Abstract: Field nutrient distribution map obtained from the study on soil spatial variability and spatial interpolation was the basis of precision nutrient management technique. A 7.9 hectare silage field close to the Agricultural Research Institute at Hillsborough, Northern Ireland, was selected for the study. Grid sampling method (25m25m) was adopted and there were 125 sampling points in this field. Soil available K from part of all samples was taken to produce spatial variability maps using various interpolation methods of Kriging, Inverse distance, Spline, Move average and Trend, and the results of different interpolation were compared by the comparison analysis of mean error (ME) and mean squared error (MSE) using the other part data. The results showed the methods of Kriging and Inverse distance were acceptable.