Proceedings of 'Review 'Workshop on Completed Research Activities of Crop Research

Abstract

Maize based mono cropping is one o f the main bottlenecks that highly affects soil fertility and productivity in maize growing areas, particularly in sub-humid areas o f western oromia. Maizelegume based intercropping systems are one o f the best practices to avert such problem o f monoculture while increasing the productivity vertically. In recognition o f this fact, an experiment was conducted fo r two consecutive years (2013 and 2014) at Bako and Billo Boshe research sites. Three maize varieties (BH 661. BH 546 and Gibe 2), two climbing bean (Tibe and Dandessu) and three time o f bean planting (same, 15 and 20 days after maize planting) were arranged in fa c to ria l combinations in randomized complete block design with three replications. The result revealed that maize varieties by time o f bean planting significantly influenced maize and bean y ie ld as well as nitrogen, phosphorus anil water use efficiencies. The highest significant maize y ie ld (9 t/ha) was obtained when common bean was planted with BH 661 variety o f maize simultaneously, and fo llow e d hv BH 546 planted with bean 20 days after maize planting. But. the lowest maize y ie ld was recorded when Gibe 2 was intercropped with the bean simultaneously. Bean y ie ld performance in BH 546 was significantly decreased as the func tion o f increasing from same date to 20 days after maize planting But. higher vield o fB H 546 and bean 4 were obtained when the bean was intercropped in the maize after 15 day’s o f maize planting. Maximum bean y ie ld was obtained when ink r< roppt d u nil Gibe 2 variety at each time o f bean t planting though the highest yie ld was recorded u 'hen intercropped at the same time, but 31% maize y ie ld reduction observed. Yield o f BH 546 and Gibe 2 was significantly reduced by 12% and 29%, respectively due to competition effect o f companion crops where as only 5% reduction was observed when BH 661 was used for intercropping compared to respective sole crops. The highest wafer, nitrogen and phosphorus during growing season were utilized when BH 661 variety o f maize was planted simultaneously with common bean, and maximum LER (1.53) was also observed. However, significantly lower nutrient use efficiency was recorded from Gibe 2 variety intercropped with bean varieties regardless o f time o f bean planting. Positive value o f agressivity index o f maize showed that maize varieties except Gibe 2 intercropped simultaneously with bean were the dominant crops in mien ropping systems. In contrast, the negative agressivity value bean indicated climbing bean was significantly dominated by maize varieties except Gibe 2 variety when planted with the bean simultaneously. The highest net benefit (38808 ETB/ha) and more marginal rate o f return (MRR) could also be obtained when climbing bean was intercropped simultaneously with BH 661 variety o f maize. Even though intercropping o f bean at the same time with BH 546 variety gave the next highest net benefit, considerably more than 19% y ie ld o f the mam crop was reduced due to competition effect compared to its sole crop and hence is not advisable to the farmers since they mainly fo c u s fo r yield o f maize. However, intercropping o f bean 15 days after planting o f BH 546 variety could earn 33883 ETB ha'1 o f net benefit without significant reduction o f main y ie ld and hence fanners may prefer to use this practice in areas where there is scarcity o f BH 661 variety. In spite o f Us higher net benefit. Gibe 2 variety intercropped simultaneously with bean due to the highest bean yield performance, more than 31% yie ld reduction o f the main crop was observed. But. intercropping o f bean after 20 or more days o f maize planting o f Gibe 2 variety could be used to idvise the farmers as another option in areas where there is limited access to hybrid maize arieties to be used for intercropping.