Rainfall variability and drought during the sowing season and mid-season of rice in the Sudano-Sahelian Region of Nigeria

This paper examines rainfall variability and change as well as drought intensities in the Sudano-Sahelian region of Nigeria with a focus on the sowing season (June - July) and mid-season (August - October) of the farming calendar of rice. Monthly rainfall and rain-days data for Sokoto, Gusau, Katsina, Kano, Potiskum, Nguru, Maiduguri and Yola for 65 years (1951-2015) were sourced from the archives of the Nigerian Meteorological Agency. Rainfall decreased in Katsina and Nguru at annual rates of 0.69mm and 1.12mm respectively while it increased in Sokoto, Gusau, Kano, Potiskum, Maiduguri and Yola at annual rates of 0.39mm, 0.34mm, 03.77mm, 0.18mm and 0.37mm respectively during the sowing season. Rainfall decreased at annual rates of 1.38mm, 1.96mm, 0.57mm, 0.84mm, 0.71mm and 1.54mm in Sokoto, Katsina, Potiskum, Nguru, Maiduguri and Yola respectively while it increased at 2.31mm and 3.70mm in Gusau and Kano respectively. Rainfall changed significantly in Nguru during the sowing season and Sokoto Katsina, Kano, and Yola during the mid-season. Rain-days declined annually at the rate of 0.062, 0.049, 0.058, 0.042, 0.001, 0.083 and 0.070 in Sokoto, Gusau, Katsina, Kano, Potiskum, Nguru and Maiduguri respectively while it increased in Yola at 0.038 during the sowing season. It decreased at annual rates of 0.119, 0.120, 0.079, 0.052, 0.016, 0.006 and 0.316 in Sokoto, Gusau, Katsina, Kano, Potiskum, Nguru and Maiduguri respectively while it increased in Yola at 0.001 during the mid-season. Rain-days changed significantly in Potiskum, Nguru and Maiduguri during the sowing season while it changed significantly in Sokoto, Gusau,, Potiskum and Maiduguri during the mid-season. Generally, droughts were more of slight and moderate intensities with Sokoto having the highest percentages of severe and disastrous categories. Timely weather forecasts and irrigation practice in relation with the different phases during rice farming calendar as well as cultivation of improved varieties are recommended. Keywords: Drought, Mid-season, Rainfall, Rice, Sowing season, Sudano-Sahelian region, Nigeria