基于小尺度的山地柑橘园土壤有效磷空间分布状况研究

Spatial distribution of available soil phosphorus in the hilly citrus orchards based on small scale samples

【目的】研究山地柑橘园土壤有效磷的空间分布状况。【方法】以ArcGIS Geostatisties模块为工具,通过小尺度采样,对土壤有效磷含量空间分布状况进行地统计分析。【结果】传统统计分析结果表明,研究区有效磷含量原始数据经域法处理和对数转换后呈正态分布,其平均值为20.13 mg·kg-1,变异系数为123.05%,属于强变异程度。地统计分析表明,研究区有效磷含量空间变异具有明显的二阶趋势和各向异性特征;其最佳半方差函数符合指数模型,具有中等程度的空间相关性[C0/(C0+C)=36.55%],是结构性因素和随机性因素共同作用的结果。通过普通Kriging插值,显示研究区有效磷含量分布呈较明显东西方向较高,南北方向较低的分布态势。以土壤营养分级标准对该果园土壤有效磷进行插值研究表明,试验园30.91%的区域土壤有效磷处于极缺乏状态,27.27%处于缺乏状态,36.36%为适量状态,5.45%为过量状态。【结论】该园区土壤磷素营养整体较为贫乏,应实行分区差异化管理。试验园地形地貌、土壤养分及管理方式等均是影响土壤有效磷空间变异的因素。研究结果为柑橘园磷素合理高效管理提供了理论依据。

[Objective]The aim of the research is to study the spatial distribution of available soil phospho- rus in the hilly citrus orchards. [Method]The spatial distribution of available phosphorus content （APC） in soil was investigated using ArcGIS Geostatisties software based on geographical statistics. The small scale samples used in this study were collected from citrus mountain orchards in Fengjie County, Chongqing, China. [Result]The results of traditional statistical analysis showed that the data appeared in normal dis- tribution after they were processed by domain method and logarithmic transformation, with an average of 20.13 mg/kg and a variation coefficient of 123.05% that was a high degree of variation. The results from geographical statistics also indicated that the spatial variability of APC was obviously characterized by a second-order trend as well as anisotropy. Its optimal semi-variance function fitted an exponential model with moderate spatial correlation [Co/（Co＋C）=36.55%], which resulted from structural and the stochastic factors. The results via ordinary Kriging interpolation showed that the APC in the east and west was higher than that in the north and south. According to the grading standards of soil nutrients, the areas in this study were classified into four types based on the APC data after the interpolation, i.e. significantly defi- cient, generally deficient, moderate and excessive with the percentage of 30.91%, 27.27 %, 36.36% and 5.45%, respectively.[Conclusion]Based on the data in this study, overall the soil phosphorus nutrition in this area is relatively poor. This study will provide a basis for rational and efficient phosphorus manage- ment in citrus orchards.