Effects of stubble management, tillage and cropping sequence on wheat production in the south-eastern highlands of Ethiopia

Bread wheat (Triticum aestivum) yields are often low on peasant farmers’ fields in Ethiopia due to the use of sub-optimal crop management practices. Four multi-factor crop management trials were initiated during 1992 in the south-eastern highlands of Ethiopia. Two of the trials were based on mechanized tillage using disc plow, while two trials were based on the traditional ox-plow of Ethiopia. The four long-term trials examined the effects of alternative practices for crop residue management, tillage and cropping sequence (CS) on wheat grain yield and the severity of infestation by the grass weed Bromus pectinatus. Among the crop residue management treatments, stubble burning tended to increase the grain yield of wheat and decrease the severity of Bromus infestation in contrast to partial removal and complete retention of stubble. Conventional tillage tended to increase wheat grain yield and decrease Bromus severity in contrast to minimum and zero tillage. Faba bean (Vicia faba) included in a faba bean–wheat–wheat CS markedly increased wheat yields and reduced Bromus severity, particularly in the first wheat crop following faba bean. Significant factor interactions indicated that the severity of B. pectinatus infestation in wheat crops produced under reduced tillage systems could be minimized by burning of crop stubble and by adopting crop rotation with faba bean.