Does your rotation include diversity and intensity? Does it maximize your soil's profitability? What is your native vegetation telling you? Recently Dr. Dwayne Beck of the Dakota Lakes Research Farm performed no-till brain transplants on a few of us canucks.
During the first week of July, I had the privilege of participating in a no-till tour of South Dakota, sponsored by Monsanto, Alberta Reduced Tillage Initiative, Flexicoil, and Southern Alberta Conservation Association. The tour included stops at the Indian Head Research Farm, the Dakota Lakes Research Farm, and several progressive no-till farms.
Many of the ideas impressed upon us in South Dakota, were similar to what researchers like Martin Entz, Doug Derksen, Brian McConkey, George Clayton, Guy Lafond and others have been stressing north of the border. Perhaps the most notable difference is that Canadian experts offer these ideas as polite suggestions. South of the border these directives are given as strong guidance.
Nonetheless the same concepts hold true - encourage fast uniform canopy formation through accurate seeding depth into properly managed residue to ensure good seed to fertilizer separation.
At the Dakota Lakes Research Farm Beck is continually changing and improving on a drill which can seed and fertilize in one pass. The challenge for Beck is to develop a seeder that can seed corn (traditionally a 30-inch+ row crop) as well as wheat and other traditionally narrow spaced crops. His present seeding unit is 12.5 feet wide (wings can be added later to increase the width) and is used to seed the 800 acres of cropland on the farm. All crops are seeded on 15-inch row spacing (which is a significantly narrower than even the more radical 22-inch row spacing on some of the newer row-crop seeders). The 15-inch row spacing in corn allows for much quicker canopy closure.
Canopy closure is the first important concept in Dr. Beck's philosophy. Allow the crop to establish fast and provide less than optimum conditions for the weeds, thereby providing as much crop competition as possible. The less disturbance the better (hence the disc drill). The use of disc drills makes it possible to harvest with a stripper header, which itself increases the capacity of the combine. This allows a smaller combine to cover many more acres.
The next important aspect of a finely tuned system is rotations. This may mean using more than one rotation. The process should provide the proper diversity, intensity, and profitability for each individual field based on native vegetation and soil type. Since 1991 three dryland rotations have been practiced at the Dakota Lake Research Farm. They are: (1) winter wheat (cool season grass) - corn (warm season grass) - cool season broadleaf (flax, canola, lentils, field peas), (2) winter wheat - corn - warm season broadleaf (soybean, sunflower, safflower, chickpeas, dry beans) - spring wheat, (3) winter wheat - warm season broadleaf - corn - cool season broadleaf.
By having diverse crop types, seeding and harvesting dates are automatically altered which aides in weed control. Each crop type favors and discourages a different spectrum of weeds. Perennial and forage crops can be excellent tools to control certain weeds. Having a diverse rotation allows diversity in the herbicide program to be used. It also spreads out risk and workload. One can handle more acres with the same fixed costs. Diversity can also create the proper conditions for the subsequent crop. For example, a dark colored residue produces a warmer seedbed in the spring.
The next important component of Dwayne's philosophy is altering the intensity of the rotation. Proper intensity reduces risk. How many times have you heard someone say I have to use tillage to dry out the land in the spring? Dwayne's reply: "Rotations with insufficient intensity will be too wet in the spring." The other side of the coin is that rotations with excessive intensity will be too dry. That means poor plant growth in average years. Proper intensity depends on weather, soil type, and land location.
If weather tends to be variable, utilize two or more rotations. Have the ability to put flex crops into the rotation based on the weather (forage the crop if it's a dry year, grain if it's a wet year). Soils that have high water holding capacity require more intensity and more high-water use crops. Coarse textured soils require slightly less intensity: more short-season crops and less inter-crop time. The important thing to remember is that when a producer begins direct seeding the intensity should be greater than that of conventional tillage. More water is stored and greater water-use efficiencies will be attained under a direct seeding system. Therefore the intensity must be increased to avoid undesirable effects from that extra moisture.
Another concept Beck is working on is stacked rotations, allowing a four-year gap between broadleaf crops. This allows the disease intensity to be greatly reduced before coming back with two of the same crops grown back to back. For instance, spring wheat - winter wheat - corn - corn - field pea - field pea.
Is it a good rotation? Only time will tell but it does pose the question: how does your rotation stack up?
For anyone wishing to look up additional information about the Dakota Lake Research Farm they can be located at www.DakotaLakes.com.