Potential for a Rye Cover Crop to Reduce Nitrate Loss in Southwestern Minnesota

Abstract

Cover cropping practices are being researched to reduce artificial subsurface drainage NO3–N losses from agricultural lands in the Upper Mississippi watershed. This study was designed to investigate the influences of fall planting date and climate on cereal rye (Secale cereale L.) biomass and N uptake in the spring, and to assess subsurface drainage NO3–N loss reductions. A soil–plant–atmosphere simulation model, RyeGro, was developed and used to predict rye cover crop establishment and growth, soil water balance, N cycling, and drainage NO3–N losses from mid‐September through May in southwestern Minnesota. An imbedded stochastic weather generator provided model climate inputs. Inclusion of a rye cover crop sown on 15 September reduced N losses by 11.1 kg N ha−1 or 45% for a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] crop rotation. Fall sowing dates of 1, 15, and 30 October resulted in reductions of 7.8, 5.8, and 4.6 kg N ha−1, respectively, by the end of May. Desiccation of the rye on 1 May resulted in reductions of 4.5, 2.2, 1.2, and 0.7 kg N ha−1, for the 15 September and 1, 15, and 30 October sowing dates, respectively. Cover cropping practice provides promising opportunities for reductions in N losses for cropping rotations wherein the primary crops are harvested before mid‐September and planted after mid‐May. We predict that a winter rye crop can reduce drainage NO3–N losses on average 7.4 kg N ha−1 for southwestern Minnesota if planted on 15 September and desiccated on 15 May.

Corn Nitrogen Fertilization Requirement and Corn-Soybean Productivity with a Rye Cover Crop

“…In addition, RCC has flexibility in establishment, relatively low seed cost, and winter hardiness (Feyereisen et al, 2006). However, research has found differing annual crop yield responses with RCC.…”

Cover crops in the upper midwestern United States: Potential adoption and reduction of nitrate leaching in the Mississippi River Basin

“…However, in Minnesota and northern Iowa, hard frosts and freezing of the surface soil in late October and early November would limit establishment, fall growth, and winter survival of even winter rye (Midwest Cover Crops Council 2012). As a result, drilling or planting cover crops after late corn and soybean grain harvest in these areas sometimes does not result in good establishment and winter survival or much cover crop growth and N uptake (Feyereisen et al 2006).Overseeding or aerial seeding into a standing crop of corn or soybean just before or at maturity allows cover crops to be seeded much earlier than drilling after grain harvest, but it is usually less effective than planting with a drill on the same date (Fisher et al 2011). Overseeding is typically done by a custom application from aircraft, but can also be done by broadcast seeding with groundbased, high clearance equipment.…”

“…However, in Minnesota and northern Iowa, hard frosts and freezing of the surface soil in late October and early November would limit establishment, fall growth, and winter survival of even winter rye (Midwest Cover Crops Council 2012). As a result, drilling or planting cover crops after late corn and soybean grain harvest in these areas sometimes does not result in good establishment and winter survival or much cover crop growth and N uptake (Feyereisen et al 2006).…”

A decade of conservation effects assessment research by the USDA Agricultural Research Service: Progress overview and future outlook

“…In the Northeast, where short growing seasons limit the window for effective fall seeding, simultaneous seeding of a red clover (Trifolium pretense L.) cover crop with corn planting can provide water quality benefits after corn harvest without affecting corn yield (Kleinman et al 2005). In the Midwest, the window of time available to plant winter cover crops and provide for establishment and growth before onset of winter weather diminishes to the north, and recommendations for cover crop fall-seeding dates have been developed into southern Minnesota (Feyereisen et al 2006). In spring, cover crops are killed with herbicides, and timing is important for establishment and N management of the succeeding grain crop.…”

“…In spring, cover crops are killed with herbicides, and timing is important for establishment and N management of the succeeding grain crop. Research results have helped to inform management options in the Midwest (Feyereisen et al 2006;Kaspar et al 2007; and Chesapeake Bay (Clark et al 2007;McCarty et al 2008;Rotz et al 2006).…”