An economic comparison of weed management systems used in small-scale organic vegetable production

Abstract

Weed management strategies likely provide trade-offs in economic implications. Farmers may prioritize weed control during the “critical period” of the crop and ignore subsequent weeds; they may focus on the long term by eliminating additions to the weed seedbank with a “zero seed rain” approach; or they may suppress weed emergence with polyethylene (PE) or hay mulch. We aimed to compare the economic trade-offs of these approaches by implementing each system in a test crop of yellow onion (Allium cepa L.). We found that the zero seed rain system required the most weeding labor and the most evenly spread workload, while the hay mulch system required the most concentrated workload, due to the task of mulching. Despite the labor costs of the zero seed rain and hay mulch systems, net farm income (NFI) was most sensitive to onion yield and these systems resulted in the greatest NFI. The hay mulch system represented the least economic risk, followed by the zero seed rain, PE mulch, and critical period systems, respectively. In a subsequent crop of sweet corn, NFI was decreased 2524 USD ha⁻¹ in plots where the critical period system had been implemented the previous year, likely due to increased weed competition. Overall, despite the long-term focus of the zero seed rain and hay mulch systems related to the weed seedbank and soil quality, respectively, these systems were most profitable in this short-term study.