Last week, we looked at two of the rotations Dwayne Beck uses on his dry land acres at the Dakota Lakes Research Farm, Pierre, S.D.
The first rotation is a simple rotation of cool season grass, warm season grass, and cool season broadleaf. A lot of continuous no till crop producers use this rotation on their farms. We use this rotation of our farm with a rotation of winter wheat, corn, and field pea, then back to winter wheat and repeated. This rotation utilizes two thirds high residue crops which produce enough carbon to the system to maintain or increase organic matter content of the soil.
The second rotation we looked at is a cool season grass, warm season broadleaf, warm season grass, cool season broadleaf. This rotation has only 50 percent high residue crops and the lack of carbon this rotation produces begins to show in poorer yields over an extended period of time on dry land acres. Beck’s research has shown considerably lower winter wheat yields in this rotation when compared to winter wheat yields in the higher carbon producing rotations.
We are going to adopt this rotation on our irrigated acres. We plan to move to a winter wheat, edible bean, corn, field pea rotation on our irrigated acres. I think the agronomical benefits will result in higher yields being produced by the irrigated crops using this rotation.
This rotation will give us more diversity in the rotation than the winter wheat, corn, edible bean rotation we are currently using. This rotation will also allow us to diversify our herbicide program. I also think this rotation will diversify our soil microbial populations by adding a cool season legume with the field peas.
This rotation will also allow us to plant winter wheat in a timelier manner than our former rotation of planting winter wheat behind edible beans. I would also like to put a forage crop in behind the winter wheat for grazing to eliminate some of the wheat residues to plant our edible bean crop into.
We also feel the corn will get off to a better start if we plant it into the edible bean stubble rather than the winter wheat stubble we are currently planting our corn into. We also feel the field peas will perform better in the high corn residues than the edible beans in our current rotation.
We have begun making the rotation change on our irrigated acres this year and will slowly move into this diversified 4 crop rotation. We can make up for the lack of carbon in this rotation with the use of irrigation. I wouldn’t use this rotation on dry land acres due to the lack of residues and carbon in the rotation.
Beck also designed a rotation in 1990 that would fit the farm program at the time. Most producers had a 50 percent wheat base so Beck designed a rotation of spring wheat, winter wheat, corn, and broadleaf. This allowed producers the opportunity to maintain their wheat base acres. The problem with this rotation was too much wheat in to short a sequence. Cheat grass and some diseases became problematic.
After the Freedom to Farm legislation was passed the rotation was diversified to a wheat, wheat, corn, corn, broadleaf rotation. This rotation had a long enough break between wheat crops the cheat grass and disease issues subsided compared to the original rotation. Spring wheat is generally the first wheat planted, but can be winter wheat as well. Sorghum may be substituted for the first year corn in this rotation as well.
The North unit of the Dakota Lakes Research farm is heavier clay soil. Beck uses a winter wheat, winter wheat, broadleaf, corn, corn, broadleaf rotation on this farm. With this rotation he isn’t trying to plant into heavy winter wheat residues in the early spring. He is using some teff grass in place of corn in the first year of the corn sequence. He may also use sorghum in place of corn. The broadleaf crops may are usually flax or field peas but may include lentils, canola, safflower, chickpeas, carinata, or camelina.
It’s interesting to look at the different rotations Beck has designed to meet the varying resource concerns on his farm. He has more flexibility being a research farm than most of us have on our farms due to marketing and crop insurance availability of various alternative crops. I think it is helpful to look at rotations other producers and researchers have utilized and to take some of their concepts and adapt them to your own operation when designing a crop rotation that best fits your farm or ranch.
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