Are No-Till and Organic Converging?

By Brenda Frick, Ph.D., P.Ag.

New technology being tested in the United States combines the advantages of no-till with the benefits of organic production. Organic producers rely on green manure crops to provide nitrogen, build soil organic matter and to reduce weed pressure. Traditionally, the green manure crop was killed and incorporated into the soil by tillage. The no-till crimper-roller developed by The Rodale Institute from Pennsylvania allows farmers to terminate their green manure without the use of either tillage or chemicals, and to seed the next crop in the same pass.

The no-till crimper-roller is a modified roller with a 16 inch diameter drum and 4 inch blades. The blades aren’t meant to cut the crop; they push it over and crimp the stems, forcing them into contact with the soil. In preliminary trials, researchers found that timing was a key to success. If the crop was vegetative, it bounced right back, but when the crop was crimp-rolled at flowering (at least 20% bloom, preferably 50 to 75% bloom), up to 90% of the crop was killed. Terminating at the full flowering stage also allows the greatest nitrogen benefit from a legume green manure. The researchers found that the killed green manure or cover crop formed a mulch layer that suppressed or at least delayed weeds and reduced evaporation from the soil surface.

The design of the implement has been refined over the last few years. The blades are welded on to the drum in a chevron pattern to avoid bouncing and facilitate steering. They are angled back from the direction of motion to reduce the amount of soil they kick up. The drum can be filled with water to increase its weight. Additional weight is particularly useful in dry soil. The crimper-roller is front mounted to avoid the difficulties in obtaining good crop-soil contact in the compacted tire tracks, and to allow seeding equipment to follow the roller in a single pass.

The crimper-roller is being tested at a number of US locations using different crops and under different environmental conditions. The technology will need further fine-tuning and region specific testing. Of particular concern to prairie farmers will be the balance between biological activity that moves the green manure nitrogen into the soil and loss of nitrogen to the air in a dry year. Weeds will also be a concern. Plough-down tillage traditionally reduces weed pressure. In areas with lower growth potential, the mulch produced by the green manure may be less effective at suppressing weeds.

For no-till farmers, the crimper-roller offers the possibility of soil building and reducing nitrogen costs without increasing herbicide use. For organic farmers, the crimper-roller offers the possibility of reducing the time, energy and moisture loss associated with tillage of green manures. This technology appears to be a promising development in the search for a no-till organic system.

Organic producers are exploring other ways of reducing tillage in their production systems as well. Increasingly, producers are moving to a direct seeding system. Some are avoiding fall tillage, using crop residues and fall weeds for winter grazing. This provides valuable feed while at the same time managing weeds, retaining stubble for snow trapping and reducing erosion potential. Other producers are taking land out of an annual tillage cycle by seeding it to perennial soil building and forage crops, expanding their hay and grazing lands at the expense of their cultivated acres. There is interest in perennial food crops, particularly the possibility of perennial cereal crops. If mixed with perennial legumes, these might offer a sustained yield with a minimum of seeding and tillage.

Traditionally, no-till and organic have been considered opposing strategies. As both systems mature, we have the opportunity to learn from each other and move together to more sustainable production.

Brenda Frick, Ph.D., P.Ag., is the Prairie Coordinator for OACC (the Organic Agriculture Centre of Canada) at the College of Agriculture, University of Saskatchewan. She welcomes your comments at 306-966-4975 or via email at brenda.frick@usask.ca.

More information on the no-till roller is available at http://www.newfarm.org/depts/notill/index.shtml

This article first appeared in The Western Producer, and is published here on the OACC website with permission.

Posted on the OACC website, July 2006