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通过对乾县试区土壤定点培肥试验地土壤团聚体及微团聚体的分析测定 ,得出连续不同施肥水平下的土壤有机质含量、各级团聚体及微团聚体数量与组成差异明显。与对照相比 ,随着施肥水平的提高 ,土壤有机质、1 0— 2 5 0μm微团聚体和 >0 .2 5 mm团聚体不断增加 ,<1 0μm的微团聚体含量有下降趋势 ;土壤分散系数减小 ,结构系数增大 ,土壤容重降低 ;特别是施高量有机肥或有机—无机配施 ,更有利于土壤中较大粒径团聚体的形成和土壤结构的改善。相关分析表明 :土壤有机质与 >0 .2 5 mm团聚体和 1 0— 2 5 0μm微团聚体呈极显著正线性相关 ,与 <1 0 μm微团聚体含量呈显著负线性相关。
Soil organic matter content under continuous fertilization was obtained through the analysis and determination of soil aggregates and microaggregates in fixed-point soil fertilization experiment in the dry-land experimental plots. The differences in the numbers and compositions of aggregates and microaggregates at all levels were obvious. Compared with the control, with the increase of fertilization level, soil organic matter, 10-2550μm microaggregates and> 0.255mm aggregates increased continuously, while the content of <10μm microaggregates showed a decreasing trend. Soil disperse The coefficient decreases, the structure coefficient increases, and the soil bulk density decreases; especially the application of high amount of organic fertilizer or organic-inorganic combination is more conducive to the formation of larger aggregate in soil and the improvement of soil structure. Correlation analysis showed that soil organic matter showed extremely significant positive linear correlation with> 0.25 mm aggregates and 10-250 μm microaggregates, and negatively correlated with <10 μm microaggregates.