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

The general increase in annual rainfall may be due to the fact that, some years recorded very high rainfall which might have generally influenced the overall trend. For instance, from the graph the annual rainfall recorded in the area showed the following figure; 2003 (1406.8mm), 2007 (1595.7mm), 2009 (1595.7mm). This means that even though annual rainfall increase over the period, the rate of increase was gradual. The high recordings of rainfall in some periods of the years may be detrimental to crop production especially those which do not need excessive rainfall. It is also important to note that the high amount of rainfall in the area as observe by the study is related to temperature which invariably increase evapo transpiration rates. Figure 1: Annual rainfall trend in Nasarawa State Figure 2: Mean rainfall of Nasarawa State (2001-2015) 0 200 400 600 800 1000 1200 1400 1600 1800 Rainfall (mm) YEARS 0 20 40 60 80 100 120 140 rainfall (mm) YEARS 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 37 ( H ) © 2021 Global Journals Version I