For years our organization has been encouraging a systems approach to make direct seeding an even more profitable experience. Crop rotations are the basis of this approach. The art of establishing a good rotation is fundamental to the science of direct seeding in that it influences every other aspect of the system.
Many factors must be considered when designing a rotation: historic rainfall patterns, crop water use patterns, disease and insect cycles, weed control problems, herbicide rotation, equipment needs, seeding and harvest dates, access to markets and overall profit potential and risk management. For instance, a good crop rotation will effectively catch and use water and convert it into the greatest profit potential coupled with an acceptable risk level. Dwayne Beck, from the Dakota Lakes Research Farm in South Dakota, indicates that observing the native vegetation in your farming area can aid in the development of a good crop sequence with proper rotation intensity. Native plants reflect the precipitation, the temperature and the soil quality of a given area.
Beck describes rotation intensity as the demand for water within a given rotation. Inclusion of high water use crops such as alfalfa will increase the intensity. Thus in drier areas, for example the brown soil zone, including both high and low water use crops is desirable. In wetter areas such as the black and gray soil zones, more high water use crops should be included. If fields are consistently too dry, the rotation intensity is too high. Conversely, if fields are invariably too wet, intensity should be increased.
However, addressing rotation intensity without considering crop diversity will inevitably lead to management problems. Including different crop types means not only increasing the rotation diversity but also allowing for herbicide rotations, reducing plant diseases, managing workloads and spreading risk! Even using different plant species within a given crop type (ie. wheat, oats, barley) can add useful diversity to a rotation. Fall seeded cereals (and possibly fall seeded broadleafs such as canola) are also great ways to increase the rotation diversity. Alfalfa simultaneously increases both the diversity and the intensity of a rotation, and has many other favorable attributes Martin Entz has long been emanating.
Crop diversity coupled with proper rotation intensity should improve profitability. Of course crop selection is based on the market outlook. But forces beyond the control of the producer may require refining the traditional considerations when planning a crop rotation. A well thought out rotation allows for risk management now and in the future.
Dwayne Beck is the closing speaker at the SSCA's 10th annual conference in February, 1998. I'm sure he will expand on these ideas during his presentation on direct seeding.