Abstract:
Agroclimatological
information
provides the basic tool for proper and profitable
agricultural planning. The study was aimed at carrying out detailed analysis of rainfall data
of iong term duration in humid and subhumid stations in Nigeria using Onne and Ibadan
meteorological data.
Data were analysed to obtain general rainfall characteristics such as precipitation
index, distribution and variability of the two stations. The shortcoming of these methods led
to the development of further analysis of the rainfall data to obtain daily soil water budget
the falling rate soil water budget based on some reasonable assumption and this was used
to calculate daily water supply budget which was further analysed to obtain the runs of
consecutive days with wet soil thus enabling determination of time of sowing and
harvesting.
The rainfall data was modelled using the first order Markov chain to determine the
dependence of wet and dry days. The probability of a dry day following a dry day for Ibadan
varies between 0.44- 0.98 and 0.64- 0.99 for Onne. The study indicate that for the
purpose of agricultural planning in these zones, there is the need to take into account the
weather condition of at least two previous days in order to predict the occurrence of wet or
dry spell during the growing season.
Significant
reduction of about 20. days was recorded in the length of the growing
season over the period under study for both sites. Also a significant decline in rainfall total
.was observed particularly in Onne.
The result obtained would be useful for agricultural planning and mapping on
regional scale. It is equally adaptable to growing season determination
