Phenophase-wise Crop Weather Calendar Development and Satellite-based Validation for Paddy in the Tungabhadra Command Area

Abstract

A study was conducted during 2024–2025 at the Krishi Vigyan Kendra (KVK), Gangavathi, Koppal District, Karnataka, under the Gramin Krishi Mausam Sewa (GKMS) scheme of the India Meteorological Department (IMD) to develop and evaluate a location-specific crop weather calendar for paddy in the Tungabhadra Command Area. The calendar was prepared by integrating long-term weekly climatic normals (2008–2023), phenophase-wise crop growth stages, and weather conditions conducive to major insect pests and diseases. The rice crop (medium-duration variety ‘Gangavathi Sona’) was analysed from the 25th to the 44th Standard Meteorological Week (SMW), covering the complete crop season from transplanting to harvest. Favourable weather conditions for higher productivity were observed during the maximum tillering stage, characterised by maximum temperatures of 30.9–32.6 °C, minimum temperatures of 23.6–24.0 °C, rainfall of about 93 mm, and morning relative humidity of 81–85 per cent. The calendar also identified weather regimes conducive to major pests and diseases, including brown planthopper, gall midge, rice blast, and bacterial leaf blight, thereby providing critical risk windows for advisory interventions. Satellite-based crop growth dynamics were analysed using 16-day MODIS NDVI (250 m) time series for the kharif season, which showed strong temporal agreement with the phenological progression depicted in the crop weather calendar. Plot-level NDVI profiles extracted for selected farmers’ fields further confirmed consistency among satellite-derived crop growth trajectories, calendar-based crop stages, and field observations. The practical utility of the crop weather calendar was evaluated through structured feedback from selected rice-growing farmers. Most respondents perceived the advisories as useful to moderately useful, particularly for pest and disease management, and reported yield improvements and additional economic benefits ranging from ₹1,400 to ₹2,600 per acre. Although based on a limited sample size, the feedback indicated that crop weather calendar–based advisories supported improved decision-making, reduced weather-related risks, and enhanced economic returns. Overall, the study indicates that integrating crop weather calendars with satellite-derived indicators and farmer feedback can strengthen phenophase-specific, weather-based advisories under GKMS, especially in intensively cultivated canal command areas.