Effect of Cassava Intercropping with Legume Crops Followed by Sorghum on Growth, Yield and Yield Parameters of Cassava-Based Double Cropping System

Abstract

Some lowland farmers of eastern Harerghe survive with some grain support from government and different NGOs due to shortage of rainfall and prevalence of drought. In Harerghe, intercropping is well practiced and most of farmers intercrop Khat with sorghum and groundnut, but single production per year. To these gaps the experiment was proposed and conducted under rainfed conditions at Fedis Agricultural Research Center of Oromia Agricultural Research Institute (OARI) at Boko sub-site, eastern Ethiopia to determine the compatibility of crops in double cropping system and efficient land use for the component crops. Experimental was conducted in two phases: cassava (Variety Kello) with legumes (soybean, haricot bean and cowpea) and cassava based sorghum varieties (Hormat, Gedo and Birhan) in one cropping season. The treatments were arranged as intercropping and sole cropping. A total of 7 treatments for preceding and 7 treatments for cassava-based succeeding treatments were arranged in completely randomized block design with three replications. Variety Kello was used for the experiment. The results revealed that there were significant (P<0.05) differences for cassava average root weight, number of roots per plant, root diameter and root yield due to cassava-legumes intercropping. Soybean-cassava intercropping increased average root weight, root numbers and root enlargement of cassava by 39, 33.6 and 27.7% as compared to cassava-cowpea intercropping. Cowpea intercropping in cassava was significantly affected cassava root yield as compared to other legumes intercrop. Cassava-soybean intercropping was increased root yield by 41.7 and 21.3% as compared to cassava-cowpea and cassava-haricot bean, respectively. Cassava-soybean intercropping improved land use efficiency by 16.4 and 19.3% as compared to cassava-cowpea and cassava-haricot bean intercropping, respectively. Accordingly, pure stands could required 74, 40 and 46% more land i.e. the mixture cropping gives 74, 40 and 46% yield advantage, for soybean, haricot bean and cowpea, respectively, as intercropped in cassava than the pure stand. Following the harvest of legumes, sorghum was sown as double crop for additional yield advantage. The highest organic matter and total nitrogen was recorded for the pure stand plot of cassava followed by cassava-soybean intercropping. Therefore, from this result view, cassava-soybean intercropping following cassava-based early maturing sorghum was recommended for the study area and similar agro ecologies.