划破草皮对祁连山不同地形高寒矮嵩草草甸土壤呼吸特征的影响  

Effects of sward cleavage treatment on soil respiration and its influencing factors under different terrain in alpine Kobresia humilis Meadow

作　　者：李小龙[1] 曹文侠[1] 张晓燕[1] 李文[1] 徐长林[1] 师尚礼[1] LI Xiao-Long;CAO Wen-Xia;ZHANG Xiao-Yan;LI Wen;XU Chang-Lin;SHI Shang-Li(College of Pratacultural Science,Gansu Agricultural University/Key Laboratory of Grassland Ecosystem,Ministry of Education/Pratacultural Engineering Laboratory of Gansu Province/Sino-U.S.Centers for Grazingland Ecosystem Sustainability,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室,中-美草地畜牧业可持续发展研究中心,甘肃兰州730070

出　　处：《草原与草坪》2020年第2期30-38,共9页Grassland and Turf

基　　金：现代农业产业技术体系(CARS-34),甘肃省农牧厅“退牧还草科技支撑项目”和“青藏高原打草场建设项目”资助。

摘　　要：以青藏高原东北缘祁连山高寒矮嵩草草甸为对象,用土壤呼吸测量仪分别进行了平地和缓坡地两种地形草甸经划破改良后的土壤呼吸排放速率测定。结果表明:经划破处理的高寒草甸土壤呼吸排放速率呈明显的季节动态,最大值出现在7月。土壤呼吸排放速率与地表温度、5 cm处土壤温度均呈指数正相关关系,与土壤含水量具有拟合度较高的二次多项式相关性,与地上、地下生物量存在正相关关系。土壤呼吸温度敏感性指数Q10显示,划破干扰均增加了两种地形地表温度的Q10值,而5 cm土壤温度仅增加了缓坡地的Q10值。通过随机森林变量重要性评估可知,影响该区域平地土壤呼吸的主导因素为土壤含水量,影响缓坡地土壤呼吸的主导因素为5 cm处土壤温度。因此,在应用划破草皮改良技术时应充分考虑制约条件,因地制宜,才能真正达到改良草地的目的。In this study,the soil respiration emission rate of alpine Kobresia humilis meadow after the sward cleavage in Qilian Mountains on the eastern edge of the Qinghai-Tibet Plateau was measured by soil respiration measurement instrument(LI-8100A,LI-COR,Lincoln,USA)on flat and gentle sloping land respectively.The results showed that soil respiration emission rate manifested obvious seasonal dynamics and reached the greatest peak in July after the sward cleavage.The soil respiration emission rate was positively correlated with the surface temperature and the soil temperature at 5 cm underground department,which had a high degree of quadratic polynomial correlation with the soil water content,and was positively correlated with the aboveground and underground biomass.The soil respiration temperature sensitivity index(Q10)showed that the cleavage interference has increased the Q10 value of the surface temperature of the two terrains,but only increased the Q10 to soil temperature at 5 cm underground department in gentle sloping land.According to the importance assessment of random forest variables,the dominant factor affecting soil respiration in flat land was soil water content and in gentle slope was soil temperature at 5 cm underground department.Consequently,in order to truly achieve the purpose of improving grassland,we should consider fully the constraints and suitability to local conditions when applying the sward cleavage.

关 键 词：高寒草甸 划破草皮 不同地形 土壤呼吸 随机森林 土壤温度 土壤水分 

分 类 号：S812[农业科学—草业科学] S152.4[农业科学—畜牧学]