Monitoring the environmental benefits of Canavalia ensiformis green manure in Thai rice cultivation using PlanetScope satellite data

We investigate the potential of Canavalia ensiformis green manure in enhancing soil fertility, rice growth, and environmental sustainability in Thai rice cultivation. The research integrates field measurements with high-resolution PlanetScope satellite data to monitor the environmental changes induced by green manure application. Fourteen vegetation indices (VIs) were derived from satellite data to assess the impact of green manure on rice growth and development. The results demonstrate short-term improvements in soil organic matter, nitrogen, phosphorus, and potassium levels in the green manure-amended plots, with strong correlations observed between VIs and field-measured parameters. The visible atmospherically resistant index showed the strongest correlations with soil moisture across various depths (r = 0.621 to 0.935, p < 0.01), and the yellow normalized difference vegetation index demonstrated the highest correlation with available phosphorus (r = 0.812, p < 0.05). For rice growth parameters, the carotenoid reflectance indices (CRI Green550) exhibited the strongest correlation with plant height (r = 0.878), and the chlorophyll content estimation indices (Chl Green550) with chlorophyll content (r = 0.642). The normalized difference vegetation index showed the highest correlation with rice yield (r = 0.885). The study highlights the effectiveness of these indices in monitoring soil and plant parameters in response to green manure application. However, the benefits of green manure diminished over time, emphasizing the need for regular application and complementary soil conservation practices. The findings contribute to developing sustainable rice cultivation practices and underscore the potential of integrating green manure with remote sensing technologies to enhance soil health, crop productivity, and environmental sustainability in Thai rice farming systems.