Using an objective and probabilistic model to delineate homogeneous zones in hedgerow olive orchards

Abstract

In this work, the use of an objective method, the formulation of the Rasch measurement model, which synthesizes data with different units into a uniform analytical framework, is considered to get objetives measures of production potential at some locations of an olive orchard. Thus, nine soil properties (soil apparent electrical conductivity, clay, sand, and silt content, organic matter, total nitrogen, available phosphorous and potassium, and cation exchange capacity) which were measured from soil samples taken at 40 locations in the field were considered. A latent variable, denominated soil production potential, was defined, and later, it was verified, that all soil properties previously indicated have a marked influence on the latent variable. The adequate fit of the data was previously checked to properly compute the Rasch measures. After being integrated in the model, a ranking of all locations according to the soil production potential and the influence on the production potential of each individual soil property were determined. Moreover, those soil samples or properties which have any anomaly where highlighted; this information can be necessary to conduct site-specific treatments, leading to a more cost-effective and sustainable field management. Additionally, estimates using geostatistical algorithms were utilised to map soil production potential and to delineate with a rational basis the management zones in the field.