Rye as a winter cover crop in northern New England

Cereal rye is an excellent choice as a winter cover crop, especially in northern New England, because it rapidly provides ground cover to hold the soil in place and can withstand cold winters with sub-zero temps. It has deep roots that help prevent soil from becoming compacted in annually tilled fields and in gardens where folks may end up walking and compressing the soil. Rye’s extensive root system enables it to scavenge nutrients from the soil profile and build small air tunnels into the soil, which allows more water and better nutrient flow.  In a no-till situation, it also can help control weeds.

Rye is one of the easiest crops to grow. Recommended seeding rates vary from 60 to 200 pounds per acre, depending on whom you ask.  

Rye provides ground cover, scavenges nutrients from the soil profile, and helps control weeds.

 

Rye, like wheat, will respond to nitrogen (N) fertilizer. When it follows corn and other crops fertilized with nitrogen, however, it seldom requires additional N. Rye has a good reputation for scavenging residual soil nitrogen when it follows other crops, and it is commonly grown for this purpose. Research indicates that rye can extract 40 to 80 pounds per acre of residual N. This reduces the potential for nitrate leaching into groundwater and conserves nitrogen fertilizer inputs.

Mowing or using a burn-down herbicide is an effective way of killing a rye cover crop so that no-till plantings of corn, soybeans, or another crop can be established. If mowing is the chosen method of killing the rye, do so at the flowering stage. At this stage, the anthers are extended, and pollen falls from the seed heads when shaken. If mowing is done earlier, the rye simply grows back. Rye provides better weed control when killed and left as a no-till mulch than when soil-incorporated.

In the greatgrandmother.org gardens, we don’t till the rye.  Rather, we get on our knees and lightly tug at the grass, turning it over gently into the soil.  We are amazed at the long tiny white roots that have been working all winter and early spring to keep the soil healthy.  We don’t even wait the requisite two weeks before planting; we just wait a day and then drop in our seedlings.

Natural plant chemicals that leach out of the rye mulch work to inhibit the germination of small-seeded weeds for about 30 days. When rye is left as a surface mulch, however, the option of killing escaped weeds by cultivation is largely precluded. A no-till cultivator still can be used, but it will disrupt the mulch cover, ending its contribution to weed suppression. North Carolina weed scientist Dr. Douglas Worsham concluded that not tilling plus using a mulch achieves the highest degree of weed control without using a pre-emergence herbicide.

When the rye cover crop is incorporated into the soil, the field can be easily cultivated but the weed suppression provided by the rye will be largely gone. Of course, the rye holds the weeds back while it is growing, but cool-season weeds are usually not a problem in summer crops.