A Study of the Multivariate Spatial Variability of Soil Properties, and their Association with Vine Vigor Growing on a Clayish Soil

This study aimed to assess the variability of soil properties and its association with vine vigor in a commercial vineyard to identify homogeneous management zones based on soil properties. Soils were sampled on a regular grid. The spatial distributions of several soil properties were mapped and, later, a multivariate technique was employed to delineate site-specific management zones (MZ). Correlation between soil properties variability and normalized difference vegetation index (NDVI) variability was studied, to identify the more efficient method for the delineation of zones. Soil properties that mainly contributed to the soil variation within a vineyard were: apparent soil electrical conductivity (ECa), clay, sand, soil bases, soil moisture, soil penetration resistance, and pH. Two management zones were delineated. Positive relationship between ECa and NDVI was found on one of the vineyards, being the highest grapevine vigor associated with greater clay, calcium, magnesium, pH, and soil moisture content, and lower soil penetration resistance, sand, and sodium content. The opposite trend was observed in the vineyard with higher clay content and greater soil penetration resistance. The characterization of soil spatial variability through multiple variables, proved to be more effective in identifying relevant properties that impact plant vigor when analyzed collectively using geostatistics. The zoning was primarily influenced by properties that determine water and nutrient supply and root development. This study validates a methodology for delineating MZ on clayey soils and raises a question regarding the inverse relationship between EC and NDVI in clayey soils.