Abiye Astatke¹, S.C. Jutzi¹ and M. Grunder²
1. Highlands Programme, International Livestock Centre for Africa (ILCA), PO Box 5689, Addis Ababa, Ethiopia2. Soil Conservation Research Project (SCRP) Community Forestry and Soil Conservation Development Department, Ministry of Agriculture, Addis Ababa, Ethiopia
Vertisols are potentially fertile soils occurring mainly on gentle slopes (less than 8%). If appropriate surface drainage is implemented in high rainfall areas, grain and straw yields can be increased over those obtained by traditional cultivation. The broadbed-and-furrow (BBF) system can be constructed using a low-cost animal-drawn implement developed from the traditional Ethiopian ard (maresha). The impact of surface drainage on soil and nutrient losses needs to be investigated to assess and recommend the optimum slope and furrow length for the technology.
A 1986 study found that the surface soil on broadbeds was significantly drier, and the daytime soil temperature higher, compared to the traditional system. No significant difference was observed in 1986 between the mean grain and straw yields obtained on BBFs and on the traditional system. The mean on BBFs, however, was higher and more consistent within the replications than on the traditional system. Low rainfall during the main growing period contributed to higher grain and straw yields on the traditional system than in previous years due to limited waterlogging. Soil and nutrient losses were minimal for the same reason and no significant differences were found between the two systems.
