中国南方喀斯特石漠化地区3种经济林土壤呼吸日动态特征

Daily variations of soil respiration among three types of non-wood forest in karst rocky desertification areas, Southern China

喀斯特石漠化作为一个脆弱生态系统,对全球气候变化和碳循环具有重要影响。为阐明中国南方喀斯特石漠化生态治理工程背景下土壤呼吸作用的时空动态变化特征及其影响因素,选取贵州省贞丰县北盘江镇查耳岩村的核桃林Julans regia、花椒林Zanthoxylum bungeamum和关岭县花江镇峡谷村的枇杷林Eriobotrya japonica3种特色经济林作为研究对象,采用英国ADC Bioscientific公司生产的Lcpro+便携式土壤呼吸仪对土壤呼吸进行了监测。结果表明:1)土壤温度能预测土壤呼吸速率变异83%～89%的信息,是影响土壤碳排放量变异的主要因素;2)3种经济林中土壤呼吸的温度敏感性(Q10)有所差异,Q10为4.34～6.40;3)喀斯特石漠化地区冬季土壤的月平均碳排放量达到了63.46 g·m-2;4)土壤呼吸速率的偏离程度变化较大,在-56%～83%之间;5)花椒林在09:00、15:00、21:00,核桃林0:00、11:00,枇杷林在12:00土壤的呼吸速率与日平均值偏离程度较小(<10%),为最佳观测时间;6)各土壤特征因子中,全钾是影响土壤呼吸速率变异的主要因素。

As a fragile ecosystem,karst rocky desertification area has an important impact on global climate change and carbon cycle.In order to elucidate the temporal and spatial variation characteristics of soil respiration and its influencing factors under the background of Ecological Rehabilitation Project of Karst Rocky Desertification in Southern China,by taking three types of non-timber forests including Julans regia forest(in Chaleyan village,Bei Pan Jiang Town,Zhenfeng County,Guizhou),Zanthoxylum bungeamum(same to the former)and Eriobotrya japonica(Canyon Village,Huajiang town,Guanling County,Guizhou)as studied objects,the three forestland soil respiration values were monitored by means of Lcpro+portable soil respirator which is produced by British ADC Bio-scientific Company.The results show that1)Soil temperature can predict83%-89%variation of soil respiration rate,which is the main factor affecting variation of soil carbon emissions.2)The temperature sensibility of soil respiration(Q10)of the three types of non-wood forests were different,ranged from4.34to6.40;3)The monthly average carbon emissions of soil in karst rocky desertification area reached63.46g·m^-2in winter;4)The deviation degree values of soil respiration rate varied greatly from-56%to83%;5)The best observation time points for Z.bungeanum forest were at09:00,15:00,21:00,those for walnut forest at0:00and11:00,and that for loquat forest at12:00.6)Total potassium was the main factor affecting soil respiration rate variation in all soil characteristic factors.