Organically Managed No‐Tillage Rye–Soybean Systems: Agronomic, Economic, and Environmental Assessment

Abstract

A major challenge that organic grain crop growers face is weed management. Th e use of a rye (Secale cereale L.) cover crop to facilitate no-tillage (NT) organic soybean [Glycine max (L.) Merr.] production may improve weed suppression and increase profitability. We conducted research in 2008 and 2009 to determine the eff ect of rye management (tilling, crimping, and mowing), soybean planting date (mid-May or early June), and soybean row width (76 or 19 cm), on soybean establishment, soil moisture, weed suppression, soybean yield, and profi tability. Soybean establishment did not diff er between tilled and NT treatments; and soil moisture measurements showed minimal risk of a drier soil profi le in NT rye treatments. Rye mulch treatments eff ectively suppressed weeds, with 75% less weed biomass than in the tilled treatment by mid-July. However, by this time, NT soybean competed with rye regrowth, were defi cient in Cu, and accumulated 22% as much dry matter (DM) and 28% as much N compared to the tilled treatment. Soybean row width and planting date within NT treatments impacted soybean productivity but not profi tability, with few diff erences between mowed and crimped rye. Soybean yield was 24% less in the NT treatments than the tilled treatment, and profi tability per hectare was 27% less. However, with fewer labor inputs, profi tability per hour in NT rye treatments was 25% greater than in tilled soybean; in addition, predicted soil erosion was nearly 90% less. Although soybean yields were less in NT rye mulch systems, they represent economically viable alternatives for organic producers in the Upper Midwest.

Overview of Organic Cover Crop-Based No-Tillage Technique in Europe: Farmers’ Practices and Research Challenges

“…Several papers have been published in North America on organic MBNT, summarizing the results of research trials based on cover crop species [21][22][23][24][25][26], cover crop termination methods and timing [24,[27][28][29][30][31][32][33], weed suppression [34][35][36][37][38][39][40][41], and cash crop sowing (fertilization strategies, row spacing, seeding rate) [24,42,43]. Nevertheless, in Europe, very few studies exist that focus on organic MBNT, raising questions of the effectiveness and appropriateness of this technique to enhance the sustainability of European organic farms [44].…”

“…Cereal rye has been the most researched cover crop in North America prior to soybean MBNT and has led to the most promising results regarding the range of benefits conferred (e.g., allelopathic effect, high biomass, early flowering, flexibility of sowing date, kill by rolling, etc.) [26,39,42,76]. Researchers also extolled the benefits of other cereal cover crops (e.g., triticale, barley, etc.)…”

Impacts of Organic Zero Tillage Systems on Crops, Weeds, and Soil Quality

“…The plants that survive compete for water and nutrients with the market crops seeded after rolling-crimping the cover crop [45]. Competition from a small percentage of cover crop plants may be a minor nuisance in sub-humid and humid environments in fields where soil fertility levels are high, but they pose a significant obstacle to successful production of market crops in regions with limited rainfall and/or low soil fertility levels because of their competition for growth resources [38,40].…”

The Current State and Future Directions of Organic No-Till Farming with Cover Crops in Canada, with Case Study Support

“…The most common method of termination is by way of the roller-crimper, a cylinder with angled blades running along the outside in a pressure-maximizing chevron curve that achieves 90-100% termination in one pass [9] (p. [43][44][45][46][47][48][49][50]. This method was designed collaboratively at Rodale Institute to achieve a number of goals, unavailable through other termination methods like those employing mowers [9] (pp.…”

“…This method was designed collaboratively at Rodale Institute to achieve a number of goals, unavailable through other termination methods like those employing mowers [9] (pp. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. The roller-crimper lays down a cover crop neatly and evenly and crushes the mature stems without severing them [9] (p. 44).…”