Cover Cropping Winter Rye After Corn Silage and Effects On Water Quality, Soil Nutrient Status, and Forage Yield.

A typical cropping system for confinement dairy production may include consecutive years of corn silage accompanied by annual manure application.  High manure application may lead to nutrient leaching and soil nutrient build up, and the short corn growing season may not maximize annual biomass production.   We hypothesize that seeding rye after corn silage may mitigate environmental issues associated with corn silage production.  When harvested as forage, the value of the rye as feed may offset some of the cost incurred with cover cropping.  On farm and plot scale research studies have been designed to test these hypotheses.  On farm, corn silage production with and without a rye cover crop is compared on adjacent 60 ha fields.  In one year of data, rye seeded after corn silage reduced nitrate leaching the following spring by 23% compared to fallow, but subsequent corn silage yield was reduced by 16%.  At the plot scale, spring soil nitrate was reduced by as much as 75% in the rye treatments, and nitrate concentration in leachate was reduced by 65% in one year of data.  In general, corn planted after rye demonstrated delayed development and yielded lower compared to corn after fallow.  There was no statistical difference in biomass production between the corn only and corn/rye treatments.  This research demonstrates that rye cover cropping may provide environmental benefit in a corn silage production system, but reduction in corn silage yield after rye is likely.