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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (2): 22-27.doi: 10.11924/j.issn.1000-6850.casb2022-0063

Special Issue: 耕地保护

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Evaluation of Cultivated Land Soil Fertility Based on Membership Function and Principal Component Analysis

JIANG Bing1,2(), WANG Songtao1,2, SUN Zengbing1,2(), ZHANG Hairui1, WANG Jian1, LIU Yang1   

  1. 1 Shandong Provincial No.4 Institute of Geological and Mineral Survey, Weifang, Shandong 261021
    2 Key Laboratory of Coastal Zone Geological Environment Protection, Shandong Geology and Mineral Exploration and Development Bureau, Weifang, Shandong 261021
  • Received:2022-01-21 Revised:2022-05-02 Online:2023-01-15 Published:2023-01-17

Abstract:

The soil fertility of cultivated land in Gaomi City of Shandong Province was investigated and the spatial distribution of soil fertility was clarified. Eight soil fertility indexes, including soil pH, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzed nitrogen, available phosphorus and available potassium, were acquired by gridded sampling and analysis of surface soil. The membership value of each index was determined by the membership function model of fuzzy mathematics, and the weight of each index was determined by principal component analysis. The integrated soil fertility index was calculated using membership value and weight, and then interpolated for mapping. The results showed that the soil in the study area was mainly alkaline, accounting for 37.77% of the total samples, followed by neutral, accounting for 29.52% of the total samples. Organic matter, alkali-hydrolyzed nitrogen and available potassium were mainly insufficient, total nitrogen and total potassium were mainly medium, and total phosphorus and available phosphorus were mainly rich. The membership value of organic matter and total nitrogen were significantly lower than that of other indexes, showing they were the main limiting factors of cultivated land soil fertility. Total nitrogen had the maximum weight value and contributed the most to soil fertility. Alkali-hydrolyzed nitrogen had the minimum weight value and contributed the least to soil fertility. In the study area, the spatial distribution of integrated soil fertility index of cultivated land was mainly medium.

Key words: cultivated land, membership function, principal component analysis, integrated soil fertility index, fertility evaluation