Determination of pluvial rice optimum seedling periods in Middle-west of Côte d'Ivoire

This study aims to identify the optimal time of planting upland rice in the Center-west of Côte d'Ivoire which is located between longitudes 5º and 7º30 and latitudes 5º30 and 7 º. The method used is that of Eldin that tracks the plant water status by region and decade after decade to determine the vegetative periods in the year. The study focuses on rice 90 and 105 days. The data used are the values of the decadal rainfall on the normal 1971-2000 and information's about upland rice of 90 and 105 days and decadal crop coefficients.The results indicate that the first growing season (first cycle) is generally between early April and early July and lasts 3 months. The second growing season (one cycle) is between August 11 and November 10 and lasts up to 2 months 10 days. In first crop cycle, the optimum planting dates of upland rice of 90 days must start between 11 and 30 April and the rice of 105 days between March 1 and April 20 depending on the location. In single crop cycle, the upland rice of 90 days should be planted between July 21 and August 20 and rice of 105 between July 1 and August 21 depending on the location of the study area.