Title: Strategies for weed suppression and improving soil fertility during transition to organic vegetable production
Abstract: Farmers view weed management and the risk of lower yields as barriers to transition from conventional to organic agriculture. The 3 years of transition before organic certification can be used to implement strategies to suppress weeds and improve soil fertility. The objective of this research was to evaluate the effects of five organic transition strategies on soil quality, weed suppression, and yield of tomato (Solanum lycopersicum) and potato (Solanum tuberosum) in the first year of organic production. The transition strategies included a tilled fallow, nontreated weedy, high diversity prairie mixture, smother crops, and vegetable rotation. Subplots with and without compost application were also included. Transition strategies affected weed density and biomass in the first organic year with the prairie strategy being the most suppressive of monocotyledonous weeds before potato. Compost application increased plant available nutrients and soil organic matter (OM). The quantity of plant available phosphorus was greatest in the fallow transition strategy (55 mg·kg−1) when compost was applied, while percent soil OM was highest in the prairie (3.2%) and nontreated (3.1%) strategies in comparison with the other strategies. Compost application increased yields of potato and tomato with transition strategy affecting the number and weight of cull potato tubers. The selection of transition strategies before conversion to organic agriculture affected weed pressure, soil quality, and crop production in the first certified organic year. [Stephanie Wedryk, Joel Felix, Doug Doohan & John Cardina (2012). Strategies for weed suppression and improving soil fertility during transition to organic vegetable production. HortTechnology, 22(2), 207-214 ]