Ground-truthing of remotely sensed normalized difference vegetation index (NDVI) for improved resource use efficiency in irrigated potato

Crop growth monitoring is important for improved management of farming activities, early detection of crop stress and yield forecasting during the season. Remotely sensed spectral vegetation indices (VIs) allow real-time assessment of crop vegetation status over relatively large area, which is critical for development of management information for potato (Solanum tuberosum L.). However, the nature of the relationship between VIs and ground measured data is not known. Therefore, this study was carried out to validate remote sensing derived growth indices with ground measured potato canopy state variables. Detailed measurements were conducted in 30 commercial irrigated potato fields located in three production regions of South Africa from 2016 to 2022. Information including water and nutrient inputs, drainage, nutrient leaching, crop growth variables, soil water dynamics, and satellite-based normalized difference vegetation index (NDVI) was obtained during the various cropping seasons over the years. The indices were then correlated with ground measured growth parameters using regression analysis. Irrigation management guidelines were developed using the results obtained.