OPTIMAL INTERPOLATION AND ISARITHMIC MAPPING OF SOIL PROPERTIES

Abstract

Summary Soil properties mapped in two intensive surveys had large nugget variances, leading to large estimation variances and erratic isarithms when mapped by punctual kriging. It is likely that both surveyors and survey clients are interested in average values of soil properties over areas rather than point values, and such values can be obtained by block kriging. Estimation variances are very much smaller, and maps of sodium and stone content at Plas Gogerddan, Central Wales, kriged over blocks 920m 2 , and thickness of cover loam at Hole Farm, Norfolk, kriged over blocks of 400m 2 , are much smoother than the punctually kriged maps. The map of Hole Farm has a distinct and meaningful regional pattern.