On-farm rainwater reservoir system optimal sizing for increasing rainfed production in the semiarid region of Africa

Abstract

The low productivity of Burkina Faso’s agriculture is mainly due to the shortage of rainwater during the crucial growing period of crops. This study aims to determine the optimal cultivation surface size of the on-farm rainwater reservoir (OFR) by simulating the upland rice water balance and forecasting the yields under different planting dates’ scenario. For this study, important rice crop information and meteorological variables were collected for computing OFR size in three regions at Burkina Faso, including Gaoua, Fada N’Gourma and Dori in the Sudanian, Sudano-Sahelian and Sahelian zones, respectively. Besides, the suitability of upland and paddy rice in the areas under study is also investigated. From the results of this study, it is observed that the upland rice crop is more suitable than paddy rice while considering the regional rainfall pattern. The upland rice production can possibly have two cycles in the Gaoua and Fada N’Gourma regions. For Gaoua, the planting dates for consecutive production are scaled on April 15 to 23 and August 7 to 14, which require 11.10 and 19.17% of the total farm area to be optimally occupied by the OFR, respectively. For the Fada N’Gourma region, the OFR optimal size requires up to 28.39% of the total area for the first crop (upland rice) planted between April 15 and 23. However, the second crop planted between August 7 and 14 must be a low water consumption and short growing stage crop such as tomato. The Dori region can only have a single production cycle corresponding to the OFR cultivation area of 26.17%. As a result, OFR is able to improve the water availability and mitigate the water stress for reaching the potential yield (7 tons/hectare) through supplementary irrigation option. It is expected to substantially increase the crop productivity by using the OFR system in semiarid regions of Africa.