Comparing Weed Barrier Options for Organic Pepper Production

Surveys of 150 growers in western North Carolina indicated that weeds are a major limitation to profitability in organic crop production.  Nationally, weed management is considered a top priority for organic research. There are few effective weed control options for organic vegetables and questions arise as to which method is the most economical and which has the lowest labor requirements.  The objective of this study was to compare the use of several weed management practices in production of organic bell peppers (Capsicum annuum).  Material costs, labor needed to keep the plots weed-free, costs of implementing those practices, and yield, were measured.  Plants were grown on raised beds with drip-irrigation.  Practices and products used were in accordance with the National Organic Program standards.  Treatments included black landscape fabric, wheat straw mulch, white and red clover living cover crop sown at time of transplanting, black plastic mulch, and a bare ground control.  A hoe was used to weed the bare ground treatment.  Weeds were hand pulled in the other treatments.  There were four replications of the five treatments arranged in a randomized complete block design.  The study was conducted at the Mountain Research Station in Waynesville, NC.  In the first year of the study, 86% less labor was required to keep the landscape fabric and black plastic mulch treatments weed-free compared to the other three treatments.  The straw, living mulch, and bare ground treatments required the same amount of labor to be kept weed-free.  Although there was no difference in total yields among the weed management treatments, the living mulch treatment produced fewer U.S. Fancy grade peppers and more U.S. No. 1 grade peppers than the other four treatments.  Just comparing materials used for the weed barrier treatments, wheat straw was the most expensive and the living mulch was the least expensive. Taking all factors into consideration, the landscape fabric and black plastic were the most profitable weed management strategies.  This study will be repeated in 2011, and data from both years will be presented.