Enhancing precision agriculture with cosmic-ray neutron sensing: monitoring soil moisture dynamics and its impact on grapevine physiology

Cosmic-ray neutron sensing (CRNS) has emerged as a reliable tool for continuous, non-invasive soil moisture (SM) estimation across large areas and soil depths, aiding irrigation strategies. However, challenges like data interpretation and integration persist. This study examines CRNS's efficacy in monitoring SM and its impact on grapevine physiology. The study was conducted in a vineyard (Vitis vinifera L.) located at Imola (Bologna, Italy) within an area of approximately 12 ha and with two local grape varieties, Pignoletto (PG) and Trebbiano romagnolo (TR). The vineyard’s irrigation system is a subsurface drip irrigation (SDI) located at 25 cm depth. A CRNS probe was installed and calibrated together with a static point-scale SM sensor for comparison. In addition, three campaigns with a portable point-scale sensor to assess SM spatial variability were carried out. Based on that, different SM zones have been identified and further investigated. Consequently, 80 vines were selected, equally proportioned between the two grape varieties, and considering the SM zones. Out of those vines, midday stem water potential (ψstem) was evaluated taking into account the irrigation management and grape ripening stage. After veraison, berry samples were analyzed, assessing the evolution of total soluble solids, pH, and titratable acidity. Empirical evidence confirms CRNS's effectiveness in detecting SM changes up to 25 cm deep from sub-surface irrigation. It correlates well with the point-scale sensor, reflecting SM dynamics accurately throughout the irrigation events. Variations within grape cultivars and moisture zones were discerned through grapevine physiological assessments. Despite the spatial variability observed, the results concerning vine water status and grape berries composition exhibited scarce variations. While highlighting CRNS's potential for water management support, this study underscores the need for integrated approaches in assessing spatial variability and tailoring irrigation strategies, particularly in extensive vineyards, considering vine physiological responses.