管理模式对青藏高原南缘亚高山草甸土壤呼吸的影响

Effect of Management Patterns on Soil Respiration of Subalpine Meadow at the Southern Margin of Tibetan Plateau

为探明管理模式对青藏高原南缘亚高山草甸土壤呼吸速率的影响,本研究以迪庆州小中甸镇自由放牧、生长季封育4年、全年封育4年以及封育割草25年的亚高山草甸典型样地为研究对象,开展不同管理模式亚高山草甸土壤呼吸呼吸速率的比较研究,结果显示:(1)管理模式不会改变青藏高原南缘亚高山草甸的土壤呼吸日、季动态变化趋势。土壤呼吸速率在一天中(8:00—18:00)呈先升高后降低的变化趋势,14:00—16:00达到峰值,16:00后呈下降的变化趋势;在植物生长季(6—10月份)的土壤呼吸速率随季节的延长先增加,7月下旬—8月中旬达最峰值,后显著降低(P<0.05)。(2)不同管理模式下青藏高原南缘亚高山草甸土壤呼吸速率生长季平均值的高低顺序为全年封育4年>封育割草25年>生长季封育4年>自由放牧,以全年封育4年和封育割草25年的土壤呼吸速率显著高于生长季封育4年和自由放牧(P<0.05)。本项研究成果不仅可为估算亚高山草甸土壤与大气碳交换量提供科学依据,同时也可为亚高山草甸适宜利用管理策略的制定提供指导。

In order to explore the impact of management patterns on soil respiration rate of subalpine meadow at the southern margin of Tibetan Plateau, the free grazing meadow, growing season fencing meadow （fencing for 4 years）, total fencing meadow （ fencing for 4 years）, and mowing and fencing meadow （ mowing for 25 years） , which locate in Xiao Zhongdian Town, Shangri-La, were selected as research plots. And the soil respiration rates of subalpine meadow under different management patterns were studied. The results showed as follows： （1） the diurnal and seasonal variation tendency of soil respiration rate could not be changed by management patterns. As the time changes from 8 ： 00 a. m to 18：00 p. m, the soil respiration rate of subalpine meadow increased first, the maximum value occurred at 14： 00--16： 00, and then decreased. During the growing season from June to October, the soil respiration rate of subalpine meadow increased first, the maximum value occurred at late July to early August, and then decreased significantly （ P 〈 0.05 ）. （2） The rank of average soil respiration rate of subalpine meadow in different management patterns was total fencing 4 years 〉 mowing and fencing 25 years 〉 growing season fencing 4 years 〉 free grazing, and the soil respiration rates at total fencing and mowing and fencing plots were significantly higher than those at growing season fencing and free grazing plots （P 〈 0. 05 ）. The results of this study can not only provide a scientific basis for esti- mating carbon exchange of subalpine meadow between soil and atmosphere, but also can provide a guidance for constituting appropriate management strategies of subalpine meadow. The results of this study can not only provide a scientific basis for estimating carbon exchange of subalpine meadow between soil and atmosphere, but also can provide a guidance for constituting appropriate management strategies of subalpine meadow.