Winter Rye Cover Crop with Liquid Manure Injection Reduces Spring Soil Nitrate but Not Maize Yield

Abstract

In maize-based cropping systems, leaching of nitrate-nitrogen (NO3-N) to drainage tile and groundwater is a significant problem. The purpose of this study was to assess whether a winter rye cover crop planted after silage maize or soybean harvest and injected with liquid manure could decrease soil NO3-N without reducing the yield of the following maize crop. An experiment was conducted at 19 sites with predominant occurrence of Mollisols (15 out of 19 sites) in the upper Midwest USA immediately after soybean or maize silage harvest to compare a drilled rye cover crop and a non-cover crop control. Later in the fall, liquid swine or dairy manure was injected into the cover crop and control plots. Rye was terminated the following spring using herbicide, usually before reaching 20 to 25 cm in height, and incorporated with tillage at most sites, after which maize was planted and harvested as silage or grain. Across sites, soil NO3-N at rye termination was reduced by 36% (range = 4% to 67%) with rye compared to no rye. Nitrogen in aboveground rye biomass at termination ranged from 5 to 114 kg N ha−1 (mean = 51 kg N ha−1). Across sites, there was no significant difference in yield of maize silage or grain between treatments. These results demonstrate in a Mollisol-dominated region the potential of a winter rye cover crop planted before manure application to effectively reduce soil NO3-N without impacting yield of the following maize crop, thereby reducing risk of negative environmental impacts.

Ecological Intensification of Food Production by Integrating Forages

“…There has been increasing interest in the use of winter cover crops following maize (either for silage or for grain) and soybean in regions where water quality is a major concern. Winter cover crops can scavenge excess nutrients from agricultural fields, thus reducing nitrate leaching [57][58][59]. This is particularly important in systems where manure applications are common [59].…”

Additive Type Affects Fermentation, Aerobic Stability and Mycotoxin Formation during Air Exposure of Early-Cut Rye (Secale cereale L.) Silage

“…Along with triticale, rye cut early before maturity has very recently attracted attention in other European countries, e.g., Hungary [1]. Although it is also grown as cover crop between cash crops [2], it is mainly used as forage for silage production in double-cropping systems with maize [3], but cultivation as a summer catch crop has been increasing [4]. The early harvest, which at the latest takes place just before flowering, enables farmers to grow two crops per year, which is usually maize after winter rye and summer rye after cereals or rape seed, thereby increasing land productivity [3,5].…”

Sustainable Cropping Systems

“…The article by Everett et al [43] summarizes a study across 19 sites in the upper Midwest USA that evaluated the effects of a winter rye cover crop on soil nitrate-N and maize yield when sown before autumn injection of liquid manure in fields where the previous crop was silage maize or soybean. Across sites, use of a rye cover crop reduced nitrate-N concentration in the 0-60 cm soil layer in the spring by 36% without affecting maize silage or grain yield, demonstrating its utility for reducing the risk of N losses without restricting maize productivity in these cropping systems.…”