• ISSN 1008-505X
  • CN 11-3996/S

四川盆地耕地土壤有效磷空间变异特征及影响因素

Spatial variation characteristics and influencing factors of soil available phosphorus in cultivated land in the Sichuan Basin

    摘要
  • 摘要:
    目的 研究耕地土壤有效磷的空间分布特征及其影响因素，对于合理确定磷肥用量和施用方式以及防控面源污染具有重要意义。
    方法 基于四川盆地 4409 个耕地表层(0—20 cm)土壤采样点数据，采用地统计学、相关分析、方差分析和随机森林模型法，分析了该区域耕地表层土壤有效磷的空间分布特征及不同影响因素对耕地表层土壤有效磷空间变异的影响程度。
    结果 研究区土壤有效磷含量平均为20.98 mg/kg，总体处于二级(高)水平。半方差分析结果表明，球状模型为该区域土壤有效磷变异的最佳拟合模型，其块金效应为0.78，决定系数为0.92，属于较弱程度的空间自相关性。土壤有效磷含量空间分布上整体呈现中间低四周高的格局，高值区主要位于成都—雅安一带和涪陵—万县沿线。随机森林模型分析表明，土壤pH、年均降雨量、根系磷输入量、年均气温、成土母岩是该区域土壤有效磷空间变异的主要影响因素，其相对重要性分别为14.54%、8.03%、7.76%、7.37%、7.27%。
    结论 该区域耕地土壤有效磷含量空间分布格局仍主要受土壤pH、气候和成土母岩影响，今后磷肥施用、秸秆还田等需要充分考虑各地土壤酸碱性、气候以及成土母岩的影响。针对土壤有效磷含量较高的区域如成都平原，应注意控制磷素的投入。

     

    Abstract:
    Objectives Understanding the spatial variation characteristics and influencing factors of soil available phosphorus in cultivated land is of great significance for determining the amount and application mode of phosphorus fertilizer and preventing and controlling non-point source pollution.
    Methods Based on the data of 4409 topsoil samples (0−20 cm) in Sichuan Basin, the spatial distribution characteristics of topsoil available phosphorus and the effects of different influencing factors on the spatial variation of topsoil available phosphorus were analyzed by geostatistical method, correlation analysis, variance analysis and random forest model.
    Results The average content of available phosphorus in the study area was 20.98 mg/kg, which was generally in the secondary (high) level. Semi-variance analysis showed that the spherical model was the best fitting model for soil available phosphorus variation in this region, and its bullion effect was 0.78 and coefficient of determination was 0.92, indicating that available phosphorus was mainly affected by random factors. The spatial distribution of soil available phosphorus showed a pattern of low in the middle and high in the surrounding area, and the high-value areas were mainly located in the Chengdu-Ya'an area and along the Fuling-Wanxian area. The random forest model showed that soil pH, annual average rainfall, root phosphorus input, annual average temperature, and soil-forming parent rock were the main influencing factors for the spatial variation of soil available phosphorus in this region, and their relative importance was 14.54%, 8.03%, 7.76%, 7.37%, and 7.27%, respectively.
    Conclusions The spatial distribution pattern of soil available phosphorus content in cultivated land in this region is still mainly controlled by soil pH, climate and patient material, and the application of phosphate fertilizer and straw return should fully consider the influence of soil pH, climate and patient material in the future. For areas with high soil available phosphorus content, such as the Chengdu Plain, attention should be paid to controlling phosphorus input.

     

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