Agro-climatic zonation based on rainfall distribution over

Abstract

The study focuses on the agro-climatic zonation based on rainfall distribution patterns using ArcGIS for mapping; it also employed  frequency distribution to analyze rainfall data in Ondo State, Nigeria using rainfall data of 30 years’ period (1991 – 2020). The result  showed that rainfall amount is not a serious problem in plant growth in the humid tropics compare to the availability of soil moisture  which is a major factor. The results of seasonal distribution patterns in accordance with the seasonal method employed in this study shows that January and February (dry months) recorded rainfall ranged from 3 mm to about 27 mm; the rainfall recorded ranged from  about 95 mm to 130 mm in the months of March and April (Transition into wet season), while the recorded rainfall for the months of May  to July (Wet season I) is about 190 mm and 275 mm. The rainfall recorded in the month of August (little dry season) is between 166 mm  and about 208 mm. The rainfall data used in this study revealed month of August as little dry season contrary to results of some studies that shows that little dry season is now a July – August phenomenon, and not just August alone. The rainfall recorded ranged from about  203 mm to about 275 mm in the months of September and October (Wet season II), while that of November and December (Transition  into dry season) is between 11 mm and about 40 mm. Although several studies have speculated that climate change will make weather  and climate of some countries in Sub-Sahara Africa become unstable, the results show that little dry season popularly called “August  Break” is anomalous. It shows clearly from this study that rain-fed agriculture is most viable in between Transition to Wet Season and Wet  Season II. The recorded annual rainfall amounts ranged from about 1200 mm to 1600 mm in the northern side and between 1800  mm and about 2000 mm in the southern side of the study area. It is observed from the results of this study that rains do break after initial  rains. Therefore, it is important to advice farmers not to rush to plant crops such as maize with early rains because there is no assurance that the rains will not stop and this will lead to plants wither before steady rains.