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Climate Dependence Of Heterotrophic Soil Respiration From A Soil-translocation Experiment Along Elevation Gradient In The Wuyi Mountain

Posted on:2019-09-27Degree:MasterType:Thesis
Country:ChinaCandidate:Y B RenFull Text:PDF
GTID:2370330575471010Subject:Physical geography
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Subtropical forest ecosystems play a key role in the global carbon cycle,but their response to global warming has not been well explained.The soil-translocation experiment of the elevation gradient provides a unique method for studying the effects of climate change on the carbon(C)cycle and can provide a better explanation for understanding the mechanism of the carbon cycle in mountain forest ecosystems.This paper selects three forest communities soils with different elevation gradients in the national nature reserve of Wuyi mountain in Fujian province.The soil-translocation experiment is used as the research method,the 1400 m soil cores is translocated to 1000 m,the 1000 m soil cores is translocated to 600 m and the 600 m soil cores is translocated to 200 m,respectively.The differences in the heterotrophic respiration of translocated and non-translocated soil cores at different altitudes were analyzed,and the main influencing factors causing the differences were analyzed.The results showed that:1400 m(CF)soil cores translocated to 1000 m(CBF),soil heterotrophic respiration rate increased by 60.10%(P<0.01);1000 m(CBF)soil cores translocated to 600 m(EBF),heterotrophic respiration rate decreased by 10.72%(P<0.05).After 600 m(EBF)soil cores translocated to 200 m(EBF),heterotrophic respiration rate decreased by 3.76%(P>0.05).After soil cores translocation,the Q10 value of 1400 m(CF)soil increased,and the Q10 of 1000 m(CBF)and 600 m(EBF)decreased.The main causes of this change are the following factors:After soil cores translocation,the total soil microbial biomass(PLFAs)decreased at all elevations.The soil microbial community structure of the translocated soil cores(1400 m-T,1000 m-T)tends to be similar to that of the sub-altitude(1000 m-N,600 m-N)in non-translocated soil cores.Soil cores translocation enables the soil microbial community structure to be in a new environment.Rapid adaptation to assimilate the microbial community structure in the new environment,which in turn allows the microbial respiration of the translocated soil cores to resemble the respiration rate at sub-altitude.The translocation of soil labile fraction carbon is the main reason affecting the increase of soil heterotrophic respiration rate in the soil cores pre-translocation(from January to March)at different elevation gradients;Fungi is the main factor affecting the inconsistent changes of soil heterotrophic respiration rates at post-translocation(from April to December).The hydrolases activity increased after soil cores translocation at 1400 m(CF),which promoted soil heterotrophic respiration rate;The hydrolytic enzyme content of 1000 m(CBF)translocation decreased,and soil heterotrophic respiration rate decreased;The change of hydrolase at 600 m(EBF)was not significant,and the corresponding change in soil heterotrophic respiration rate was relatively small.Soil hydrolase are also the other major factors affecting the differences in soil heterotrophic respiration rate after soil cores translocation.
Keywords/Search Tags:Elevation gradient, Soil-translocation, Climate change, Heterotrophic respiration, Soil nutrient, Soil microbial community, Soil enzyme activity
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