Agronomic management options to enhance adoption of maize–common bean–common bean sequential intercropping in southern Ethiopia

Abstract

Achieving food security is a prime strategic goal for many developing countries where subsistence smallholder farming is dominant. It is crucial to study and improve existing cropping systems and develop novel ones for enhanced production and efficient resource use. Experiment was conducted to identify compatible density and spatial arrangement for first associated common bean (Phaseolus vulgaris L.) under maize (Zea mays L.)–common bean–common bean sequential intercropping. Factorial combination of four bean densities and three bean arrangements was tested in randomized complete block design. Greater maize yields were obtained from 25 and 50% bean densities and from single-row and within-row arrangements. Single-row arrangement at any bean density and low to moderate densities at any arrangement maintained maize performance. Density by arrangement interaction indicated that increasing bean density enhanced competitive ability and productivity of bean under double-row and within-row arrangements. Greater maize partial land equivalent ratio (LER) of 0.90 and 0.92 were obtained at lower densities of 25 and 50%, respectively, and at single-row arrangement (0.93). Interaction of density with arrangement on total LER showed that moderate densities either in single- or double-row arrangement gave higher intercrop advantages up to a maximum of 59%. Mean net benefit from intercropping exceeded those from sole maize by 30% and from bean–bean double sole crop by 16%. Net benefit among intercrops did not vary significantly and this would allow farmers to make choice depending on their crop priority and their resources such as farm size, labor and crop management techniques.