Silage tarping for stale seedbed, early-season weed management, and cover crop termination

Small-scale farms in the U.S. face challenges in managing weeds within diverse cropping systems. The use of silage tarps by farmers has increased recently; however, little research is available that evaluates them. Silage tarping involves covering the soil with opaque plastic to block light for extended periods to keep fields weed-free early in the season, create stale seed beds, and terminate cover crops. To address this, different experiments were conducted to assess their effectiveness for (1) creating a stale seedbed in combination with S-metolachlor and hand-weeding in onion production, (2) early-season weed management in small-scale potato production, and (3) cowpea cover crop termination in combination with roller-crimping and mowing. (1) In 2023 and 2024, an experiment was conducted at the Purdue Student Farm in West Lafayette, IN to estimate the effectiveness of silage tarps, S-metolachlor, and hand-weeding for weed control in onions. The experiment tested tarping (tarped vs. non-tarped) and S-metolachlor (1,064 g ai ha⁻¹) application (once or twice) with or without hand-weeding. Tarping reduced early-season broadleaf weed emergence. Sequential S-metolachlor applications resulted in greater weed control. However, no additional benefits were observed in two applications when hand-weeding was utilized. When hand-weeding was performed, there were no differences between one and two applications of S-metolachlor in end-of-season weed biomass (24 and 17 g m², respectively) or onion yield (7.52 and 7.57 kg m², respectively). Tarping reduced early-season weed emergence, but the effects were transient. (2) In 2023 and 2024 studies were conducted at Meigs Horticultural Research Farm, Lafayette, IN to evaluate early-season weed control in potato production. The experiment was designed as a split-plot. The main plot factor consisted of tarping or S-metolachlor (1,947 g ai acre) immediately after planting. Subplots consisted of layby treatments of metribuzin (670 g ai acre), rimsulfuron (26 g ai acre), or nothing. Although tarps caused early injury to potatoes, they recovered. Weed density was similar for both tarping and S-metolachlor at 2 and 3 weeks after planting (WAP). For broadleaves, S-metolachlor resulted in densities of 0.3 and 0.6 plants/m^-², and tarping resulted in densities of 0.3 and 0.9 plants/m^-². Weed pressure was reduced following a hilling 5 WAP. No significant differences were found between layby treatments for weed control or density. The weedy control had 410 g/m² of weed biomass and a yield of 9,790 kg ha^-1, while S-metolachlor had 104 g/m² of weed biomass and a yield of 16,936 kg ha^-1. Tarping had a weed biomass of 168 g/m² and a yield of 16,915 kg ha^-1. In layby treatments, no layby application had 168 g/m² of weed biomass and 16,351 kg ha^-1 of yield, metribuzin had 99 g/m² of weed biomass and 17,779 kg ha^-1 of yield, while rimsulfuron resulted in 136 g/m² of weed biomass and a yield of 16,550 kg ha^-1. (3) An experiment at Meigs Horticultural Research Farm in 2024 was evaluated to explore the utilization of mowing and roller-crimping followed by (fb) silage tarps for cowpea termination. Treatments consisted of mowing or roller-crimping alone, mowing fb tarping, roller crimping fb tarping, cultivation fb tarping, and glyphosate (1529 g ai hectare^-1). Visual evaluations of cover crop senescence (%) showed inconsistent termination by roller-crimping and mowing alone. All tarping treatments achieved 100% senescence at three weeks after treatment (WAT). At 3 WAT, mowing and roller crimping alone had the highest weed densities, 3.05 and 1.78 weeds/m², respectively, while tarp treatments had none. Chlorophyll measurements showed a similar trend across treatments, where treatments with tarping had the lowest chlorophyll content index (CCI) measurements compared to roller-crimping and mowing alone. Cowpeas can be terminated by roller-crimping and mowing when combined with tarping. Silage tarps still hold promise for stale seedbed preparation and early-season weed control. However, their effect on weed control does not last over time, and they require other weed management practices. Additionally, silage tarps could provide farmers with a new method to effectively kill cover crops.