Response of maize and common bean to spatial and temporal differentiation in maize-common bean intercropping.

An experiment on maize (Zea mays)-common bean (Phaseolus vulgaris L.) intercropping was conducted for two years (2014 and 2016) at two locations in North western Ethiopia with the objective of determining the spatial arrangement and planting date of common bean. Common bean intercropped with maize at three planting dates (simultaneously with maize, at emergence and knee height of maize) in two spatial arrangements (alternate and paired arrangements).The experimental design was factotrial randomized complete block design with three replications. Sole maize and common bean were included as a check. Results revealed that the spatial and temporal differentiation significantly affect only the agronomic attributes of common bean in common bean-maize intercropping. At Adet the grain yield of common bean (1.9 t ha-1), LER (1.99) and MAI (357) in maize-common bean intercropping was higher when common bean was planted at the same time with maize in paired planting pattern. On the other hand, maximum LER (1.61) and MAI (2.83) at Finoteselam were observed when common bean was intercropped with maize at maize emergence in paired planting pattern. Simultaneous intercropping of common bean with maize gave more stable total land output yield as compared to other intercropping systems but showed high variability as compared to the sole cropping. Thus, it can be concluded that planting common bean simultaneously with maize in paired planting pattern at Adet and planting common bean at maize emergence at Finoteselam in maize-common bean intercropping gave maximum land use efficiency and profitability of the cropping system without reducing the main crop yield (maize).This research also suggested further research on the compatibility of various maize and common bean varieties in different spatial and temporal differentiation.