Broadcast cover crop seeds often don't have good seed-to-soil contact, and stand counts of broadcast cover crops are often lower than those of drilled cover crops, says the University of Nebraska. A recent study shows that increasing the seeding rate can improve cover crop productivity, but only in some cases.

A study found that legume covers actually supplied little total nitrogen due to low biomass production, while the nitrogen contained in cereal rye residue was likely readily available for the next corn crop.

A study concludes that most negative effects of cover crops on corn growth are short-lived, says University of Nebraska Extension.

The Iowa State University Horticulture Research Station assessed five cereal rye cultivars for their anthesis timing, biomass production and carbon-to-nitrogen ratios.