By Jamie Martin
Cover crops are increasingly used by farmers to protect soil and improve water quality during periods when fields are normally left bare. University of Minnesota researchers recently shared findings showing how cover crop management influences success in northern cropping systems.
Research focused on nitrate loss through tile drainage systems found that cover crops can significantly reduce nitrogen movement when they establish properly and produce enough biomass. Studies compared winter cereal rye and annual cover crop mixes in different corn production systems. Results showed that winter cereal rye consistently reduced nitrate concentrations in most years, while annual mixes that winter-killed provided fewer benefits due to shorter growth periods.
A key factor influencing results was weather. Dry conditions limit germination and growth in some seasons, reducing the ability of cover crops to absorb excess nitrogen. Researchers noted that silage corn systems offer more opportunity for cover crop success because earlier harvest allows longer fall growth compared to traditional corn-soybean rotations.
Additional trials examined how seeding rates and termination timing affect cereal rye performance before soybean planting. Surprisingly, biomass levels were similar across a wide range of seeding rates, indicating growers may lower seeding rates without reducing effectiveness.
Later termination produced more biomass because the crop had more time to grow. Soybean yields generally remained stable regardless of seeding rate or termination timing, including planting green in most locations.
Researchers emphasized that cover crops should be placed in systems where they are most likely to thrive, such as short season crops or silage corn rotations. Winter cereal rye continues to stand out as a reliable choice because it tolerates cold temperatures and resumes growth early in spring.
Overall, the studies show that cover crops can improve water quality and soil health without harming soybean yields, but success depends on careful planning, proper species selection, and management suited to local conditions.
Photot Credit: gettyimages-eugenesergeev
Categories: National