Start, end and dry spells of the growing season in semi-arid southern Zimbabwe

Smallholder agriculture in semi-arid Zimbabwe is dependent on the seasonal characteristics of rainfall. The determination of start, end and length of the growing season, and the pattern of dry spells during the season is useful information for planning land preparation and planting activities. This study was designed to assess whether there has been any changes in the start, end and length of growing season and the pattern of 14 and 21 day dry spells during the season. Daily rainfall data were collected from five meteorological stations located in southern Zimbabwe. Results indicated that no significant changes in the start, end and subsequent length of growing season occurred over the past 50-74 years. There was no significant change in the number of wet days per season over the period reviewed. There is a high probability of 14 and 21 day dry spells during the peak rainfall months. The relationship between start and end of growing season is stronger as aridity increases. We conclude that growing seasons have not changed significantly over the past 50-74 years in southern Zimbabwe. As smallholder agriculture continues to be affected by dry spells and droughts, there is scope in exploring rainwater management technologies in rainfed cropping systems. (C) 2011 Elsevier Ltd. All rights reserved.