According to the inventory data of the second type inventory of forest resources,three-level regionalization for forestry development and 810 soil sampling data in Henan province,we established SOC depth distribution mass density models for 12 three-level forest areas,selected evaluation parameters for the results of model simulation such as Nash-Sutcliffe coefficient of efficiency (E),percentage error (Ⅴ) and determining the coefficient of determination (R2).Results showed that:SOC density in mineral soils generally decreased with depth;however,this decrease was non-linear and had been frequently modeled as an exponential function.The SOC density in top soil (＜ 20 cm) was significantly affected by vegetation type.The surface (0-20 cm) SOC densities in mountain area were higher than those in plain area,the difference was significant (P ＜ 0.05).The variation of density in the deeper layer (＞ 40 cm) was not consistent with the top layer,soil organic carbon density in the bottom soil layer was significantly affected by soil texture,the density values of sandy soils were higher than those of clayey soils (P ＜ 0.05).Forecast values of top layer of sandy soil had a tendency to be lower,and forecast value of the deep layer might be too high.The model simulation capabilities were relatively high (E ＞ 0.6),and the percentage error was within a range with acceptable accuracy (V ± 15％).The model simulation values were relatively consistent with the observed values.The model could be used to simulate the depth distribution of forest soil organic carbon in 12 forest areas.SOC densities of Henan were lower when SOC densities in the 0-100 cm soil layers were only used to characterize the regional SOC density.When compared with the SOC densities in the range of 0-200 cm in the soil profile,the SOC densities in the 0-100 cm soil layer was about 19.99％ lower than the overall density.%基于河南省林业发展三级区划方案、森林资源二类调查资料和810个土壤有机碳样点数据,构建河南省三级林区土壤有机碳的空间分布模型,选用Nash-Sutcliffe系数(E)、模拟误差(V)和决定系数(R2)等统计参量评估模型的模拟能力.利用模型分析森林土壤有机碳储量的空间分布特征,并估算不同深度的土壤碳储量.结果表明:所有林区土壤有机碳密度值均随深度的增加而呈指数形式迅速下降;表层(＜ 20 cm)土壤有机碳密度受植被类型影响显著,山区表层碳密度值高于平原地区(P＜0.05).底层(＞ 40cm)土壤有机碳密度受土壤质地影响显著,砂质土壤碳密度值高于粘土(P＜0.05),砂质土有较深的有机碳分布;表层土壤有机碳密度预测值有偏低趋势,深层预测值可能偏高;所有模型的Nash-Sutcliffe系数均大于0.6、模拟误差低于±15％,模型可以对土壤有机碳密度值进行估算.若考虑0～200 cm的土壤深度,用0～100 cm深度的有机碳密度值来表征总有机碳密度时结果偏低(偏低约19.99％),砂质土的偏低趋势更加突出.
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