陇东黄土高原中沟小流域不同植被措施土壤水分差异分析
张立俞1, 邸 利1, 任艺彬2, 黄海霞3, 倪 帆1, 吴贤忠4, 王安民5, 汝海丽5, 刘俊俊6

(1.甘肃农业大学 资源与环境学院, 兰州 730070; 2.陇东学院 农林科技学院, 甘肃 庆阳 745000; 3.甘肃农业大学 林学院, 兰州 730070; 4.兰州市城市学院, 兰州 730070; 5.平凉市水土保持科学研究所, 甘肃 平凉 744000; 6.泾川县自然资源局, 甘肃 泾川 744300)

土壤水分; 林分密度; 林地; 草地; 陇东黄土高原

Difference in Soil Water in Zhonggou Small Watershed with Different Vegetation Measures in Loess Plateau of East Gansu
ZHANG Liyu1, DI Li1, REN Yibin2, HUANG Haixia3, NI Fan1, WU Xianzhong4, WANG Anmin5, RU Haili5, LIU Junjun6

(1.College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, China;2.College of Agriculture &Forestry, Longdong University, Qingyang, Gansu 745000, China;3.College of Forestry, Gansu Agricultural University, Lanzhou 730070, China;4.Lanzhou City University, Lanzhou 730070, China;5.Pingliang Water and Soil Conservation Science Institute, Pingliang, Gansu 744000, China;6.Jingchuan County Natural Resources Bureau, Jingchuan, Gansu 744300, China)

soil moisture; stand density; forestland; grassland; Loess Plateau of east Gansu

备注

为了分析林草地土壤水分含量随土壤剖面深度和时间的变化及林分密度对土壤含水量的影响,以陇东黄土高原中沟小流域林地和草地以及不同林分密度的刺槐林地为研究对象,从2018年4月—10月,对0—120 cm土层的土壤含水量进行了测定。结果表明:(1)在近地表(0—60 cm),不同密度的林地和不同地形部位的林草地多为随土层深度的增加土壤含水量下降,表层土壤含水量变异系数大于深层,并在0—60 cm范围内变幅最大。(2)不同林分密度刺槐林土壤水分含量随时间和土层深度的变化趋势基本一致:低密度林分>中密度林分>高密度林分; 但中、低密度刺槐林土壤水分在0—60 cm范围内差异很小,并在7—8月份2个密度等级林地的含水量非常接近,建议该区域造林密度选择2 000～4 000株/hm2的中密度。(3)不同地貌部位林地和草地土壤含水量随着土层深度的变化不一,塬面表现为林地>草地; 梁坡表现为0—40 cm土壤范围内林地>草地,40 cm以下二者差异很小,草地略高于林地; 沟台表现为0—20 cm土壤范围内林地>草地,20 cm以下草地>林地。故陇东黄土高原塬面与梁坡适宜种树,沟台则适合种草。
Taking the forestland and grassland in the Zhonggou small watershed in the Loess Plateau of east Gansu and the Robinia pseudoacacia forest land with different stand densities as the research objects, the soil water content of the 0—120 cm soil layer was measured from April to October 2018 to analyze the change of soil moisture content with soil profile depth and time and the effect of forest density on soil moisture content. The results showed that:(1)the soil water content all decreased with the increase of the soil depth in forestland with different densities and the forest and grassland at different topography position, and the coefficient of variation of soil water content in the surface was greater than that in the deep layer, with the largest variation in the layer of 0—60 cm and the active layer of soil moisture became shallow;(2)the change trend of soil moisture content of Robinia pseudoacacia forests with different densities over time and soil depth was basically the same; the soil moisture decreased in the order: low-density stands>medium-density stands>high-density stands, the soil moisture difference in the layer 0—60 cm between the medium and low density level was very small, and the water content of stands at the two density grades in July and August was very close; it is recommended to choose planting density at 2 000～4 000 plants/hm2 in this area;(3)the water content of the forest and grassland at different landforms varied with soil depth, it was higher in woodland than grassland at tableland surface; in ridge slope, it was higher in forestland than grassland within 0—40 cm soil layer, while the difference between the two below 40 cm was very small, soil moisture in grassland was slightly higher than the forest land, it was higher in woodland than grassland within 0—20 cm soil layer in gully platform, while it was higher in grassland woodland below 20 cm. Therefore, the tableland surface and ridge slope in the Loess Plateau of east Gansu are suitable for planting trees, and gully platform is suitable for planting grass.