Rainfall Variability Impacts On Rice Production: A Case Study Of Rice Yield In The Administrative Unit Of Collines In Benin, West Africa

Abstract

Rice is considered as key crop in the strategic planning to revitalize the agricultural sector to a level of self-sufficiency, reduce poverty as specified in the National Rice Strategic Plan. To place rice as a strategic crop in Benin, there is need to have information on both physical and human factors that influence production. This study aims to determine the impact of inter-seasonal rainfall variability on rainfed rice yield in Collines. In order to achieve these purpose three objectives were considered; establishing the nature of spatial and temporal variation of inter-seasonal rainfall and rice yield, determining farmers‘ perception on agro-calendar and to determine the relationship between inter-seasonal rainfall and rainfed rice yield in districts of Collines. Different types of datasets were used; Secondary dataset - Tropical Rainfall Measuring Mission dataset calibrated (correlation coefficient r = 0.86) with in situ measurement of weather station of Save for the same period, data on annual yields and total rice growing acreage; Primary data of 100 rainfed rice farmers were randomly and purposively interviewed on rainfall season, rice growing season, constraints and factors affecting production. The primary and secondary data sets were transformed and subjected to descriptive statistics, correlation analysis and simple linear regression analysis to determine impacts of inter-seasonal rainfall over a time period 1998 to 2015. The results shows inter-seasonal rainfall is decreasing (coefficient of determination, r2 = 0.15) and rice yield is increasing (r2 = 0.18) within the six districts with coefficients of rice yield variability are; Bantè (0.22), Dassa-Zoumè (0.24), Savalou (0.21), Ouèssè (0.32), Glazoué (0.35) and Savè (0.36). Rainfed rice farmers responses (68%) of three districts (Bantè, Savalou and Glazoué) indicate rainfall and rice yield are decreasing within the districts and 100% blame a shift in agro-calendar onset. Finally inter-seasonal rainfall variability impacts varies differently from district to another but statistically significant for Ouèssè where 29.6 % of inter-seasonal rainfall variability are explaining rice yield variability in a district of Ouèssè, 70.4% remaining are attributed to other unexplained factors such as soil, farming methods, planting date, weeds, seed varieties, pest and diseases. The study concludes that the decreasing rate of inter-seasonal rainfall and impacts have not reached a critical level to induce significant impacts on the rice yields within districts of the Administrative Unit of Collines. The study recommends a need to invest in rainfed rice insurance scheme, rice farmers‘ capacity building on farming practices and the irrigation scheme for the Collines region in future.