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This article in JEQ

  1. Vol. 31 No. 4, p. 1248-1255
    Received: July 3, 2001

    * Corresponding author(s): dylee@ccms.ntu.edu.tw
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Site-Specific Phosphorus Application Based on the Kriging Fertilizer-Phosphorus Availability Index of Soils

  1. Kai-Wei Juanga,
  2. Day-Chyng Lioub and
  3. Dar-Yuan Lee *b
  1. a Dep. of Post-Modern Agriculture, Ming Dao Univ., Peitou, Changhua, Taiwan, R.O.C
    b Graduate Inst. of Agricultural Chemistry, National Taiwan Univ., Taipei, Taiwan, R.O.C


Site-specific phosphorus management is done to optimize crop production and minimize P loss from soils. The spatial variability of the available P prior to fertilizer application and the P-fixation tendency of soil both need to be taken into account for variable-rate P application. The objectives of this research were to document the spatial variability of the fertilizer-P availability index, which shows the P-fixation tendency, and to develop a strategy that takes the spatial distribution of this index into account for site-specific phosphorus application. In this study, the spatial patterns of the fertilizer-P availability index were characterized by using geostatistics. The ordinary kriging was used for spatial interpolation of the fertilizer-P availability index. Because the fertilizer-P availability index of soil is related to oxalate-extractable Fe and Al and because measuring oxalate-extractable Fe and Al is much easier than directly determining the fertilizer-P availability index, the spatial distribution of the fertilizer-P availability index can be obtained using the oxalate-extractable Fe and Al data. The spatial distribution of Olsen-extractable P, which was used to measure the available-P status prior to fertilizer-P application, was also estimated by using ordinary kriging. The required fertilizer-P amounts were then determined using the kriging estimates of the fertilizer-P availability index and Olsen-extractable P. A fertilizer-P recommendation map for the 430-ha study site in Changhua county, Taiwan was generated by using this approach for illustration. The proposed method for generating fertilizer-P recommendation maps can be used for variable-rate application to maintain an adequate P status for crop production and to potentially reduce the P loss from soils.

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Copyright © 2002. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.31:1248–1255.