Geomatics applications offer an opportunity for monitoring spatial variations, and water and nutrient management in banana fields

Jalgaon district of Maharashtra is a major banana producing district of India. The district receives only about 840 mm annual rainfall in less than 50 rainy days and more than 85% of it falls during June to September months of Indian summer monsoon. Mean temperature in summer months is 42.5°C with highest going up to 47.8°C. Growing a long duration crop like banana under such a low rainfall and managing water, particularly in post Indian summer monsoon period is a big challenge. Adaption of drip irrigation system and other modern methods of cultivation was imperative for reaping good harvest. Efficient scheduling of irrigation including its within field distribution is a key requirement for ensuring uniformly good yield from each plant. Geomatics tools like high spatial resolution, multi-spectral satellite images with weekly repeat coverage could support keeping a watch on performance of crop. Sentinel-2 images acquired in green, red and near infrared spectral bands with 5-day repeat coverage have been explored for deriving in-field variability as a surrogate to crop biometric parameters and performance. Temporal satellite images have been transformed to decadal vegetation indices for monitoring the crop throughout the growing period. Banana crop fields have been demarcated on the temporal satellite images for extracting field level image statistics. Analysis of vegetation indices of several dekad (10-day) in a crop season and covering different parts of fields with banana plantations indicated as low as 0% variability in vegetation indices at field level in the case of well managed plantations. However, in many cases within field variability of vegetation indices was around 10% which even exceeded >20% in cases crop management was not optimal. High variability of vegetation indices was corroborated with field observations which indicate the need for application of variable rates of water. This approach can thus be used for managing water and nutrient application. The application of water through the fertigation system did not allow for the assessment of the results for fertilizer and water individually.