Impact of Rainfall Variability on Yam (Dioscorea Spp) Yield in Lafia Local Government Area of Nasarawa State, Nigeria

Abstract

Rainfall variability influences almost all human endeavours, most especially in the field of business, health, transportation and tourism, and most importantly in the aspect of agriculture. Agriculture is the main activity engage by most developing countries even with the general threat to food security globally. This study centered on examining the impacts between rainfall variability and yam yield for the period of eleven years covering from 2006- 2016 in Lafia Local Government area. Eleven years (monthly/annual) rainfall data with annual yam yield data of Lafia Local Government were collected for the study. The analysis was carried out using E-Views 9 statistic for the trends and impacts analysis while Mann Kendall analytical approach was also used with the aid of Xl statistical software/tool for an in-depth regressing/coefficient of determinants analysis and variance of regression models analysis in the study. The result shows that rainfall variability has a significant impact of about 79% over yam production output (yield) and the remaining 21% is contributed by other factors than rainfall. The study also reveals a variability level of rainfall and yam output of Lafia at 10% and 37% coefficient of variance for a low and moderate extent of variability respectively. It was also concluded that there exists a strong positive impact of rainfall variability over yam-tuber output for the period under study. It is therefore recommended that other researchers and relevant bodies should carry an empirical study on the impacts of total land area for yam cultivation, soil fertility and socio-political factors to yam tuber production output (yield) in the study area.