Global Journal of Science Frontier Research, H: Environment & Earth Science, Volume 21 Issue 6

and a high or maximum temperature in order to be balanced and produce high yield of crops (yam). Note that too much rainfall and minimum temperature can cause the decay of yams as well as seeds on the farm. a) Test of Hypothesis We reject the Null hypothesis and accept the alternative hypothesis from the above it was found that there was a weak positive relationship between rainfall, temperature and yam yield in Nasarawa state. Hence, the Null hypothesis was rejected and the alternative hypothesis accepted. H 0 : Null hypothesis rejected H 1 : Alternative hypothesis accepted b) Effect of Rainfall and Temperature on Yam Yield in Nasarawa State To assess the effect of some of the climatic variables (rainfall and temperature) on crops (yam yield) linear regression analysis was used to investigate the ability of the two climatic variables (rainfall and temperature) to predict yam yield. Table 6: Coefficients Model Unstandardized coefficients Standardized coefficients t Sig. B Std. Error Beta (Constant) -27.411 30.049 -.912 .381 Rainfall .001 .005 .075 .279 .785 Max temperature .046 .057 .215 .799 .441 Min temperature .095 .057 .445 .662 .125 Table 6 show the effects of rainfall and temperature variations on yam yields in Nasarawa state for the period of 2001 to 2015. The table revealed that rainfall variation has a weak positive effect of (0.075) on yam production within the period investigate. The major variable responsible for huge variation in yam yield was minimum temperature, it had a highly positive significant relationship in the production of yam in the study area between 2001 and 2015. Table 6.6 shows the standardized coefficients Beta of 0.445 for minimum temperature as the highly weak positive significant relationship with a t’ value of 1.662 which is approximately 2.062. c) Relationship between Rainfall and Yam Yield in Nasarawa State d) Yam Yield V. C onclusion The study has established that, there is slight variability in rainfall which translates into variability in some year as indicated by the rainfall data in Lafia, Nasarawa state. Data were collected for a period of 15 years from the Nigeria Meteorological Agency (NIMET) and Nasarawa Agricultural Development Program (NADP), Lafia. The data also shows a steady increase in yam yield in the study area with an R 2 = 0.226 variance within the years under review (2001-2015). The results from the study showed a weak positive significant effect in rainfall with unreliable rainfall distribution over the investigated period (2001-2015). The study identified poor yield as a major negative effect of rainfall variability on yam yield, though a weak significant amount. The Analysis of Rainfall and Temperature Patterns on Yam Yield in Lafia, Nasarawa State, Nigeria 1 Global Journal of Science Frontier Research Volume XXI Issue VI Year 2021 4 ( H ) © 2021 Global Journals Version I Coefficients: that of the coefficients, the standardized coefficient beta for mini temperature is o.445, while the t= 1.662 which is approximately 2.062 so as you can see it’s a good one and it is very high. This means there is high production of yam (crops) with minimum temperature and rainfall. Figure 3 shows the yield over the period (2001- 2015) of Lafia, Nasarawa state with a steady increase, and 21.69 being the highest recorded of the trend annually which shows an increase in the yam yield in the study area; it also portrays a combination of factors favourable, which may have positive effect on yam yield example (temperature, soil, fertility, soil, porosity level and moisture content amongst others) this means that these factors at equal and favourable condition have a positive effect on yam yield, in the state. Therefore this support the study of Kalibbala (2011) who asserts that favourable climatic and nutrient value have a positive effect on yam yield. However we observed a decrease in yam yield in the wake of high soil temperature and pH of the soil. The relationship between rainfall and yam yield in Nasarawa state were examined using correlation analysis shown in table 4.5 and 4.6 the result of the analysis revealed that rainfall has the weakest positive significant relationship with yam yield in the study area. The implication of this is that the higher the rainfall and temperature, the higher the yield of yam. The possible reason for the fairly correlation between rainfall and yam production may also be attributed to nature of soil, fertility rate some times.