The use of ancillary data in field investigations for site-specific agriculture

Three case studies are presented which show how ancillary variables - in this case yield data and remote sensor imagery - can be used to identify the scale and magnitude of within-field variability of key factors for crop management, to define a fuzzy set describing the sampling density required to map a soil property to required precision, and for predicting soil properties on the basis of a limited calibration data set. In this way ancillary data can ensure that maximum value is obtained from costly soil sampling and analysis.