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Journal of Agriculture ›› 2025, Vol. 15 ›› Issue (11): 41-48.doi: 10.11923/j.issn.2095-4050.cjas2024-0130

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Comparative Study on Spatial Interpolation Methods of Cultivated Soil Nutrients in Minhe County Based on GIS

LI Youwei1(), ZHANG Junda2, CAI Liqun1()   

  1. 1 College of Resources and Environment, Gansu Agricultural University, Lanzhou 730070
    2 Cultivated Land Quality Monitoring and Protection Center, Ministry of Agriculture and Rural Affairs, Beijing 100125
  • Received:2024-07-02 Revised:2024-11-21 Online:2025-11-20 Published:2025-11-19

Abstract:

This study investigated the spatial variability of soil nutrients and evaluated various spatial interpolation methods in Minhe County, Qinghai Province. This study employed GIS spatial analysis and geostatistical methods to analyze the spatial variability of soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) and available potassium (AK). The research aimed to determine the most suitable spatial interpolation method for each nutrient. The results showed that moderate spatial variability for all nutrients, with AK exhibiting the highest variation at 55.5%, while other nutrients ranged from 34.5% to 54.8%. Spatial distribution patterns revealed higher concentrations of soil organic matter and TN in the northwest decreasing towards the southwest. AP displayed a more uniform distribution, whereas AK was highest in the central region, gradually declining northward. Interpolation accuracy assessments indicated that the common Kriging method was optimal for SOM, AP, and AK, while the radial basis function method proved most accurate for TN. These findings provided valuable insights into the spatial distribution of soil nutrients in Minhe County and offer guidance for selecting appropriate interpolation methods in similar regions.

Key words: GIS spatial analysis, soil nutrients, spatial interpolation, semi-variance function, geostatistics, cross verification, interpolation method