Fertilization Mapping Based on the Soil Properties of Paddy Fields in Korea

The purpose of this study was to construct a map of expected fertilization rates for nitrogen (N) and phosphorus (P 2 O 5 ) based on measurements of components in soil samples and to identify the spatial variabilities of four lots of a salt-affected paddy field in Korea. Four salt-affected paddy field lots in Korea were divided into 30 sectors for collecting soil samples. They were then analyzed for soil organic matter (SOM), silicon dioxide (SiO 2 ), total nitrogen (TN), and available phosphorus (Av.P 2 O 5 ) in accordance with international standards. Expected fertilization rates of N and P 2 O 5 were developed as prescription standards for the application of fertilizer to paddy fields. They were derived using a model of the fertilization rates of N and P 2 O 5 . To determine the presence of spatial correlation and continuity in the given fields, a spherical variogram was used. Based on the spherical model with the application of a regular kriging interpolation, maps of the contents of TN and Av.P 2 O 5 as well as the expected fertilization rates of N and P 2 O 5 at each sector of 1 × 1 m 2 were developed. The expected fertilization rate of N at each sector appeared in the range of min. 10.0 g to max. 25.7 g, while that of P 2 O 5 appeared in the range of min. 0.68 g to max. 8.46 g.