Basics of No-Till - Residue Management and Plant Establishment

Terry Gregoire. Area Extension Specialist in Crop Production, Devil’s Lake, ND

Adoption of no-till systems is becoming more common as technology brings new developments into common practice. Price reductions in glyphosate, continued development of herbicide tolerant crops, genetic improvements in crops, new innovations is seed openers and equipment, and recent government regulations, programs and financial incentives to encourage adoption of conservation tillage are some of the reasons for switching to no-till production seeding.

Research and grower experiences over the past 25 years of no-till production efforts have established some of the critical factors in establishing a successful no-till system. One of the first determinations a grower should grapple with is deciding a proper crop rotation that establishes appropriate crop diversity and intensity for their region. Duane Beck and others have a web site at www.dakotalakes.com that contains many excellent articles on this subject.

Another decision to be made is determining the seeding equipment to be used. Among the many decisions in purchasing seeding equipment is deciding on the type of opener and shank spacing consistent with the amount of soil disturbance the grower wants to achieve. These choices will ultimately influence residue management techniques used to maximize the benefits of residue and minimize residue impact on seedbed conditions and plant establishment. Residue decomposes slowly in northern regions of the great plains. It may take up to 3 years for previous crop residue to disappear from the soil surface depending on the crop and environmental conditions. If not managed correctly, residue accumulations can negatively impact crop establishment.

"Residue management is important to the success of no-till farming. Residue management affects erosion control, moisture conservation, seed and fertilizer placement, crop emergence and weed control. Residue management starts at harvest time when you handle straw and chaff from the combine.

Spread the straw and chaff as evenly as possible. The best way to do this is with good straw and chaff spreaders on the combine. It may be necessary to harrow after harvest in a year with particularly heavy straw. However, a well adjusted straw chopper/spreader can make harrowing unnecessary most years. It is NOT POSSIBLE to spread chaff effectively by harrowing. An efficient chaff spreader will prevent that two or three inch thick blanket behind the combine. If the chaff is not well spread, there will be problems all season long. The first problem is poor performance of the seeder through the chaff row. Plant growth will be weak with spindly plants which are more susceptible to disease. There will be extra growth of weeds and crop volunteers in the chaff row as well as more weed problems because of reduced competition from the crop. Finally, there will be later maturity in the strips which will delay harvest. Another problem is a biochemical interaction called allelopathy where the residue from certain plant species may exude growth inhibitor. Because of this, in poorly spread chaff rows, there is often noticeably less crop growth in a subsequent year.

While harrowing is not an efficient means of spreading the chaff and straw, there is another reason why some zero tillers harrow after harvest. Harrowing can promote fall growth of weeds and crop volunteers and can be a way to make the fall weed control program more effective." (Zero-till production Manual)

Garth Patterson and Garry Meier in the January 1995 issue of Grainews offered additional tips on residue management.

  1. Rotate among crops that have high and low residue production.
  2. Grower shorter-strawed varieties
  3. Residue from crops such as barley and legumes break down faster than wheat and corn
  4. Use lifting devices or pickup reels in a lodged crop
  5. Crop desiccant use increases residue break up when passing through harvesting equipment.
  6. Leave stubble height consistent with seeding equipment capability to handle residue.

Some times various designs of residue movers and use of cutting coulters can be successfully used in appropriate situations. Livestock operators can also choose to bale straw or use straw and chaff collectors to remove excess residue.

A well designed rotation that has a diverse mix of grass and broadleaf crops that includes legumes will have minimal problems with residue accumulation and management as these crops will produce both low and high residue levels and have varied break down rates.

Good residue management is the first step to minimize or eliminate problems in a successful no-till production system.