Planting Season’s Rainfall Trends and Droughts in the Forest Belt of Nigeria
Abstract
The planting season for most food crops in the forest belt of Nigeria is mainly concentrated in the months of March and April. This paper, therefore, examined the planting season’s rainfall trends and droughts using five synoptic weather stations (Benin, Ondo, Warri, Port Harcourt and Calabar) in the forest belt of Nigeria. The planting season’s rainfall and rain-days covering between 1941 and 2012 were computed from the data for the months of March and April. The trends of the rainfall and rain-days were analyzed using simple linear regression, second order polynomial and correlation. The coefficient of variation was used to investigate rainfall and rain-days variability. Drought intensities in the planting season were computed as percentage deviation from the mean. The results, among others, revealed declining trends of the planting season’s rainfall in Warri, Port Harcourt, and Calabar, with regression coefficients of -0.71, -1.94 and -0.31 respectively, while Ondo and Benin showed increasing trends with regression coefficients of 0.17 and 0.11respectively. Warri,
Ondo, Port Harcourt and Calabar revealed decreasing trends of the planting season’s rain-days with -0.07, -0.09, -0.12 and -0.05 regression coefficients respectively while only Benin showed increasing trends with regression coefficients of 0.02. Port Harcourt and Calabar witnessed the highest and lowest magnitudes of rainfall and rain-days variability. The planting season’s drought intensities varied from slight to disastrous, but regardless of drought intensities, Port Harcourt was the worst hit while Ondo and Calabar were the least hit. The paper recommends irrigation during the planting season in the forest belt of Nigeria to reduce the incidences of poor germination and wilting. Drought tolerant crop varieties should be cultivated while rainfall prediction and extension services should be intensified to enable local farmers align planting of food crops with prevailing rainfall trends.
