18. Evaluation of the soil quality of Chilean orchards using a gamma radiation sensor

Soil mapping is a key element to successfully implement Integrated Nutrient Management (INM) in high value crops. There are several soil mapping techniques, many of which are aided by proximal sensors. The objective of the present work was to evaluate the agronomics behind the mapping results using a gamma radiation sensor in Chilean fruit orchards. Results from over 2,000 ha mapped are presented. The technology has demonstrated its value in determining the most limiting factors in new and established orchards, and the possibility of correcting them in a site-specific manner. The identified limiting factors (LF) have varied widely and have included low pH, P and K deficiencies, excess Na, high salinity, copper toxicity, and low buffer capacity, among others. An important use for the technology is the site-specific estimation of N mineralization as well as the available N, and from them a better N balance and a proper estimation of the Nitrification Inhibitor (NI) rates.