Soil tillage and crop productivity on a Vertisol in Ethiopian highlands Teklu Erkossa * , Karl Stahr, Thomas Gaiser Universita ¨t Hohenheim, Institute of Soil Science and Land Evaluation (310), Postfach 70 05 62, D-70593 Stuttgart, Germany Received 28 May 2004; received in revised form 12 January 2005; accepted 18 January 2005 Abstract Soil quality deterioration and consequent reduced productivity characterize the Vertisols in the highlands of Ethiopia. The problem is exacerbated by lack of appropriate land preparation alternatives for the major crops in the area. A field experiment was carried out for 6 years (1998–2003) at Caffee Doonsa in the central highlands of Ethiopia to evaluate alternative land preparation methods on the performance of wheat (Triticum durum Desf.), lentil (Lens culinaries Medik L) and tef (Eragrostis tef L) grown in rotation. Four methods of land preparation (broad bed and furrow, green manure, ridge and furrow and reduced tillage) were arranged in a randomized complete block design with three replications on permanent plots of 22 m by 6 m. Broad bed and furrow significantly increased the grain yield of lentils by 59% (from 1029 to 1632 kg ha 1 ) as compared to the control. On the other hand, reduced tillage resulted in the highest grain yield of wheat (1862 kg ha 1 ) and tef (1378 kg ha 1 ) as compared to 1698 kg ha 1 of wheat and 1274 kg ha 1 of tef for the control although the increase was not statistically significant. A gross margin analysis showed that BBF is the most profitable option for lentil with 65% increase in total gross margin. On the other hand, RT resulted in 11 and 8% increase in gross margin of wheat and tef, respectively as compared to the control. Based on the agronomic and economic performances best combinations of crop and land preparation method were: lentil sown on broad bed and furrow, and wheat and tef sown after reduced tillage. # 2005 Elsevier B.V. All rights reserved. Keywords: Broad bed and furrow; Green manure; Reduced tillage; Ridge and furrows; Vertisol 1. Introduction In the central highlands of Ethiopia, where Vertisols cover 7.6 million hectares, crop production is highly constrained by the soil physical and hydrological properties. Land preparation is con- strained by the hardness of the soils when dry and their stickiness when wet. They have very slow internal drainage with infiltration rates between 2.5 and 6.0 cm day 1 (Teklu et al., 2004). The Vertisols in the area are diverse and occur under various climatic conditions. Although Chromic Vertisols are abundant, www.elsevier.com/locate/still Soil & Tillage Research 85 (2006) 200–211 * Corresponding author. Tel.: +49 711 459 2125; fax: +49 711 459 2124. E-mail address: erkossa@yahoo.com (T. Erkossa). 0167-1987/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.still.2005.01.009