Year of Publication

2006

Document Type

Thesis

College

Agriculture

Department

Plant and Soil Science

First Advisor

Mark Williams

Abstract

Two field studies examining direct ecological weed control practices were conducted in Lexington, Kentucky. The first evaluated weed control efficacy and influence on yields of several mulches in two organically-managed bell pepper (Capsicum annum) production systems for two years. Peppers were planted in double rows in flat, bare ground or on black polyethylene-covered raised beds with drip irrigation, and four mulches (straw, compost, wood chips, and undersown white dutch clover (Trifolium repens L.) living mulch) were applied to the two production systems. In both years, polyethylene-covered raised beds produced higher yields than the flat, bare ground system. In the second year, the polyethylene-covered bed system coupled with mulching in-between beds with compost or wood chips after cultivation provided excellent weed control and yields. The second field study evaluated the efficacy of soil solarization and shallow cultivation on the invasive and noxious weed johnsongrass over two years (Sorghum halapense). A soil solarization treatment, using clear plastic stretched over soil for eight weeks, and a cultivated bare fallow treatment, utilizing a tractor pulled cultivator implement equipped with sweep blades, were randomly applied during the summers of 2003 and 2004 to a field infested with johnsongrass. Solarized and cultivated plots in both years were lightly tilled 8 months after completion of the initial treatment period. At the conclusion of the experiment the johnsongrass population was significantly reduced in all treatments and in the control plots compared to the original infestation. These two experiments testing direct weed control practices (mulching, cultivation, solarization) were undertaken in the context of an ecological weed management plan that includes long term strategies to reduce weed infestations such as crop rotation, cover cropping, and fertility management that are essential for organic farmers.

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