Soil-terrain modeling for site-specific agricultural management

This chapter focuses on defining the spatial variability of two soil properties that tend to be stable with time and are relevant for describing land quality in glaciated landscapes of the north-central United States; the depth of the A-horizon and depth to free carbonates. There are three basic approaches that have been discussed in regard to mapping soil variability for site specific farming purposes. First, county soil surveys prepared by the national cooperative soil survey program document soil variability at scales typically ranging from 1:12000 to 1:24000. A second approach uses geostatistical interpolation techniques to estimate the spatial distribution of soil properties from a network, usually a grid, of point samples. The third approach includes correlating in-field variability with remote measurements of surface reflectance characteristics and topographic attributes defined by digital terrain analysis.