Avaliação da estabilidade temporal de zonas homogéneas de gestão (ZHG) em pastagens permanentes

Estabilidade temporal de ZHG

Abstract

Precision agriculture (PA) intents to validate technological tools that capture soil and crop spatial variability, which constitute the basis for the establishment of differentiated management zones (MZ). Soil apparent electrical conductivity (EC_a) sensors are commonly used to survey soil spatial variability. Temporal stability of the surveys is essential to ensure correct medium and long-term decisions. In this study, an EC_a contact-type sensor (Veris 2000 XA) and an electromagnetic induction sensor (EM-38) were used in four fields of dryland pastures in Alentejo region of Portugal. The first survey was carried out in October 2018 and the second was carried out in September 2020. The aim of this study was to assess the temporal stability of EC_a patterns using different types of sensors. Data processing involved synchronizing geographic coordinates obtained by the two types of EC_a sensors in each location and establishing MZ based on geostatistical analysis of altimetry and EC_a data. Although the basic technologies have different principles (contact versus non-contact sensors), the surveys were carried out at different soil moisture conditions and were temporarily separated (about 2 years), EC_a measurements showed statistically significant correlation in all experimental fields, which was reflected in spatially stable patterns of the MZ maps. These results provide perspectives for future developments, which will need to occur in the creation of algorithms that allow validating the spatial variability and temporal stability of EC_a through smart soil sampling and analysis to allow recommendations for sustained soil amendment or fertilization.