贵阳次生林土壤有机碳含量对土壤生物学活性的影响  

Influence of Soil Organic Carbon on Soil Biological Activities Among Secondary Forests of Guiyang City

作　　者：彭艳[1] 李心清[2] 

机构地区：[1]贵州民族学院发展规划处,贵阳550025 [2]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550002

出　　处：《科技导报》2011年第14期33-40,共8页Science & Technology Review

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-306-3);中国科学院创新团队国际合作伙伴计划;国家重点基础研究发展计划(973计划)项目(2006CB403205);贵州民族学院人才科研基金资助项目

摘　　要：次生林是喀斯特森林生态系统的组成部分,未来的森林可能就是次生林。土壤有机碳(SOC)是土壤有机质的重要组成,其含量是土壤肥力的重要指标,对土壤生物学活性有重要影响。为了解次生林土壤有机碳对土壤生物学活性的影响,在贵阳市郊设置灌丛、女贞林、马尾松林3个样点,于2008年6月—2009年5月进行为期1a的采样,并与农田土壤进行对比分析。结果显示,灌丛SOC含量最高,基于SOC/g来看,其含C底物的利用率却最低,土壤生化过程弱,植物和微生物可利用的营养物质较少;女贞林N转化速率较快,林下具有反硝化能力的菌群的酶丰富,气态N流失严重;马尾松林基于每克SOC的土壤有机残体分解的速度快、强度高,微生物活性、土壤酶活性高,土壤生化过程强烈,气态氮流失率最低。总的来说,研究区域土壤SOC含量限制了微生物群落规模,对灌丛土壤酶活性影响较大,SOC含量也间接地影响了微生物体N转化速率和有机物的分解速率,但对反硝化作用的影响不显著;建议在土壤恢复初期优先让草或灌木生长,改善立地条件,之后再选择适宜的树种按照针阔混交模式植树造林。The secondary forest, as an integral part of Karst forest ecosystem, may be the future of a forest. The soil organic carbon is an important part of the soil organic matter and its content has a major impact on soil biological activities and is also an important indicator of the soil fertility. To understand the effects of soil organic carbon on soil biological activities, three sample plots are taken, including a shrub, a Ligustrum lucidum forest and a pine forest and they are compared with the tilled field in the suburbs of Guiyang City during the sampling time （June, 2008-May, 2009）. The data show that the shrub is characterized by low substrate carbon utilization, weak biochemical processes and less available nutrients of plants and microbes based on per gram soil organic carbon, although with the highest soil organic carbon among the sample plots. The Ligustrum lucidum forest is marked by high nitrogen cycle rate, rich in denitrification enzyme and serious gaseous nitrogen loss, while, the pine forest is characterized by high decomposition speed and strength, high soil microbial and enzyme activities, strong soil biochemical processes and low gaseous nitrogen loss based on per gram soil organic carbon. Generaly speaking, the organic carbon content limits the size of soil microbial communities, affects soil enzyme activities in shurbs, influences the microbial nitrogen conversion rate and organic matter decomposition rate indirectly but has no signifcant effects on denitrification in the study area. Therefore, the most appropriate way to the remediation of degraded desertification soil is to allow the natural plant communities to develop in order to improve site conditions in the early stage of the soil remediation and then to select appropriate tree species with the mixed model of coniferous-broadleaved species.

关 键 词：有机碳 生物学活性 反硝化作用 土壤酶活性 

分 类 号：S714[农业科学—林学]