Analysis of maize–common bean intercrops in semi-arid Kenya

Abstract

S U M M A R YMaize (Zea mays L.) and common bean (Phaseolus vulgaris L.) were each sown at four plant densities, including zero, in a bivariate factorial design at Kiboko Rangeland Research Station, Kenya during the long and short rains of 1990. The design gave nine intercrops with different proportions of maize and beans, and six sole crops, three of maize and three of beans. Seed yields in both the sole crops were not significantly affected by plant density, so the mean yield was used to calculate the Land Equivalent Ratio (LER), which averaged 109 in the long rains but only 0-87 in the short rains. These low values were apparently due to the fact that beans failed to nodulate and fix nitrogen in the study area. The difference in LER between seasons was probably caused by differences in the amount and distribution of rain in relation to crop growth. Maize was more competitive than bean, each maize plant being equivalent to between 0-7 and 3-4 bean plants depending upon the treatment and the season.

As the level of crop productivity increases: Is there a role for intercropping in smallholder agriculture

“…For example, in field experiments conducted under different rainfall locations in Ethiopia, intercrops produced 40% (LER = 1.40) and 10% (LER = 1.10) relative yield benefit per unit area than sole crops under 541 mm and 763 mm annual rainfall, respectively (Belay et al, 2009). Similar finding were reported for maize-bean intercrops in semi-arid Kenya (Pilbeam et al, 1994), when grown during the short and long rain seasons within the same year. In-crop rainfall during the short rainy season was higher (257.6 mm) than during the long rainy season (179.5 mm).…”

“…The amount of water applied to Experiment 1 (200-300 mm), Experiment 2 (300-400 mm) and Experiment 3 (over 400 mm) were chosen to represent semi-arid and sub-humid environments (Natarajan and Willey, 1986;Willey, 1990;Pilbeam et al, 1994;Belay et al, 2009;Echarte et al, 2011). T-tape drip irrigation was used to control soil water supply (340 L h −1 discharging rate within 100 m) to each experiment.…”

“…Reports on maize (Zea mays L) haricot bean (Phaseolus vulgaris L)/soybean (Glycine max L) intercrops (Pilbeam et al, 1994;Tsubo et al, 2004;Ogindo and Walker, 2005;Vahdettin et al, 2006;Ouda et al, 2007;Belay et al, 2009;Echarte et al, 2011) show that, in general, intercropped crops have higher LER values under low productivity environments, i.e. in water limited conditions.…”

“…N and water) factors, photosynthetically active radiation (PAR, 0.4-0.7 m wavelength) is the most important resource for crop growth and development in intercropping systems with crops of different heights (Watiki et al, 1993). Several studies indicate improved radiation interception and utilization in intercrops compared to sole crops (Reddy and Willey, 1981;Natarajan and Willey, 1986;Pilbeam et al, 1994;Szumigalski and Van Acker, 2008;Gao et al, 2010). However, the opposite was also observed (Zhang et al, 2008).…”

Relative competitive abilities and productivity in Ginkgo and broad bean and wheat mixtures in southern China

“…Although niche is defined in a number of different ways by ecologists, competition and the concept of niche differentiation are key themes of research on crop mixtures (Putnam et al 1985;Pilbeam et al 1994Pilbeam et al , 1995Siame et al 1997). Spatial and/or temporal offsets in the utilization of environmental resources may reduce competition in mixed species associations compared to pure stands (Veresoglou and Fitter 1984;Ong et al 1996), which may allow for greater productivity (Spitters 1983;Chui and Shibles 1984;Ofori and Stern 1987).…”