不同放牧强度下祁连山南麓高寒草甸草毡层及其土壤水分特征  

Characteristics of the grass felt layer and soil moisture in alpine meadows at the southern foot of the Qilian Mountains under different grazing intensities

作　　者：何琦 王军邦[3] 李慧婷 陈宇鹏 樊博 周华坤[2] 张秀娟[1] 杨永胜[2,6] HE Qi;WANG Junbang;LI Huiting;CHEN Yupeng;FAN Bo;ZHOU Huakun;ZHANG Xiujuan;YANG Yongsheng(College of Horticulture and Gardening,Yangtze University,Jingzhou 434025,Hubei,China;Qinghai Key Laboratory of Restoration Ecology in Cold Regions/Key Laboratory of Adaptation and Evolution of Plateau Biota,Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,Qinghai,China;Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China;Beishan Forest Farm in Xining City,Xining 810003,Qinghai,China;College of Eco-Environmental Engineering,Qinghai University,Xining 810016,Qinghai,China;Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem,Xining 810001,Qinghai,China)

机构地区：[1]长江大学园艺园林学院,湖北荆州434025 [2]中国科学院西北高原生物研究所/青海省寒区恢复生态学重点实验室/国科学院高原生物适应与进化重点实验室,青海西宁810001 [3]中国科学院地理科学与资源研究所/生态系统网络观测与模拟重点实验室,北京100101 [4]西宁市北山林场,青海西宁810003 [5]青海大学生态环境工程学院,青海西宁810016 [6]青海海北高寒草地生态系统国家野外科学观测研究站,青海西宁810001

出　　处：《草业科学》2023年第11期2740-2750,共11页Pratacultural Science

基　　金：国家自然基金青年项目(32001149);国家自然基金联合项目(U20A2006);国家自然基金面上项目(31971507);青海省应用基础研究项目(2022-ZJ-716);中国科学院青海省人民政府三江源国家公园联合研究专项(LHZX-2020-02-02、LHZX-2020-10-1);中国科学院青年创新促进会(2022436)。

摘　　要：为探讨放牧强度对高寒草甸草毡层及其土壤水分特征的影响,本研究分析了不同放牧强度[轻度(4.5羊单位·hm^(-2))、中度(7.5羊单位·hm^(-2))、重度(15羊单位·hm^(-2))和极重度(30羊单位·hm^(-2))]对祁连山南麓高寒草甸草毡厚度、根土比、硬度、抗剪强度、容重、孔隙度、饱和导水率和持水能力的影响。结果表明:1)随着放牧强度的增加,植物群落结构从轻度至重度放牧较稳定,至极重度放牧,禾本类植物重要值占比显著下降(P<0.05),莎草类和杂草类植物重要值显著增加。2)草毡层厚度和根土比均随放牧强度增加呈上升趋势,在极重度放牧达到最大。土壤硬度无显著变化(P>0.05)。土壤抗剪强度呈先增加后稳定的趋势,中度放牧样地最大;土壤容重随放牧强度增加呈先减少后增加趋势,重度放牧样地最低,极重度放牧样地显著增加。总孔隙度、毛管孔隙度随放牧强度增加呈先上升后降低趋势,在重度放牧样地达到最大,至极重度放牧,较重度放牧样地显著降低。3)最大持水量、毛管持水量、田间持水量及饱和导水率随放牧强度增加呈先升高后降低趋势,在重度放牧时达到最大,至极重度放牧均下降。4)草毡层厚度与莎草类重要值占比、根土比、土壤抗剪强度、硬度、最大持水量、毛管持水量和田间持水量均显著正相关;容重与草毡层厚度、根土比及各项水分特征指标均显著负相关。冗余分析结果表明,土壤容重和抗剪强度是影响草毡层水分特征的最显著因子。综上,保持一定草毡层厚度且连续的草毡层不但可以在一定程度上保证持水功能平衡,还可以缓冲外界因素对植物群落与土壤结构的损伤,是高寒草甸合理利用和保护的关键所在。To investigate the effects of grazing intensity on the alpine meadow felt layer and its soil moisture characteristics,this study was conducted to analyze the effects of different grazing intensities(light,medium,heavy,and severe)on the thickness,root-to-soil ratio,hardness,shear strength,bulk weight,porosity,saturated hydraulic conductivity,and waterholding capacity of the alpine meadow felt layer at the southern foot of the Qilian Mountains.The results showed that:1)with the increase in grazing intensity,the plant community structure was first stable and then significantly changed.The importance values of grasses,sedges and weeds were stable,from light to heavy grazing.Compared with heavy grazing,the importance value of gramineous plants in extremely heavy grazing increased significantly to 3.95%,and the importance values of sedges and weeds increased to 11.76% and 84.29%,respectively.2)The thickness of the grass carpet layer and root-to-soil ratio both tended to increase with grazing intensity,reaching a maximum at very heavy grazing(6.78 cm,2.55%,respectively),both of which increased significantly compared with light grazing by 212.44%,and 212.50%,respectively.Soil hardness did not change significantly with increasing grazing intensity and remained stable at 18.95 kg·cm^(-2).Soil shear strength tended to increase first and then stabilize,with a maximum value of 2 kg·cm^(-2) in the medium grazing sample.Soil bulk density increased first and then stabilized with the increase in grazing intensity,and significantly decreased to 0.59 g·cm^(-3) in the heavy grazing plot.The bulk density of the felt layer in the extremely heavy grazing plot was 41.54% higher than that in the heavy grazing plot.The total porosity and capillary porosity tended to increase and then decrease with grazing intensity.3)The maximum water holding capacity,capillary water-holding capacity,field water-holding capacity,and saturated hydraulic conductivity tended to increase and then decrease with increasing grazing intensity.4)There was a sig

关 键 词：高寒草甸 放牧强度 草毡层 祁连山南麓 土壤容重 土壤持水量 土壤导水率 

分 类 号：S812.2[农业科学—草业科学]