The effect of mid-late season weed management strategies in fresh market tomato production

John Ernest McMillan, Purdue University

Abstract

Midwestern tomato (Solanum lycopersicum L.) producers, who rely on a period threshold approach for in-season weed control, allow weeds that germinate after the period threshold to successfully complete their life cycle, thereby compounding weed problems in future rotations. Limited herbicide development for tomatoes and the need for alternative weed control strategies in organic agriculture leaves a crucial gap in information that must be filled for successful tomato production to continue in the Midwest. We assessed the potential use of late-season mowing and a cover crop (buckwheat, Fagopyrum esculentum Moench) planted after the period threshold between tomato rows to maintain or reduce weed seed bank size. Although buckwheat establishment was poor in 2007 and 2008, the weed seed bank was significantly smaller in buckwheat plots than in period threshold plots. Mowing between rows near the end of the growing season reduced the weed seed bank relative to the period threshold in 2007 but not in 2008. Mowing appears to have potential for limiting weed seed production but must be carefully calibrated with weed phenology. In a separate experiment, we determined the effect of buckwheat density (0, 56, 112, 168, and 224 kg/hectare of buckwheat) on weed densities and tomato growth. In both years of the experiment, weed densities decreased linearly or curvilinearly as buckwheat density increased. Early light interception was related to buckwheat density suggesting that the rate of canopy closure may be important in suppressing weeds. These studies suggest that substantial reductions in weed seed banks are possible if late emerging weeds are controlled.

Degree

M.S.

Advisors

Gibson, Purdue University.

Subject Area

Agronomy|Horticulture

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