Effects of Organic Materials on Enzyme Activities and Organic Carbon Concentration in Degraded Mollisol

摘要

The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the concentrations of various organic carbon components in degraded mollisol.This study used a completely randomized factorial design with three application rates of organic fertilizer (M0:0,M1:13.64 g · kg^-1,M2:27.27 g · kg^-1) and biochar (C0:0,C1:1.36 g · kg^-1,C2:2.73 g · kg^-1),resulting in nine treatments with four replicates each.Soil CO₂ flux,organic carbon fractions including the total,active and microbial biomass carbon,and enzyme activities （sucrase,catalase and polyphenol oxidase） were measured over 120 days.Results indicated that the factors and their interactions significantly influenced all measured parameters.Soil respiration peaked at day 15,with M1C2 treatment exhibiting a rate of 10.90-fold higher than the control.The concentrations of the total,active and microbial biomass organic carbon reached maximum values on days 60,30 and 80,respectively.Notably,M2C1 treatment yielded the highest total organic carbon （86.35% increase） and microbial biomass carbon （17.84% increase）.Enzyme activities were significantly enhanced,with the highest catalase activity observed for M0C2 treatment （10.14% increase）.These results demonstrated that the co-application of organic fertilizer and biochar was a effective strategy for improving soil biological health and promoting carbon sequestration in degraded mollisol.The treatment combining a high rate of organic fertilizer with a low rate of biochar （M2C1） was identified as the most promising amendment strategy for fertility restoration.

关键词

degraded mollisol / soil respiration / organic carbon concentration / soil enzyme activity / organic fertilizer / biochar