Common Bean Response to Tillage Intensity and Weed Control Strategies

Increased concern about environmental degradation, reduced biodiversity, and high production costs for common bean ( Phaseolus vulgaris L.) in Nicaragua have increased farmers’ interest in reduced or no tillage systems in combination with low cost and environmentally friendly weed management. This study examined how tillage and weed control measures affect weed densities and biomass, common bean yield, and net income. Three tillage treatments [no tillage (NT), minimum tillage (MT), and conventional tillage (CT)] and three methods of weed control (mulching, mechanical, and chemical) were evaluated in the same field for 3 yr (1994–1996). Bean canopy height was measured twice during the growing season, and bean yield components were recorded each year. Weed biomass and weed density of monocots and dicots, respectively, were measured 28 and 42 days after sowing (DAS) in each experiment. There was an interaction between years and weed control for both weed density and weed biomass. There was also an interaction between tillage system and weed control system regarding bean yield and net economic benefit. Minimum tillage outyielded NT and CT by 10 and 15% and resulted in an increase in net income that was 23 and 35% greater than NT and CT, respectively. Mechanical and chemical weed control increased yields more than mulching in NT and MT. Mechanical weed control with NT or MT would be sufficient to ensure profitable production of common bean. This practice should be combined with the use of both weeds and preceding crop residues as mulches.