有机肥施用量对黄河源不同坡向退化高寒草甸土壤团聚体及有机碳的影响

为研究短期内有机肥不同施用量对退化高寒草甸土壤团聚体的影响，以黄河源区退化高寒草甸为研究对象，研究不同有机肥施用量0 kg·m^-2(CK)，0.15 kg·m^-2(M1)，0.45 kg·m^-2(M2)，0.75 kg·m^-2(M3)，1.05 kg·m^-2(M4)，1.35 kg·m^-2(M5)下土壤团聚体稳定性及有机碳含量的变化规律，为探讨青藏高原退化高寒草甸恢复过程中有机肥的最适施肥量提供理论依据。结果表明：土壤团聚体的几何平均直径(Geometric mean diameter，GMD)、平均重量直径(Mean weight diameter，MWD)呈现减少-增加-减少的趋势，在有机肥施用量为0.75 kg·m^-2(M3)时达到最大值。阴坡样地MWD和GMD高于相同处理的阳坡样地。土壤团聚体有机碳含量随着有机肥的施加呈现增长趋势，适量施用有机肥能够增加土壤大团聚体有机碳的含量。阴坡和阳坡不同施肥处理下>0.25 mm的大团聚体对有机碳的贡献率均为最高。

Effects of Different Applications of Organic Fertilizer in Degraded Alpine Meadow on Soil Aggregates and Organic Carbon in the Source Zone of Yellow River

Knowing the consequences of different amounts of organic fertilizer applications to soil aggregates and soil organic carbon in the source zone of the Yellow River on different slopes,to understand the restoration of alpine meadows in Qinghai-Tibet Plateau,this study tried to unveil the relationship of stability of soil aggregates with soil organic carbon concentration in different treatments which were 0 kg·m^-2(CK),0.15 kg·m^-2(M1),0.45 kg·m^-2(M2),0.75 kg·m^-2(M3),1.05 kg·m^-2(M4),1.35 kg·m^-2(M5),respectively. Final results illustrated that the geometric mean diameter (GMD) and mean weight diameter (MWD) of soil aggregates showed the trend of upside-down "V" shape that went decrease-increase-decrease,moreover,M3(0.75 kg·m^-2) had the highest value which means the soil aggregates in this group had the strongest stability. MWD and GMD were both the highest in shady slope combing with the same treatments in sunny slope,while shady ones organic carbon increased with the concentration of the organic fertilizer,the sunny slope had a great contribution to the aggregates upper than 0.25 mm. All treatments on both sides made a great effect on the aggregates upper than 0.25 mm.