Spatially variable pesticide application in vineyards: Part I, developing a geostatistical approach

A geostatistical methodology is presented to optimise the dosage of plant protection products (PPP) in vineyards with spatial variability. Sprayers are commonly used in viticulture to apply a constant volume rate per unit ground area (1 ha(-1)). This can be a problem in vineyard plots with remarkable spatial variability in vine vigour, being necessary guiding winegrowers through a decision-making tool to determine an appropriate uniform volume rate. The leaf area index (LAI), measured by a terrestrial LiDAR scanner at high spatial resolution along crop rows, can be used to determine the optimum volume application rate. The proposed method is based on obtaining different probability maps of LAI by applying an indicator kriging to the original LAI data. As a result, this method allows winegrowers to i) map and locate areas within the plot that, within a given confidence level (70% or 90%), exceed or do not exceed different values (percentiles) of the original LAI, and ii) set the LAI and the corresponding volume rate seeking, for example, to balance the probability (risk) of areas with lower and higher doses than required. In more conservative protection strategies, the method also allows farmers to set the values of LAI and volume rate that greatly minimise the probability of vulnerable areas being underdosed. (C) 2020 IAgrE. Published by Elsevier Ltd. All rights reserved.