土高原沟壑区人工植被类型对土壤水分和碳氮的影响

以黄土高原沟壑区人工建造的典型植被油松、侧柏、刺槐、沙棘、苹果为研究对象，研究分析了不同植被类型对土壤水分含量、土壤碳氮累积等的变化影响。研究表明，旱季刺槐林地表现出了强烈的耗水特征，200cm以下土壤含水量具明显减少趋势。200—300cm处水分含量仅为5．8％～7．1％，而油松林地200cm以下与荒草地含水量基本相一致，土壤水分含量保持在15％左右，侧柏、沙棘、苹果土壤水分利用主要在20-200cm范围内。雨季，天然降雨虽对林地水分含量有所补充，但只表现在0-50cm表层，且各个植被类型间表现不明显；与荒草相比，油松群落土壤有机碳氮提高了9．3％，果园土壤有机碳含量显著降低，而沙棘、侧柏和刺槐群落的土壤有机碳含量虽低于荒草群落，但尚未达到显著水平。

Effects of Artificial Vegetation Types on Soil Moisture, Carbon and Nitrogen in the Hill and Gully Area of the Loess Plateau

Reforestation plays an important role in soil conservation and soil carbon sequestration.Five types of artificial vegetation were selected in the Wangdonggou watershed located in the hill and gully area of the Loess Plateau to understand the influences of artificial vegetation on soil properties.Soil moisture, soil or- ganic C(SOC), and total soil nit rogen were investigated under different types of vegetation.During dry sea- son, there was the intense water consumption characteristic in locust tree forest land and soil water content below the 200 cm depth ranged from 5.8% to 7.1%, showing a decrease wit h depth.Compared to grass- land, Chinese pine forest land had a soil water content of 15% in the same layer.Soil moist ure used for ori- ental arbor-vitae, sea-buckthorn, and apple was mainly distributed between 20 and 200 cm from soil surface.Although natural rainfall had a supplement to the forest land, soil water within 50 cm of soil surface was recharged in rainy season.Compared with grassland, SOC content was increased by 9.3% for Chinese pine and decreased by 40.1% for orchard.SOC contents of sea-buckthorn, oriental arbor-vitae, and locust tree were lower than those on grassland, although not significantly.