基于Meta分析评价污泥施用对土壤团聚体的影响

    Evaluating the effect of sludge application on soil aggregates based on Meta-analysis

    • 摘要:
      目的 利用Meta分析探讨污泥施用促进土壤团聚的效果,并挖掘其影响因素。
      方法 收集整理1990—2023年间已发表文献,在获取的568篇文献中精筛出36篇高度匹配文献,运用Meta分析总结污泥施用对土壤团聚体和土壤性质的影响,并利用线性拟合和随机森林模型等方法,分析污泥施用条件下土壤团聚体与土壤性质的关系。
      结果 污泥施用显著提高土壤大团聚体(粒径>0.25 mm)相对含量以及团聚体平均质量直径;与表施(0.201)相比,污泥混施提高大团聚体相对含量的效应值(0.840)更高;污泥施用均显著提高表层(0~20 cm)和深层(20~40 cm)土壤团聚体平均质量直径,但仅显著增加表层土壤大团聚体相对含量;土壤黏粒含量越低,污泥施用对大团聚体相对含量的效应值越高,土壤黏粒含量<15%、15%~25%与>25%的大团聚体相对含量效应值分别为0.26、0.13和0.05;针对不同污泥施用量,施用量100~200 t/hm2的效应值最高。线性拟合显示污泥施用条件下土壤有机质、碳水化合物、全氮、碱解氮、总磷、速效磷含量和磷酸酶活性均与大团聚体相对含量呈显著正相关;土壤碱化度和土壤电导率与大团聚体相对含量呈显著负相关;随机森林分析进一步确认污泥施用提高土壤有机质和碳水化合物含量是促进土壤大团聚体形成的关键原因;Meta回归表明有机质的增长可以解释93.79%的大团聚体相对含量效应值变异,碳水化合物的增长可以解释76.30%的大团聚体相对含量效应值变异。
      结论 污泥施用增加土壤有机质和碳水化合物含量,进而促进土壤聚集。

       

      Abstract:
      Objective To evaluate the effect and mechanism of sludge application on soil aggregates by using Meta-analysis.
      Method We fine screened 36 papers from 568 papers published in international and domestic journals between 1990 and 2023. The effects of sludge application on soil aggregates and soil properties were evaluated by Meta-analysis. The relationships between soil aggregates and soil properties under sludge application were further analyzed by linear fitting analysis and random-forest method.
      Result Sludge application significantly increased the relative content of soil macroaggregate (particle diameter > 0.25 mm) and the mean weight diameter of aggregates. Compared with surface application (0.201), sludge mixed application had a higher effect size (0.840) in the relative content of macroaggregate . Sludge application significantly increased the mean weight diameter of aggregates in both surface (0-20 cm) and deep ( 20-40 cm) soil layers, but only significantly increased the relative content of macroaggregate in the surface soil layer. The effect size of the relative content of macroaggregate in soils with clay content <15%, 15%~25%, and >25% under sludge application was 0.257, 0.127, and 0.047, respectively, indicating that the higher effect size occurred in soils with lower clay content. For different sludge application rates, the highest effect size was found in rate of 100~200 t/hm2. Linear fitting analysis showed a significant and positive correlation between the relative content of macroaggregate and the contents of soil organic carbon, carbohydrate, total nitrogen, alkaline hydrolyzable nitrogen, total phosphorus, available phosphorus, or phosphatase activity, while a significant and negative correlation between the relative content of macroaggregate and soil exchange sodium percentage or electrical conductivity. Random-forest analysis further indicated that the increase of soil organic carbon and carbohydrate content by sludge application was the main reason for the improvement of soil aggregation. Meta-regression analysis showed that the increase of organic matter could explain 93.79% of the effect size of macroaggregate, and the increase of carbohydrate could explain 76.30% of the effect size of macroaggregate.
      Conclusion The sludge application increases soil organic carbon content and carbohydrate content, and then promotes soil aggregation.

       

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