Weeds are a top management concern among organic vegetable growers. Abrasive weeding is a nonchemical tactic using air-propelled abrasive grit to destroy weed seedlings within crop rows. Many grit types are effective, but if organic fertilizers are used, this could integrate weed and nutrient management in a single field pass. Our objective was to quantify the effects of abrasive grit and mulch type on weed suppression, disease severity, soil nitrogen availability, and yield of pepper (Capsicum annuum L. ‘Carmen’). A 2-year experiment was conducted in organic red sweet pepper at Urbana, IL, with four replicates of five abrasive grit treatments (walnut shell grits, soybean meal fertilizer, composted turkey litter fertilizer, a weedy control, and a weed-free control) and four mulch treatments (straw mulch, bioplastic film, polyethylene plastic film, and a bare soil control). Abrasive weeding, regardless of grit type, paired with bioplastic or polyethylene plastic mulch reduced in-row weed density (67 and 87%, respectively) and biomass (81 and 84%); however there was no significant benefit when paired with straw mulch or bare ground. Despite the addition of 6 to 34 kg N/ha/yr through the application of soybean meal and composted turkey litter grits, simulated plant N uptake was most influenced by mulch composition (e.g., plastic vs. straw) and weed abundance. Nitrogen immobilization in straw mulch plots reduced leaf greenness, plant height, and yield. Bacterial spot (Xanthomonas campestris pv. Vesicatoria) was confirmed on peppers in both years, but abrasive weeding did not increase severity of the disease. Pepper yield was always greatest in the weed-free control and lowest in straw mulch and bare soil, but the combination of abrasive weeding (regardless of grit type) and bioplastic or polyethylene plastic mulch increased marketable yield by 47% and 21%, respectively, compared with the weedy control. Overall, results demonstrate that when abrasive weeding is paired with bioplastic or polyethylene mulch, growers can concurrently suppress weeds and increase crop N uptake for greater yields.
Emily E. Braun, Sarah Taylor Lovell, Mohammad Babadoost, Frank Forcella, Sharon Clay, Daniel Humburg and Sam E. Wortman
Michael R. Evans, Andrew K. Koeser, Guihong Bi, Susmitha Nambuthiri, Robert Geneve, Sarah Taylor Lovell and J. Ryan Stewart
Nine commercially available biocontainers and a plastic control were evaluated at Fayetteville, AR, and Crystal Springs, MS, to determine the irrigation interval and total water required to grow a crop of ‘Cooler Grape’ vinca (Catharanthus roseus) with or without the use of plastic shuttle trays. Additionally, the rate at which water passed through the container wall of each container was assessed with or without the use of a shuttle tray. Slotted rice hull, coconut fiber, peat, wood fiber, dairy manure, and straw containers were constructed with water-permeable materials or had openings in the container sidewall. Such properties increased the rate of water loss compared with more impermeable bioplastic, solid rice hull, and plastic containers. This higher rate of water loss resulted in most of the biocontainers having a shorter irrigation interval and a higher water requirement than traditional plastic containers. Placing permeable biocontainers in plastic shuttle trays reduced water loss through the container walls. However, irrigation demand for these containers was still generally higher than that of the plastic control containers.