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研究了重庆四面山低山丘陵区不同水土保持林地0～20、20～40和40～60 cm的土壤有机碳含量及不同深度的土壤有机碳密度。结果表明:0～20、20～40和40～60 cm土层中土壤有机碳含量的平均值分别为33.09、7.51和3.21 g/kg;0～20 cm的土壤有机碳密度介于4.97～14.31 kg/m2,而0～60 cm的土壤有机碳密度介于7.84～17.94 kg/m2,均值为12.78 kg/m2;土壤有机碳含量和有机碳密度随土壤深度增加而显著减少,但其减少程度随水土保持林树种组成不同而异;不同水土保持林地60 cm深度的土壤有机碳密度存在显著差异,表现为:天然次生林>人工林>农耕地,其中,天然阔叶混交林土壤有机碳密度最大,为17.94 kg/m2,农耕地的最小,仅为7.84kg/m2。人工水土保持林中,阔叶混交林的土壤有机碳密度最大。从增加土壤碳的角度,建议营造阔叶混交林。
The soil organic carbon contents and soil organic carbon densities at 0 ~ 20, 20 ~ 40 and 40 ~ 60 cm in different soil and water conservation forest in the hilly area of Chongqing Simian Mountain were studied. The results showed that the average contents of soil organic carbon in 0-20, 20-40 and 40-60 cm soil layers were 33.09, 7.51 and 3.21 g / kg, respectively. The soil organic carbon density in 0-20 cm ranged from 4.97 to 14.31 kg / m2, while that of 0-60 cm ranged from 7.84 to 17.94 kg / m2 with an average of 12.78 kg / m2. Soil organic carbon and organic carbon concentrations decreased significantly with soil depth increasing, but the degree of decrease There are significant differences in soil organic carbon density at 60 cm depth between different soil and water conservation forests, as follows: natural secondary forest> artificial forest> agricultural land, in which the density of soil organic carbon in the natural broad-leaved mixed forest is the largest , 17.94 kg / m2, the smallest farming land, only 7.84kg / m2. Among the artificial soil and water conservation forests, the broad-leaved mixed forest has the highest soil organic carbon density. From the perspective of increasing soil carbon, it is recommended to create a broad-leaved mixed forest.