ANALYSIS OF DRY SPELLS AND ITS APPLICATION TO CROP PLANNING IN THE SUDANO-SAHELIAN REGION OF NIGERIA

This study analyzed the sequences of dry and wet spells occurrence using the 1918-2004 rainfall data from the Sudano-Sahelian region in Nigeria (SSRN). It evaluates and uses the distribution and probabilities of the intra-season dry spell to describe how effective crop planning can be achieved in the midst of prevailing dry spells in SSRN. The approach adopted also involves the use of some other empirical computations to determine the risk level and percentage frequencies of dry spells for successive days after sowing (DAS) a crop. The results of the probabilities of maximum dry-spell length exceeding 7 to 15 days over the next 30-days helped to assess if the break of a dry spell due to rain has a significant impact on the subsequent spell length. The maximum dry spell length at five probability levels (risk levels) for different DAS and rainfall thresholds as well as the computation of the probable length of growing season provides estimates of appropriate time of sowing, type of crop to grow, and the cropping pattern to be adapted in the midst of the prevailing dry spell conditions in SSRN.