The use of Multiple-Variable Indicator Kriging technique for the assessment of the suitability of an acid soil for maize
Keywords:Multiple-Variable Indicator Kriging technique, Assessment, Acid soil, Maize, Geostatistics
AbstractFor adequate quantification of soil quality, specific indicators need to be measured spatially. The choice of indicators, however, depends on the use to which the quality assessment is to be put. The Multiple-Variable Indicator Kriging (MVIK) method provides a novel means of integrating these factors into a single index. The quality of virgin farmland for maize (Zea mays L.) farming was evaluated on a 250 m x 250 m plot. Soll samples were collected from 100-cm- deep auger holes dug on 30 m x 30 m grids in the field. Soil pH, cation exchange capacity, exchangeable Al+++ , organic C, and soil depth to plinthite were used as indicators for the assessment. The MVIK method was used to integrate these factors into a single index. Based on the variogram of the index, additional points were interpolated by kriging and a suitability probability contour map produced. Area of low probability for meeting the criteria required for maize farming are indicated on the map. Soil conditions responsible for the failure to meet the criteria were identified, and ameliorative measures suggested. The usefulness of this technique for land evaluation for soil management and for environmental purposes was also discussed.