Nitrogen fixation by common bean (Phaseolus vulgaris L.) in pure and mixed stands in semi-arid south-east Kenya

Abstract

Research was carried out in the field on the effect of intercropping common bean and maize crops in a semi-arid zone of south-east Kenya over two rainy seasons in 1997. The experimental design was a randomised complete block design with eight treatments replicated four times. Significant differences were observed in total plant dry weight by the different treatments in pure stands, 21 days after emergence with higher values under mixed cropping system in common beans. However, at 42 days after emergence, plant dry weights in uninoculated common bean pure stands with N application were significantly higher than under other treatments. Common bean yields were significantly reduced by the maize intercrop. The inoculated common bean and N application treatment recorded the largest seed dry weights and subsequently yields per hectare. These findings suggest that intercropping common beans and maize considerably suppresses the yield of the former under the semi-arid conditions of south-east Kenya. Inoculation of common bean with the commercially available Rhizobium strain 446 on the other hand was effective and improved yields. Soil analysis of the experimental plots before and after one cropping season indicated that common beans increased N slightly or maintained it at the pre-planting levels. This was unlike the pure maize plots where there was a marked decline in soil N. There was however, a marked increase in soil phosphorus in all treatment plots.

Effects of Rhizobium inoculation and cropping systems on macronutrients uptake and partitioning in two legumes (Common bean and Lablab)

“…Greater plant nutrient requirement during the N 2 fixation by legumes such as P. vulgaris and L. purpureus has similarly necessitated greater uptake of such macronutrients from the rhizosphere to the plant. The presence of small amount of macronutrients uptake in plots with no Rhizobium inoculation in this study indicated the existence of native Rhizobium strains in the soil that were effective in fixing N as also reported by (Maingi et al, 2001).…”

<b>Nitrogen management effects on soil mineral nitrogen, plant nutrition and yield of super early cycle common bean genotypes

“…Therefore, the crop is less subjected to insect attacks, diseases and weeds. Producing more food in less time is very important for many developing countries, such as those in Asia, the Americas and in Eastern and Southern Africa, where the crop in part of the daily human diet (Maingi, Shisanya, Gitonga, & Hormetz, 2001; Rosales-Serna, Kohashi-Shibata, Acosta-Gallegos, Trejo-López, & Kelly, 2004 In common bean production, nitrogen (N) is the most required nutrient and is one of the most limiting nutrients for the majority of agricultural crops (Nascente, Kluthcouski, Crusciol, Cobucci, & Oliveira, 2011). According to the conventional recommendation for irrigated common bean crops, top-dressed N fertilization normally consists of one N application (90 kg ha -1 ) at the growth stage V 4 (third trifoliate) (Barbosa Filho, Cobucci, & Mendes, 2005).…”

Finger millet and horsegram intercropping systems in replacement series for advantages and weed smothering

“…Effective nodules are the sites of symbiotic nitrogen fixation. Higher number of effective nodules under intercropping system over pure stand of legume is an indication that more atmospheric nitrogen fixation in the crop mixture (Maingi et al, 2001). So, more nitrogen fixation may be due to more numbers of nodule formations (Thompson, 1977).…”

“…Legumes, with their adaptability to different cropping patterns and their ability to fix nitrogen, may offer opportunities to sustain increased productivity (Jeyabal and Kuppuswamy, 2001). Therefore, productivity normally is potentially enhanced by the inclusion of a legume in a cropping system (Maingi et al, 2001). Legume intercrops are also potential sources of plant nutrients that complement/ supplement inorganic fertilizers (Banik and Bagchi, 1994;Ofori and Stern, 1987).…”