Abstract

The objectives of this study were to investigate the trend in monthly and annual precipitation, minimum and maximum air temperature using the Mann-Kendall test and Sen’s slope estimator and to evaluate the impact of precipitation and temperature variability on crop yields in southern Togo using multiple regression analysis. Monthly precipitation and temperature for four weather stations were collected from 1970 to 2014. A non-significant increasing trend in annual precipitation (P>0.05) was noticed in Atakpamé, Lomé and Tabligbo, while Kouma-konda revealed a non-significant decreasing trend (P>0.05). During the growing season, July had the highest precipitation (208.7 mm) in Atakpamé, June had the highest precipitation in Lome (198.5 mm) and Tabligbo (158.7 mm). Amongst the locations, Kouma-konda has the highest monthly precipitation (226.2 mm) obtained in June. There was a significant increasing trend (P<0.0001) in Tmin and Tmax at all locations except in Kouma-konda where Tmax has decreased insignificantly. In Atakpame and Tabligbo, the precipitation and temperature have non-significant effect on the crop yields with very low coefficient of determination ranging from 0.024 to 0.107. In Kouma-konda, the increase of temperature has significant effect on maize and bean. Therefore, climate projection studies and adaptation strategies for agriculture are recommended for yield stability in locations where crops are affected by climatic variability.

Keywords: Trend analysis; Mann-Kendall test; Theil-Sen estimator; Multiple regression