Characterisation of spatial variability of soils within a vineyard for management zones determination

Abstract

Soils properties within a vineyard usually present spatial variability, inducing variability in plant responses and grape characteristics. The assessment of this spatial variability and its stability is crucial not only to understand different patterns in plant responses, but also to improve vineyard management in relation to production objectives. The aim of this study was to evaluate the soil characteristics of vineyard production systems to determine joint variability and to define management zones (MZ). The field work was carried out for 3 years, and included climatic variations between growing seasons in two rain-fed Tannat vineyards located in Juanicó (Uruguay). Soil electrical conductivity (ECa) data was acquired with an EM38 sensor, soil samples were collected from two depths on a grid (10.8m x 12.5m) design and soil physico-chemical properties were analyzed. We found strong spatial variability patterns across the fields based on clay, silt and sand content, cation concentrations, soil moisture, soil compaction, and ECa, with CV values ranging from 7.5 to 37%. Different potential management zones (MZ) were identified with a geostatistical multivariate approach using a spatially weighted principal component analysis (MULTISPA-PCA) using R software. Different combinations of soil properties were defined and clusters were built in order to define the optimal number of MZ. We conclude that these vineyards can be divided in two distinct MZ delineated mainly by ECa (vertical dipole mode), clay content, organic matter, exchangeable cations (20-40cm soil depth), and soil compaction, to improve vineyard performance.