毛竹林土壤易氧化有机碳区域分异及影响因素OA北大核心CSTPCD

[Objective]The vertical and latitudinal distribution of soil easily-oxidized organic carbon(EOC)in the north subtropical,middle subtropical,and south subtropical regions of Phyllostachys edulis forests were studied to reveal the main influencing factors of its regional differentiation,which provided scientific basis for carbon sequestration,management,and stability of soil organic carbon pool in P.edulis forests.[Method]Through field investigation and experimental analysis,the variation rules of soil easily-oxidized organic carbon content along soil layer and latitude was revealed.Factor detection,interaction detection and risk detection of geodetector were used to analyze the factors affecting the regional differentiation of soil easily-oxidized organic carbon.[Result]1)Soil easily-oxidized organic carbon content of P.edulis forests decreases with deepening of soil layers in each region,but its proportion to total soil organic carbon increased with the deepening of soil layer.Easily-oxidized organic carbon contents of 0-60 cm soil layer of northern subtropical P.edulis forests(5.16 g·kg-1)was higher than that in the middle(4.56 g·kg-1)and southern(4.86 g·kg-1)subtropics.The stability of soil carbon pool decreased with decreasing latitude.2)Mean annual temperature(MAT)was the most important factor in explaining soil easily-oxidized organic carbon of P.edulis forests,with q values ranging from 0.376 to 0.452,followed by elevation(q=0.392,P＜0.001).Among the stand factors,the litter thickness had significant effects on soil easily-oxidized organic carbon in different soil layers,and stand biomass of P.edulis had a significant effect on easily-oxidized organic carbon for 30-60 cm soil layer.(q=0.308,P＜0.01).3)The interaction effects between all factors were synergistic.The interaction between stand biomass and litter thickness for 0-10 cm layer was the strongest(q=0.704).The interaction between stand biomass and mean annual temperature was the strongest for 10-30 cm and 30-60 cm soil layers,and the q values were 0.601 and 0.732,respectively.Both of them showing non-linear enhancement.4)Soil easily-oxidized organic carbon contents was significantly different between different mean annual temperature ranges and was highest at 17-19 ℃(5.03-12.39 g·kg-1)and lowest at 15-17 ℃(2.69-6.20 g·kg-1).Soil easily-oxidized organic carbon contents was highest in each soil layer at elevation of 700-900 m.The highest easily-oxidized organic carbon contents was reached at a layer of 0-10 cm when stand biomass was 75-90 t·hm-2.[Conclusion]The content of easily-oxidized organic carbon in the soil of the P.edulis forests decreased with the deepening of the soil layer,and its proportion in the total soil organic carbon content showed the latitudinal distribution of north subtropics＜middle subtropics＜south subtropics.Therefore,forest management with slight disturbance should be implemented in the lower latitudes to reduce soil disturbance and improve the stability of soil organic carbon in the P.edulis forests.Mean annual temperature and elevation were the key factors influencing soil easily-oxidized organic carbon of P.edulis forests.Stand biomass also had significant effects on the easily-oxidized organic carbon in each soil layer and there were significant synergistic effects with climate and topography factors.The single-factor effects of climate,topography,stand condition and their interaction effects together dominated the spatial variation of soil easily-oxidized organic carbon in P.edulis forests at regional level.A scientific basis was provided for the stability of soil active organic carbon and the potential of carbon sequestration.