不同施肥处理下桉树混交林土壤肥力评价

Evaluation of Soil Fertility in Eucalyptus Mixed Forests Under DifferentFertilization Treatments

以桂西南地区广西国有派阳山林场桉树混交林为研究对象,监测其土壤pH值、有机质、全量养分和速效养分等8个化学性质指标,采用秩和比综合评价法、优劣解距离法、主成分分析法,因子分析法和熵值法5种土壤肥力质量评价方法,对比验证不同评价体系和模型,探讨桉树混交林土壤肥力质量现状。结果表明:(1)综合5种评价方法,桉树混交林土壤综合评价比较为:B1>B>B2>A1>A>A2,提质组土壤肥力显著高于常规组,上层土壤肥力显著高于下层土壤。(2)5种评价方法中,秩和比综合评价法、熵值法和因子分析法3种评价方法土壤肥力评价排名完全一致。其中秩和比综合评价法线性模型表现优秀、构建良好。(3)8个土壤化学性质指标的权重比较为:全钾>速效磷>全磷>全氮>速效钾>速效氮>有机质>pH值。权重排名前三的全钾、速效磷和全磷占比54.9%。(4)土壤化学性质指标变化幅度较大,其中有机质、全氮和速效氮、全钾和速效钾养分分级标准均跨越了3个或以上等级,全磷和速效磷均表现为低或很低水平,pH表现为酸性或强酸性水平。(5)提质组A土壤呈现出酸性、有机质中等,全量元素分别为极高、低和高等级,速效元素分别为极高、极低和很高等级;常规组B土壤呈现出酸性、有机质中等,全量元素分别为高、高和很低等级,速效元素分别为极高、极低和低等级。提质组对照常规组,土壤酸性下降了4.64%,有机质、全氮和全钾分别提升了19.35%、52.37%和777.33%,速效磷和速效钾分别提高了173.41%和340.76%,全磷和速效氮含量则相反,提质组较常规组下降了27.53%和4.12%。

The mixed Eucalyptus forest in the State-owned Paiyangshan Forest Farm in southwestern Guangxi was taken as the research object.Eight chemical property indicators,such as soil pH,organic matter,total nutrients,and available nutrients,were monitored.Five soil fertility quality evaluation methods,including rank sum ratio comprehensive evaluation method,superior and inferior solution distance method,principal component analysis method,factor analysis method,and entropy value method,were used to compare and verify different evaluation systems and models,and to explore the current status of soil fertility quality in the mixed Eucalyptus forest.The results showed that:①Based on five evaluation methods,the comprehensive evaluation ranking of soil in Eucalyptus mixed forests was B1>B>B2>A1>A>A2.The soil fertility of the improved group was significantly higher than that of the conventional group,and the upper soil fertility was significantly higher than that of the lower soil.②Among the five evaluation methods,the rank sum ratio comprehensive evaluation method,entropy method,and factor analysis method rank the soil fertility evaluation completely consistent.The linear model of the rank sum ratio comprehensive evaluation method performs well and is well constructed.③The weight ranking of 8 soil chemical property indicators is total potassium>available phosphorus>total phosphorus>total nitrogen>available potassium>available nitrogen>organic matter>pH.The top three in terms of weight are total potassium,available phosphorus,and total phosphorus,accounting for 54.9%.④The changes in soil chemical property indicators are significant,with the grading standards for organic matter,total nitrogen and available nitrogen,total potassium and available potassium nutrients all spanning three or more levels.Total phosphorus and available phosphorus are both at low or very low levels,and pH is acidic or strongly acidic.⑤The soil of group A shows acidity and moderate organic matter,with total elements of extremely high,low,and high grades,and available elements of extremely high,extremely low,and very high grades,respectively;The conventional group B soil exhibits acidity and moderate organic matter,with total elements at high,high,and very low levels,and available elements at extremely high,very low,and low levels,respectively.Compared with the conventional group,the soil acidity of the improved group decreased by 4.64%,while organic matter,total nitrogen,and total potassium increased by 19.35%,52.37%,and 777.33%,respectively.Available phosphorus and potassium increased by 173.41%and 340.76%,respectively.The content of total phosphorus and available nitrogen was the opposite,while the improved group decreased by 27.53%and 4.12%compared to the conventional group.