CO2倍增对稻田土壤碳氮水解酶活性的影响  

Effects of doubled concentration of CO_2 on soil hydrolase activities related to turnover of soil C and N in a rice-cropping system

作　　者：李奕霏 肖谋良[2] 袁红朝[2] 祝贞科[2] 王久荣[2] 李科林 葛体达[2] 吴金水[2] LI Yi-fei;XIAO Mou-liang;YUAN Hong-chao;ZHU Zhen-ke;WANG Jiu-rong;LI Ke-lin;GE Ti-da;WU Jinshui(College of Environmental Science and Engineering,Central South University of Forestry and Technology,Changsha 410128,China;Key Laboratory of Subtropical Agriculture Ecology,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China)

机构地区：[1]中南林业科技大学环境科学与工程学院,湖南长沙410004 [2]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,湖南长沙410125

出　　处：《中国环境科学》2018年第9期3474-3480,共7页China Environmental Science

基　　金：国家自然科学基金资助项目(41501321);湖南省自然科学基金资助项目(2016JJ3132);政府间国际科技创新合作重点专项(S2016G0053)。

摘　　要：为了探究CO_2倍增对土壤微生物生物量和酶活性的影响,选择亚热带区多年种植水稻的典型红壤为研究对象,对不同水稻生育期下土壤微生物生物量碳氮及其土壤碳氮转化关键酶活性:β-葡糖苷酶(β-Glu)、木聚糖酶(Xyl)和几丁质酶(N-Ac)进行了研究.结果表明:相比于常规CO_2浓度(400×10^(-6)),CO_2倍增(800×10^(-6))促进了水稻生物量及土壤微生物生物量碳氮含量,且土壤微生物生物量碳氮受水稻生育期显著影响(P<0.05),在水稻孕穗期时土壤微生物生物量碳氮均达到最大值.总体上,CO_2倍增促进了土壤中β-Glu酶、Xyl酶、N-Ac酶的活性,且三种酶的活性随水稻生育期变化的趋势一致,先递增(在孕穗期的酶活性最大),随后在成熟期下降.在相同生育期和CO_2浓度下酶活性大小为:β-Glu>N-Ac>Xyl.多变量方差分析表明,CO_2浓度和生育期显著影响了水稻植株生物量、土壤微生物生物量碳氮和酶活性,且土壤微生物生物量碳(SMBC)和酶活性对CO_2浓度和生育期的交互作用产生了显著的响应;而且相关性分析表明,SMBC与土壤β-Glu酶、N-Ac酶、Xyl酶活性之间均有显著的正相关.总体而言,CO_2升高可促进水稻生长,增加土壤微生物量和土壤酶活性,这种影响随水稻生育期而变化,并在水稻生育旺期(孕穗期)达到最大;而且土壤微生物生物量特别是SMBC与土壤酶活性之间具有密切关系.To reveal effects of the elevated CO2 concentration on soil microbial biomass and enzyme activity,typical paddy soil was selected from a subtropical area with a long history of rice cultivation.We studied the contents of soil microbial biomass carbon and nitrogen,and enzymes activity related to soil organic matter degradation(includingβ-glucoside,xylanase and chitinase)under different rice growth period.The results showed that:the plant biomass and soil microbial biomass were increased by the elevated CO2 concentration(800×10-6)comparing to the normal CO2(400×10-6).The soil microbial biomass carbon and nitrogen contents were significantly affected by rice growth stages(P<0.05),which reached to the peak at the rice booting stage.The enzyme activities ofβ-glucoside,xylanase and chitinase were increased by the elevated CO2 concentration(800×10-6)comparing to the normal CO2(400×10-6).All the enzyme activities measured in this study increased in the rice booting stage,and then decreased in the mature stage.The enzyme activity followed the sequence asβ-Glu>Xyl>N-Ac under the same sampling time and CO2 concentration.The multivariate analysis of variance showed that the CO2 concentration and rice growth period significantly influenced the rice plant biomass,soil microbial biomass carbon and nitrogen and the enzyme activity measured in this study.Moreover,the interaction of the CO2 concentration and rice growth period had a significant effect on soil microbial biomass carbon and enzyme activity.Furthermore,the correlation analysis showed that there was a significant positive correlation between soil microbial biomass carbon and soilβ-glucosidase,chitinase and xylanase activities.In conclusions,the elevated CO2 can promote the rice growth,soil microbial biomass and soil enzyme activity.Especially,soil microbial biomass has close relationship with soil enzyme activity.These changes were varying with the rice growth,and all of them reached to the maximum at the rice most productive period(booting stage).

关 键 词：水稻土 CO2浓度倍增 水稻生育期 土壤微生物 胞外酶活性 

分 类 号：X53[环境科学与工程—环境工程]