Influence Of Inter-Annual Rainfall Variability On Yam Yield In Lafia LGA Of Nasarawa State.

ABSTRACT

This study soughUt the influence of inter-annual rainfall variability on yam yield in Lafia LGA of N 2te. The following objectives were set in order to achieve the aim; to determ i ne the railility in the study area, to determine the yam yield trend in the study area and to dete~elationship between rainfall variability and yam yield trend in the study area_ YarrVortant crop in the study area and the changing pattern of rainfall necessitated the ie study. Secondary source of data collection was employed to get rainfall and ya1ata for eleven (11) years. They were collected from Nigeria Meteorological JMET) substation in Lafia and Nasarawa Agricultural Development Progl-arn.med (N~ctively. Yam yield was gotten from the 27,627 registered farmers in Lafia L_G_A." 1:ht measure as 1000 killogram is equal to Itonnes. Thus the total yield was r-ecorded asnes. While rain-gauge was used to collect and measure the amount of rainfall ina day no rainfall at all it was recorded as O.OOmm, while rain fall that cannot be read Vv'as rec·ace. The data collected were subjected to various statistical analysis whic h inc Iud e 4 of variation, time series analysis, kurtosis, skewness and regression analys i s_ The clf variation of rainfall for the years under study was round out to be 14.300/0 Vv'h ich i the inter-annual rainfall variability in the study area is not high. It was also d i scoverednfall distribution is normal since the mean of 1257 _5mrn is higher than 750rYlm _ Kurto:wness of rainfall for growing season was accepted as indicative of normal i ty at 9.:ant level because all the calculated value are below 1.98. Time series anal ys is Vv'as cain fall distribution of the growing season months of the years under study." on I y thtf April and August shows a negative trend line wh i Ie the months of May" J LI II e", J Liller and October all show a positive trend line. Downvvard trend in the month of Apperved to affect yield of yam because that: 1S the month of active germination ojethenegativetrendinAugustwillalsogive a low yield because in that month yarn. isg active tuberization and leafs Regression analysis 'vvas done on the rain fall data a:ld. It was discovered that rainfall has significant influence (3668.2) at 5% on yam yiiudyarea. The result thus implies that the variabil it)' of rainfall will infl uence yarne study area.