| Global climate change and human disturbance can lead to changes in forest surface soil traits,which in turn affect soil organic carbon turnover and nutrient cycling.However,due to the lack of comprehensive and systematic experimental exploration,the current changes in forest soil environment in the study of global change have led to a lack of understanding of the changes in soil organic matter.In this study,the effects of acid-alkaline substances addition on soil organic carbon fraction and soluble sugar content in Pinus tabulaeformis forests were studied by adding acid-alkaline substances in Pinus tabulaeformis forests to understand the intrinsic transformation process of soil organic matter in Taiyueshan Pinus tabulaeformis forest.Provide a theoretical basis.In this study,ammonium nitrate(NH4N03)and soda lime were applied to the surface of Pinus tabulaeformis forest in May each year.so that the acid application level of the plot was 0.(Control),5,10,20,40 g/(m2ˇyear),hereinafter referred to as N0,N5,N10,N20,N40;alkali levels are 0(control),50,100,200,400 g/(m2ˇyear),hereinafter referred to as H0,H50,H100,H200,H400.The organic carbon,microbial biomass carbon,microbial activity,microbial metabolic entropy,soluble sugar and soil total nitrogen in 0-10 cm and 10-20 cm soil layers were determined,and soil soluble sugar and organic carbon components and microorganisms were analyzed.Correlation of ecological characteristics.The study yielded the following results:(1)After the addition of ammonium nitrate,low-concentration acid treatment(N5,N10)had no significant effect on the indicators other than soil soluble sugar in the 0-10 cm soil layer.After high concentration of acid treatment(N20,N40),the SOC content decreased by 23.46%and 28.16%,respectively;the MBC content decreased by 26.13%and 40.38%compared with N0;the DOC content increased by 51.64%and 64.05%,respectively,compared with N0 treatment;The microbial activity increased by 45.38%and 36.95%compared with N0;the metabolic entropy increased by 104.43%and 135.92%respectively compared with N0;the soluble sugar content of N5,N10,N20 and N40 increased by 81.67%100.13%,127.73%and 171.21%.In the 10-20 cm soil layer,the soluble sugar content of N40 treatment was significantly increased by 81.08%compared with N0,and the rest was not significantly different from No.(2)After adding soda lime,there was no significant change in SOC and microbial activity in 0?10 cm soil layer;MBC content decreased by 32.14%after H200 treatment;DOC after H50,H100,H200,N400 treatment was higher than H0 The decrease of 36.19%,45.74%,45.92%,and 44.25%;the LBC content increased by 69.24%,48.05%,53.66%,and 64.80%,respectively;the soluble sugar after H200 and N400 treatment increased by 49.58%and 102.37%,respectively.In the 10-20 cm soil layer,there was no significant change in each index.(3)After the addition of acid and alkali substances,there was a significant positive correlation between soil soluble sugar and soil organic carbon,microbial biomass carbon,microbial activity and microbial metabolic entropy. |
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