Monday, September 12, 2011

Winter rye: a versatile cover crop

Ajay Nair
Department of Horticulture, Iowa State University

Winter rye (Secale cereale L.) is one of the most popular and versatile cover crop in many regions of United States. Because of its cold hardiness winter rye is the only cover crop that can be planted as late as in November or even December in the Midwest and the Northeast. Rye has a wide seeding range from 60-120lb/A and is relatively less expensive ($12-15 for a 50 lb bag). Winter rye can also be grown in mixtures with a legume such as hairy vetch. When growing a winter rye and legume mixture, the rate of winter rye seeding should be reduced to half of its original seeding rate.

Rye cover crop in spring
Cover crop being mowed

Once established in the late fall, rye roots hold the soil protecting it from erosion and compaction due to rains in the fall and spring. The above ground biomass helps captures residual nitrogen that would have otherwise leached away. Rapid growth of rye plant shades the ground and suppresses growth of winter weeds.   Winter rye and its residues release plant growth-inhibiting substances called alleclochemicals that are active against suppressing weeds such as pigweeds, lambsquarters, purslane, and crabgrass. A fast-growing rye cover crop competes strongly for light, nutrients, moisture, and space, and can thereby suppress weed growth and development. As the temperatures increase in the spring, rye produces large biomass which is generally mowed and incorporated into the soil. This stimulates soil microorganisms and adds soil organic matter. Also, because of its potential to produce large biomass, rye has been successfully used in no-till cropping systems, especially for vegetables such as pumpkins and squashes.  
All of these characteristics make winter rye an excellent cover crop for our region and depending upon their rotation plans growers should consider incorporating rye into their production systems. To summarize, benefits of rye cover crop include:
1) Reduction in soil erosion
2) Weed suppression
3) Improvements in soil physical, chemical, and biological properties
4) Recycling of nitrogen and other nutrients
5) Enhancement of cropping system diversity
6) Habitat for beneficial insects
7) Use in no-till production systems

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