Effects of fire on soil enzyme activities and organic carbon fractions in Pinus massoniana forest
LIU Jundi;LIN Wei;WANG Yuzhe;JIANG Jing;FANG Xiong;YI Zhigang;School of Resources and Environment,Fujian Agriculture and Forestry University;School of Forestry,Fujian Agriculture and Forestry University;
Soil enzymes are involved in the mineralization of soil organic matter( SOM). Forest fire changes soil enzyme activities by changing microbial community structure and thus affects the dynamic processes of soil organic carbon( SOC).The SOC pool is an important component of the terrestrial carbon pool,and forest fire causes changes in SOC fractions. The effects of fire on soil enzyme activities and SOC fractions were assessed using a comparative study on a burned area of typical Pinus massoniana plantation in subtropical China. The results showed that:( 1) Compared with the control,soil p H at depth of 0—10 cm increased dramatically one year after the fire( P 0. 05). Conversely,total soil carbon( TC)concentration decreased by 29.1%( P 0.05),the average of soil total nitrogen( TN) concentration decreased by 17.5%( P0.05). Soil moisture content at 0—10 cm and 10—20 cm were both significantly lower than that of control( P0.05).( 2) Compared with the control,the activity of soil β-glucosidase decreased at depth of 0—10 cm( P0.05); however,soil phenyl oxygenase and peroxidase activities significantly increased( P 0. 05).( 3) One year after the fire,soil microbial biomass carbon,soil particulate organic carbon,and soil readily oxidized carbon concentration at depth of 0—10 cm decreased by 26. 4%,30. 9%,and 2. 69%( P 0. 05),respectively,but soil dissolved organic carbon concentrationdecreased by 19.2% significantly( P0.05). Both layers of soil clay organic carbon concentration tended to decrease( P 0.05).