title: Site-specific phosphorus application based on the kriging fertilizer-phosphorus availability index of soils.
abstract: 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.
authors.affiliation: Dep of Post-Modern Agriculture, Ming Dao Univ, Changhua, Taiwan, ROC.
authors.forename: Kai-Wei
authors.initials: KW
authors.lastname: Juang
authors.forename: Day-Chyng
authors.initials: DC
authors.lastname: Liou
authors.forename: Dar-Yuan
authors.initials: DY
authors.lastname: Lee
mesh_terms: D000383:Agriculture; D001682:Biological Availability; D005308:Fertilizers; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis
chemical_list: D005308:Fertilizers; D012987:Soil; D012989:Soil Pollutants; D010758:Phosphorus