荒漠草原灌丛转变土壤有机碳矿化及其对降水梯度的响应  

Soil organic carbon mineralization and its response to precipitation gradients during anthropogenic shrub encroachment in desert steppe

作　　者：赵晓钰 陈彦硕 李志刚[1] 王红梅[1,2,3] 张振杰 李志丽[1] 苏荣霞 赵亚楠 ZHAO Xiaoyu;CHEN Yanshuo;LI Zhigang;WANG Hongmei;ZHANG Zhenjie;LI Zhili;SU Rongxia;ZHAO Yanan(College of Forestry and Prataculture,Ningxia University,Yinchuan 750021,China;Ningxia Grassland and Animal Husbandry Engineering Technology Research Center,Yinchuan 750021,China;Key Cultivation Laboratory of Ecosystem Restoration and Reconstruction,Ministry of Education,Yinchuan 750021,China)

机构地区：[1]宁夏大学林业与草业学院,银川750021 [2]宁夏草牧业工程技术研究中心,银川750021 [3]西北退化生态系统恢复与重建教育部重点培育实验室,银川750021

出　　处：《生态学报》2024年第15期6630-6641,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(32260348,31860677);宁夏高等学校一流学科建设项目(NXYLXK2017A01)。

摘　　要：为探究灌丛引入对荒漠草原土壤有机碳稳定性的影响,选取近40年的典型草原-灌丛镶嵌体(荒漠草地,草地边缘,灌丛边缘、灌丛地)为研究对象,开展荒漠草原向灌丛人为转变过程野外原位观测结合室内培养的土壤有机碳矿化及其对降水变化(+40%、+20%、CK、-20%、-40%)的响应特征研究,主要结果如下:荒漠草原人为灌丛转变的过程中土壤有机碳、全氮和全磷含量显著降低;土壤有机碳累积矿化量、碳矿化速率、碳矿化及微生物代谢熵均随着转变过程呈上升趋势,且灌丛地较荒漠草地分别增加了26.6%、27%、25.8%和26.8%;土壤潜在可矿化有机碳量随转变波动上升,灌丛地显著高出荒漠草地31.55%;转变样地在不同降水梯度下土壤有机碳矿化速率呈下降趋势,但灌丛地、灌丛边缘土壤有机碳矿化始终高于荒漠草地和草地边缘地,其中灌丛地与灌丛边缘有机碳矿化对降水降低响应更加敏感和积极,结果表明荒漠草原向灌丛转变过程增强了土壤有机碳微生物矿化的同时,还提高了其应对干旱的能力,这种能力或许是以更高的微生物代谢熵和二氧化碳通量为代价。To explore the impact of the anthropogenic transition from grassland to shrubland on soil organic carbon stability,a nearly 40 years typical grassland-shrubland mosaic(desert grassland,grassland edge,shrubland edge,shrubland)was selected to investigate soil organic carbon mineralization and its response characteristics of the precipitation(+40%,+20%,CK,-20%,-40%)by field in-situ observations combined with indoor incubation in the transition process.The main results were that soil organic carbon,total nitrogen and total phosphorus contents were significantly reduced and the cumulative soil organic carbon mineralization,the mineralization rate of soil organic carbon,carbon mineralization,and microbial metabolic entropy all showed an increasing trend with the transition process.It increased by 26.6%,27%,25.8%,and 26.8% in shrubland compared to desert grassland.The potentially mineralized carbon increased with transition fluctuations and was significantly higher in shrubland than in desert grassland by 31.55%.Under different precipitation gradients,the cumulative soil organic carbon mineralization in each transition site tended to increase with incubation time,and the mineralization rate of soil organic carbon tended to decrease.However,soil organic carbon mineralization was higher in shrubland and shrubland edge than in desert grassland and grassland edge.Soil organic carbon mineralization in shrubland and its edge was more sensitive and cheerful in response to reduced precipitation.In a conclusion,microbial mineralization of soil organic carbon was accelerated,and its capability of responding to drought was enhanced during these vegetation shifts.The results suggested that the transition process enhanced the microbial mineralization of soil organic carbon and its capacity to cope with drought,a capacity that perhaps came at the cost of higher microbial metabolic entropy and CO2 fluxes.

关 键 词：荒漠草原 人为灌丛化 土壤碳矿化 降水梯度 

分 类 号：S812.2[农业科学—草业科学]