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用湿筛方法测定了长期田间肥料定位试验地耕层0～20cm土壤水稳性团聚体含量,研究了施肥对黑土团聚体组成、根际沉积碳在土壤团聚体中分配的影响。试验共设无肥(CK)、化肥NP(NP)、化肥NK(NK)、化肥PK(PK)、化肥NPK(NPK)和化肥NPK+有机肥(NPKM)6个处理。采用尼龙网框分隔法区分根际土和非根际土,差减法计算根际沉积碳的分配。结果表明:根际沉积碳主要增加>2mm的团聚体的形成,减少0.25～0.5mm团聚体的形成。CK、NP和NK处理的根际沉积碳增加MWD,PK处理则减少MWD。长期施用化肥使土壤各粒级团聚体有机碳含量增加,表现为NPKM>NPK>NP>PK>NK>CK的趋势。CK处理根际沉积碳分配到>2mm,2～1mm大团聚体和<0.25mm微团聚体中;缺素(NP、NK、PK)根际沉积碳分配到0.5～2mm大团聚体和<0.25mm微团聚体中;化肥配施有机肥减少1～2mm和0.25～0.5mm粒级根际沉积碳分配比例,增加0.5～1mm和<0.25mm粒级分配比例。
The wet-sieving method was used to measure the water-stable aggregates content of 0-20 cm soil layer in the long-term field experiment of fertilization. The effects of fertilization on the composition of black soil aggregates and the distribution of carbon in the rhizosphere soil aggregates were studied. There were 6 treatments including CK, NP, NK, PK, NPK and NPKM. Rhizosphere soil and non-rhizosphere soil are distinguished by nylon mesh separation method, and the distribution of carbon deposition in rhizosphere is calculated by subtraction method. The results showed that the rhizosphere sediment carbon mainly increased the formation of agglomerates> 2 mm and decreased the formation of 0.25-0.5 mm aggregates. The rhizosphere deposition carbon of CK, NP and NK increased by MWD, while PK treatment reduced MWD. Long-term application of chemical fertilizers increased soil organic carbon content in all fractions, which showed the trend of NPKM> NPK> NP> PK> NK> CK. The rhizosphere sediment carbon of CK was distributed to> 2mm, 2 ~ 1mm macroaggregates and <0.25mm microaggregates. The rhizospheric sediments of NP (NP, NK, PK) were distributed to 0.5 ~ 2mm macroaggregates and <0.25 mm microaggregates. Fertilizer combined with organic manure reduced the carbon deposition ratio in the rhizosphere of 1 ~ 2mm and 0.25 ~ 0.5mm fractions, and increased the fractional distribution of 0.5 ~ 1mm and <0.25mm fractions.