【摘要】 采用时空替代法比较研究不同经营年限对柑橘果园土壤团聚体结构及有机碳分配的影响,以探究红壤果园土壤有机碳的稳定性和碳固持能力。结果表明,30 a树龄柑橘园0~20 cm土壤团聚体中>0.25 mm水稳性团聚体比例、平均重量直径和几何平均直径分别比56 a树龄柑橘园高7.6%、10.5%和6.7%,分形维数比56 a树龄柑橘园低1.6%,表明随着经营年限的增加,柑橘园土壤团聚体的稳定性有所降低。种植年限对柑橘园土壤有机碳库特性具有较显著影响,56 a树龄柑橘园0~40 cm土层有机碳储量比30 a树龄柑橘园提高19.4%,微团聚体(粒径<0.25 mm)有机碳储量比30 a树龄柑橘园提高20%~80%;由于与微团聚体结合的有机碳受到物理保护,故56 a树龄柑橘园土壤固碳能力比30 a树龄柑橘园强。更多还原

【Abstract】 Effects of cultivation history of citrus orchard on structure of soil aggregates and soil organic carbon therein were studied using the spatio-temporal substitution method to explore stability of the soil organic carbon in and carbon sequestration capacity of the orchard soil. Results show that a 30-year old orchard was 7. 6%,10. 5% and 6. 7%,higher than a56-year old orchard,respectively,in content,mean weight diameter( MWD) and geometric mean diameter( GWD) of >0. 25 mm water-stable aggregates( R0. 25),but 1. 6% lower in fractal dimension,which suggests that soil aggregates decreased in stability with the cultivation going on. The effect of cultivation on characteristics of the soil organic carbon pool in the orchards was also quite remarkable. The 56-year old citrus orchard was 19. 4% and 20%-80% higher than the 30-year old citrus orchard,respectively,in soil organic carbon storage in the 0-40 cm soil layer and in soil organic carbon storage in micro-aggregates( < 0. 25 mm). As organic carbon combined in micro-aggregates is protected physically,the56-year old orchard was obviously higher than the 30-year old one in soil carbon sequestration capacity.更多还原