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为深入揭示短期放牧对高寒草甸生态系统地表水文过程的影响机理,基于5个放牧强度(A:2.75只羊/hm~2;B:3.64只羊/hm~2;C:4.35只羊/hm~2;D:4.76只羊/hm~2;E:5.20只羊/hm~2)的3a控制放牧试验,对比研究了表层土壤(0—10cm)物理性状、入渗过程、土壤水分特征曲线及持水和供水能力对放牧强度的响应。结果表明:C处理的土壤初始含水量显著高于D、E处理,但各放牧强度的土壤容重和4个孔隙指标无显著变化;放牧改变了土壤入渗过程,随放牧强度增加,B与C处理入渗较好,D与E处理入渗较差;Gardner模型适用于放牧强度的土壤水分特征曲线拟合,相关系数均达极显著水平,且表征土壤持水性能的a值与低中吸力段含水量表明B与C处理的持水能力高于其它处理;100kPa吸力下比水容量显示,A、B和C处理较D与E处理提高了土壤供水能力。总之,合理放牧强度短期内有利于保存高寒草甸土壤含水量,增强土壤导水性和持水能力,保证土壤有效供水,降低高寒草甸生态系统的退化风险。
In order to reveal the mechanism of short-term grazing on the surface hydrological process of alpine meadow ecosystem, based on five grazing intensities (A: 2.75 sheep / hm ~ 2; B: 3.64 sheep / hm ~ 2; C: 4.35 sheep / hm ~ 2; D: 4.76 sheep / hm ~ 2; E:5.20 sheep / hm ~ 2) 3a control grazing experiment, the comparative study of surface soil (0-10cm) physical properties, infiltration process, Curve and Response of Water and Water Supply Ability to Grazing Intensity. The results showed that initial soil moisture content of C treatment was significantly higher than that of D and E treatments, but no significant change was observed in soil bulk density and four pore indexes of each grazing intensity. Grazing changed soil infiltration process. With grazing intensity increasing, B and C The treatment infiltration is better and the infiltration of D and E is worse. The Gardner model is suitable for soil water characteristic curve fitting of grazing intensity with the correlation coefficient reaching extremely significant level, and the value of a and soil water holding capacity The water cut of section B and C shows that the water holding capacity of treatment B and C is higher than that of other treatments. The specific water capacity of 100kPa suction shows that treatments A, B and C are more effective than D and E to improve soil water supply. In short, reasonable grazing intensity in the short term is conducive to preserving alpine meadow soil moisture content, enhancing soil water conductivity and water holding capacity, ensuring soil effective water supply and reducing the risk of degradation of alpine meadow ecosystems.