@article{mirsky_ryan_teasdale_curran_reberg-horton_spargo_wells_keene_moyer_2013, title={Overcoming Weed Management Challenges in Cover Crop-Based Organic Rotational No-Till Soybean Production in the Eastern United States}, volume={27}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-12-00078.1}, abstractNote={Cover crop–based organic rotational no-till soybean production has attracted attention from farmers, researchers, and other agricultural professionals because of the ability of this new system to enhance soil conservation, reduce labor requirements, and decrease diesel fuel use compared to traditional organic production. This system is based on the use of cereal rye cover crops that are mechanically terminated with a roller-crimper to create in situ mulch that suppresses weeds and promotes soybean growth. In this paper, we report experiments that were conducted over the past decade in the eastern region of the United States on cover crop–based organic rotational no-till soybean production, and we outline current management strategies and future research needs. Our research has focused on maximizing cereal rye spring ground cover and biomass because of the crucial role this cover crop plays in weed suppression. Soil fertility and cereal rye sowing and termination timing affect biomass production, and these factors can be manipulated to achieve levels greater than 8,000 kg ha−1, a threshold identified for consistent suppression of annual weeds. Manipulating cereal rye seeding rate and seeding method also influences ground cover and weed suppression. In general, weed suppression is species-specific, with early emerging summer annual weeds (e.g., common ragweed), high weed seed bank densities (e.g. > 10,000 seeds m−2), and perennial weeds (e.g., yellow nutsedge) posing the greatest challenges. Due to the challenges with maximizing cereal rye weed suppression potential, we have also found high-residue cultivation to significantly improve weed control. In addition to cover crop and weed management, we have made progress with planting equipment and planting density for establishing soybean into a thick cover crop residue. Our current and future research will focus on integrated multitactic weed management, cultivar selection, insect pest suppression, and nitrogen management as part of a systems approach to advancing this new production system.}, number={1}, journal={WEED TECHNOLOGY}, publisher={Cambridge University Press (CUP)}, author={Mirsky, Steven B. and Ryan, Matthew R. and Teasdale, John R. and Curran, William S. and Reberg-Horton, Chris S. and Spargo, John T. and Wells, M. Scott and Keene, Clair L. and Moyer, Jeff W.}, year={2013}, pages={193–203} }
 @article{wells_reberg-horton_smith_grossman_2013, title={The Reduction of Plant-Available Nitrogen by Cover Crop Mulches and Subsequent Effects on Soybean Performance and Weed Interference}, volume={105}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2012.0396}, abstractNote={A 3 site‐year study was conducted to investigate the impact of roller‐crimped rye (RC) (Secale cereale L.) mulches on soil N immobilization and subsequent effects on weed suppression and soybean [Glycine max (L.) Merr.] yield. Treatments consisted of: (i) RC, (ii) conventional tillage with neither rye cover crop nor weed control measures (WC), (iii) conventional tillage plus herbicide weed control (CT+HB), and, (iv) roller‐crimped rye plus herbicide (RC+HB). The rye biomass varied between the sites with 4400, 8300, and 7084 kg ha−1 dry matter (DM) for Goldsboro 2009, Kinston 2009, and Kinston 2010, respectively. During the season, the flow of soil inorganic N was monitored via ion‐exchange probes and by direct extractions at two depths (0–10 and 10–25 cm) every 2 wk. Tissue data was collected every 2 wk on soybean and redroot pigweed (Amaranthus retroflexus L.) to determine the C/N ratio. For all sites, peak N immobilization occurred between 4 and 6 weeks after planting (WAP), indicated by a reduction in soil inorganic N. Results from the ion‐exchange probes showed similar trends of the extractable soil inorganic N at all sites. Pigweed C/N ratios revealed a growing divergence between the two systems, with a severe N deficiency in the RC. Even with varying rye biomass production across environments the RC system created an extremely low N environment, suggesting that when a cereal cover crop is paired with a legume cash crop, reduced weed crop interference may result, with little reduction in soybean yield.}, number={2}, journal={AGRONOMY JOURNAL}, publisher={American Society of Agronomy}, author={Wells, M. S. and Reberg-Horton, S. C. and Smith, A. N. and Grossman, J. M.}, year={2013}, pages={539–545} }