Evaluation of Alternative Break Crops in Rotation with Bread Wheat (triticum aestivum l.) in South-Eastern Ethiopia

Crop rotation could be a possible intervention to resolve multifaceted problems of monoculture. In recent years, there is a concern about soil depletion caused by intensive farming. In crop rotation legume crops, which capture atmospheric nitrogen and “fix” it into forms available to plants will increase soil fertility. Faba bean (Vicia faba L.), rapeseed (Brassica napus L.), oat (Avena sativum L.) and vicia (Vicia dasycarpa Ten.) forage mixture were considered as a break/precursor crops. The result showed that most profitable cropping sequence was faba bean grown in a 3 year cycle with 2 crops of wheat (Amanuel et al., 1994). Thus, searching for promising and alternative break crops for wheat based rotation could increase productivity and maximize profit. Adaptaion trial around Bekoji showed that sweet lupine seems an option in tolerating acidity where faba bean is found susceptible. Thus, the objectives of this study was to evaluate alternative break crops on yield and yield components of the succeeding wheat and soil fertility maintenance in the rotation scheme. Thus, this study was executed for three consecutive years from 2017- 2019 main cropping seasons at Kulumsa, Bekoji and Asasa Arsi zone, South-Eastern Ethiopia to evaluate advantage of alternative break crops on yield and yield components of the succeeding wheat and its effect on soil fertility maintenance in the rotation scheme. The experiment was laid out in randomized block design with five replications. The treatment include: wheat-sweet lupine-wheat-wheat-wheat in year one (2017), sweet lupine-wheat-wheat faba bean-Ethiopian mustard in year two (2018) and wheat-wheat-wheat-wheat-wheat in the third year (2019). These leguminous crops have improved physico-chemical properties of soil. Plant nutrients of soil on which legumes were grown were increased. This improvement of soil properties by leguminous crops has resulted in higher yield of wheat than plots on which wheat was grown after wheat. Although non-significant, the third year Bekoji and Asasa combined analysis of variance revealed that the highest wheat grain yield (4197kg/ha) was obtained at sweet lupine-wheat-wheat followed by wheat-faba bean-wheat (4003kg/ha). However, plant height was significantly (P<0.05) affected by rotational crops effect. The tallest plant height of wheat (105.0cm) was recoded from wheat-Ethioian mustard-wheat treatment. From this study, sweet lupine-wheat-wheat followed by wheat-faba bean-wheat with proper agronomic packages could be forwarded as a temporary recommendation in Asasa, Bokoji and Kulumsa areas and in areas with similar agro ecologies.