Analysis of the Relationship between Irrigation Starting Date and Planted Rice Types Using Multi-Temporal Sentinel-2 Satellite Data and Paddy Cultivation Ledger Data

Abstract

To contribute to the formulation of a paddy irrigation plan that matches the actual farming conditions, the irrigation starting date and the planted rice type (use, cultivar) for each rice field were captured in the district, where rice cultivars were diversified, and introduction of rice for new demand was progressing, using multi-temporal Sentinel-2 satellite data and paddy cultivation ledger data. Subsequently, the relationship between irrigation starting date and planted rice types was analyzed based on the irrigation blocks. As a result, it was identified that the area ratio values of the rice fields, where irrigation had started before April 10th, differed greatly between irrigation blocks. One of the factors of the difference was the difference in area ratio of the rice fields planted with 'Akitakomachi' (very early maturing cultivar) between the irrigation blocks. Furthermore, it was identified that the soil puddling period for each cultivation category (early, medium-term, and late cultivations) should not be set uniformly within the target district, but rather for each irrigation block when calculating the required amount of irrigation water.