【摘要】 为探明有机肥替代化肥后土壤团聚体和土壤有机碳的变化特征和作用机制，于2023年在金昌市植物园组繁中心山楂苗圃内进行有机肥替代化肥试验，试验设4个处理，CK：常规施肥，T1：有机肥替代化肥20%,T2：有机肥替代化肥30%,T3：有机肥替代化肥40%，研究了土壤机械稳定性和水稳性团聚体分布、平均重量直径（MWD）、几何平均直径（GMD）、团聚体破碎率（PAD）和有机碳（SOC）变化特征。结果表明，土壤机械稳定性团聚体分布>5 mm粒径占比最高，为34.90%～46.39%；水稳性团聚体分布以<0.25 mm粒径占比最高，有机肥替代化肥显著增加了>5 mm粒径机械稳定性土壤团聚体含量，降低了<0.25 mm粒径水稳性团聚体含量。有机肥替代化肥对土壤团聚体稳定性具有显著影响，土壤机械稳定性团聚体MWD在3.36～4.33 mm范围内，GMD在1.47～2.45 mm范围内；水稳性团聚体MWD在0.29～0.44 mm范围内，GMD在0.15～0.23mm范围内。有机肥替代化肥显著降低了PAD，增加了SOC。相关性分析和随机森林分析结果一致，SOC与机械稳定性团聚体MWD呈显著正相关关系和PAD呈极显著负相关关系；拟合分析结果表明，SOC与PAD的拟合方程为y=2.0625x~2-47.5749x+314.8363,R~2为58.34，对土壤有机碳的变化有更好的解释度。综上，本研究认为有机肥替代化肥可以增加土壤团聚体稳定性，提升土壤碳固存能力。更多还原

【Abstract】 In order to explore the change characteristics and mechanism of soil aggregates and soil organic carbon after organic fertilizer replacing chemical fertilizer, the experiment of organic fertilizer replacing chemical fertilizer was carried out in the Hawthorn Nursery of Jinchang Botanical Garden Group Breeding Center in 2023. There were four treatments in the experiment,conventional fertilization(CK), organic fertilizer replacing chemical fertilizer 20%(T1); organic fertilizer instead of chemical fertilizer30%(T2); the distribution of soil mechanical stability and waterstable aggregates, mean weight diameter(MWD), geometric mean diameter(GMD), aggregate breakage rate(PAD)and organic carbon(SOC)were studied by replacing 40% of chemical fertilizer with organic fertilizer(T3). The results showed that the proportion of>5 mm particle size of soil mechanically stable aggregates was the highest, ranging from 34.90% to 46.39%. The distribution of water-stable aggregates. The content of mechanically stable soil aggregates with a particle size of 5 mm decreased the content of water-stable aggregates with a particle size of <0.25 mm. The substitution of organic fertilizer for chemical fertilizer had a significant effect on the stability of soil aggregates. The MWD of soil mechanical stability aggregates was in the range of 3.36-4.33 mm, and the GMD was in the range of 1.47-2.45 mm. The MWD of water-stable aggregates was in the range of 0.29-0.44 mm, and the GMD was in the range of 0.15-0.23 mm. The replacement of chemical fertilizer with organic fertilizer significantly reduced PAD and increased SOC. The results of correlation analysis and random forest analysis were consistent. SOC was significantly positively correlated with MWD of mechanically stable aggregates and significantly negatively correlated with PAD.The results of fitting analysis showed that the fitting equation of SOC and PAD was y =2.0625x~2-47.5749x +314.8363, and R~2 was58.34, which had a better explanation for the change of soil organic carbon. In conclusion, this study concluded that organic fertilizer replacing chemical fertilizer can increase soil aggregate stability and enhance soil carbon sequestration capacity.更多还原