Effect of Mulching as a Weed Management Strategy in Field Production of French Beans (Phaseolus vulgaris L) in Western Kenya

There has been a 2% decrease on French bean (Phaseolus vulgaris L) production in Kenya due to factors such as weeds, pests and diseases and the challenge of controlling them using chemicals that result in high rejection rate or interception in the export market because of chemical residues. The objectives of this study were to evaluate the effect of different mulching materials on the growth and yield of French bean cultivars and to determine the effect of different mulching materials on weed density. Field experiments were carried out at KALRO Kitale, Trans Nzoia county Kenya. Season 1 was carried out during long rains of April and June 2021 and season two during the short rains of August and October 2021. Black polythene and grass mulch were compared with two hand weedings and no weeding in a Randomized Complete Block Design experiment with three replications. Data on growth and yield of French Beans were collected and subjected to ANOVA using GenStat to determine the significant differences between the treatments. The means were separated using Fisher’s Unprotected LSD at 5% significance level. Growth and yield of French Beans was significantly influenced by the treatments (p≤0.05). Plants grown under black polythene and grass mulch had the tallest height and the highest number of leaves and branches as well as number of pods and cumulative pod yield as compared to those that were hand weeded and unweeded. The highest yield of 2138 and 2597 kg/ ha was obtained under black polythene mulch in season 1 and 2 respectively. This was significantly higher than that obtained from grass mulch, hand weeding and unweeding. In conclusion polythene and grass mulch improved growth and yield of French beans and reduced weed density. It is therefore recommended that farmers should adapt mulching as a cultural weed management strategy.