Published online by Cambridge University Press: 03 October 2008
The effects of rainfall on yield of rainfed grain sorghum in a rotation experiment have been investigated over six years. There was a positive association between yield and rainfall during May and from the beginning of July to the first half of September, but a negative association at other times of the year. Total rainfall in August and September, and the annual total, were positively related to yield, while the totals of June and July were inversely related. Variation in monthly rainfall accounted for up to 86 per cent of the variation in yield, while the total rainfall in August and September accounted for up to 96 per cent.