牧压梯度下高寒草甸实际蒸散量及植物生产水分有效利用率的研究

发布时间：2018-03-21 01:09

本文选题：牧压梯度　切入点：高寒草甸　出处：《生态环境学报》2017年09期 　论文类型：期刊论文

【摘要】：以青海海北高寒草甸为研究对象,分析了禁牧(对照,CK)、轻度放牧(light grazing,LG)、中度放牧(moderate grazing,MG)、重度放牧(heavy grazing,HG)试验地土壤贮水量和利用水量平衡法计算的植被实际蒸散量动态变化,并对不同牧压梯度下高寒草甸的水分有效利用率进行了比较。结果表明,牧压梯度下土壤贮水量在生长季的变化特征基本一致,表现为5月、6月高,7月低,8月以后缓慢升高。5月8日到9月28日0~50 cm土层平均土壤贮水量为CKHGLGMG,分别为(222.82±7.07),(199.71±4.52),(189.00±4.37)和(187.69±3.93)mm,表明放牧使土壤贮水量减小,统计分析表明,禁牧与放牧地之间贮水量差异达极显著水平(P0.01)。不同牧压梯度上高寒草甸植被实际蒸散量在生长季的变化特征基本一致,表现出5月低,6月开始升高,7月蒸散量达最大,以后逐步下降;整个生长季CK、HG蒸散量较高,LG、MG蒸散量较低,分别为(389.37±3.39)、(355.74±5.54)、(350.17±8.6)3和(346.15±1.31)mm。从土壤水分亏缺来看,重牧不利于水源涵养,但禁牧亦影响水源涵养功能的提高,只有适度放牧有利于水源涵养。植被实际蒸散量与降水量呈极显著正相关关系。高寒草甸植被地上地下净初级生产力在生长季的水分有效利用率表现为LG、MG较高,HG较低,CK的水分有效利用率最低,分别为0.55%、0.56%、0.50%和0.37%,说明适度放牧能够提高植被水分有效利用率,而禁牧显著降低植被水分有效利用率。
[Abstract]:Taking the alpine meadow in Haibei Qinghai as the research object, the dynamic changes of soil water storage and actual evapotranspiration calculated by the method of balance method of soil water storage and utilization water were analyzed in the experimental plots of forbidding grazing (CK, light grazingl, moderate grazing moderate grazingln MGG, heavy heavy grazingling HG). The results showed that the variation characteristics of soil water storage in growing season were basically the same under different gradients of grazing pressure. From May 8th to September 28th, the average soil water storage of 50cm soil layer was CKHGLGMGGG, which was 199.71 卤4.52mg, and 187.69 卤3.93mm, respectively, which indicated that grazing reduced the soil water storage, statistical analysis showed that the average soil water storage was higher in May, greater in May, and lower in May, and increased slowly after May, and the average soil water storage was CKHGLGMGG from May 8th to September 28th, which were respectively 199.71 卤4.52mb and 187.69 卤3.93mm, respectively, which indicated that grazing decreased the soil water storage. The difference of water storage between forbidden grazing land and grazing land reached a very significant level (P 0.01). The variation characteristics of actual evapotranspiration of alpine meadow vegetation on different gradients of grazing pressure were basically the same in the growing season, showing low in May, rising in June, and maximum evapotranspiration in July. During the whole growing season, the evapotranspiration of CKN HG was higher than that of LGMG, which was 389.37 卤3.39, 355.74 卤5.54, 350.17 卤8.6mm. and 346.15 卤1.31mm. from the point of soil water deficit, heavy grazing was not good for water conservation, but forbidding grazing also affected the improvement of water conservation function. Only moderate grazing was beneficial to water conservation, and the actual evapotranspiration of vegetation was positively correlated with precipitation. The effective water use efficiency of net primary productivity of vegetation above ground in alpine meadow was higher than that of LGG in growing season. The water use efficiency of CK was the lowest, 0.55 0.56% and 0.37%, respectively, indicating that moderate grazing can increase the effective utilization ratio of vegetation water, while forbidding grazing can significantly reduce the effective utilization rate of vegetation water.
【作者单位】：中国科学院西北高原生物研究所;中国科学院大学;中国科学院高原生物适应与进化重点实验室;
【基金】：国家重点研发计划项目(2016YFC0501802) 青海省国际合作项目(2015-HZ-801) 青海省自然基金项目(2016-ZJ-943Q)
【分类号】：S812

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