Comparison of Weed Biomass and Flora in Four Cover Crops and a Subsequent Lettuce Crop on Three New England Organic Farms

Abstract

ABSTRACT Many vegetable growers in the northeastern United States routinely utilize cover crops to suppress weeds as well as conserve and enrich the soil. An exploratory study was conducted to compare weed biomass and species composition in four different cover cropping programs, and in lettuce grown after the cover crops were incorporated into the soil. The treatments were: two plantings of buckwheat followed by winter rye (BW/R), sudangrass followed by winter rye (SG/R), mammoth red clover + oats (C+O), and Italian ryegrass (RG). Cover crops were grown from spring 1988 through spring 1989, then followed by lettuce Some buckwheat plantings suppressed summer weeds effectively, but others failed because of drought. Sudangrass tolerated drought, but grew rapidly and outcompeted weeds only at the most fertile site. Clover established slowly, but suppressed weeds more effectively than rye during fall 1988 and spring 1989. Ryegrass completed its life cycle in early summer 1988 and did not reseed itself effecti...