外源有机物料长期施用对黄泥田团聚体稳定性和有机碳氮积累的影响OA

To investigate the effects of long-term application of different organic materials on the stability of soil ag-gregates and the contents of organic carbon and total nitrogen in soil aggregates of yellow clayey paddy soil,a field plot experiment was carried out in a rice paddy field in Jinhua City,Zhejiang Province of China from 2011 to 2023.Three treatments were designed in the experiment,namely chemical fertilizer alone(NPK),combined application of chemical fertilizer and straw with rapid decomposer(RS),and combined application of controlled-release bulk-blen-ded(BB)fertilizer and decomposed cow manure(CM).Topsoil(0-20 cm)samples were collected after the late rice harvest in 2023.Soil aggregates with different particle sizes were separated by the wet sieving method.The pro-portion(mass fraction),organic carbon content and total nitrogen content of aggregates in each particle size fraction were determined.The mean weight diameter(MWD),geometric mean diameter(GMD)and the proportion(mass fraction)of soil aggregates＞0.25 mm(R0.25)were calculated,and the storages of organic carbon and total nitrogen in aggregates of each particle size fraction were estimated.The results showed that compared with the NPK treatment:the RS treatment significantly(p＜0.05)reduced the proportion of aggregates with particle size ≤0.25 mm in the soil;the CM treatment significantly decreased soil bulk density and the proportion of aggregates with particle size≤0.25 mm,and significantly increased the proportion of aggregates with particle sizes of＞2.00 mm and＞0.25-1.00 mm,as well as the values of MWD,GMD and R0.25.Compared with the NPK treatment,the CM treatment sig-nificantly increased the organic carbon storage and its contribution rate of aggregates with particle sizes of＞2.00 mm by 66.91％and 11.23 percentage points,respectively,and significantly increased the total nitrogen storage of aggre-gates with particle sizes of＞2.00 mm by 43.89％.Correlation analysis indicated that the stability of soil aggregates was mainly affected by aggregates with particle sizes of＞2.00 mm and＞0.25-1.00 mm.Overall,both the CM and RS treatments contributed to improving the stability of soil aggregates and the storages of organic carbon and total nitrogen in soil aggregates,and the effect of the CM treatment was superior to that of the RS treatment.Therefore,the combined application of controlled-release BB fertilizer and decomposed cow manure can be adopted as an effec-tive measure to enhance the stability of soil aggregates and regulate the soil organic carbon pool and nitrogen pool in yellow clayey paddy soils in central Zhejiang.