So, you added wheat into your rotation to help diversify the market opportunity of your operation. Now that the wheat is off and straw is baled, that field is a clean slate. This also offers you a tremendous chance to build your soil and scavenge some nutrients.
With half a growing season left, why not plant a diverse cover crop to help build soil health in that field? By planting a multi-species blend of cover crops, you increase biodiversity in your field, with each species playing a unique role to help you achieve your goals. What are your goals?
There are six common goals that most farmers try to achieve with their cover crop program. Creating a goal for your soil allows you to select the cover crop species you plant for the specific purpose you have in mind.
Usually, with cover crops, you are trying to reduce erosion, increase soil organic matter, scavenge excess nutrients, suppress weeds, minimize compaction and fix nitrogen. Depending on your crop rotation, your goals may change from year to year.
In a typical corn, bean and wheat rotation, the harvest of wheat offers you a window to grow some warm-season covers and meet a few of those goals.
Mixes containing sudangrass or sorghum sudan hybrid are excellent at erosion reduction, increasing soil health, scavenging nutrients from deep down in the soil profile and suppressing weeds and pests.
Adding a legume into the mix allows for atmospheric nitrogen fixation as well. Usually, there is some nitrogen left in your soil profile following a cash crop. By adding in a cover crop you can typically trap that nutrient and make it more available for the next cash crop otherwise it would leach away and be lost.
Once you decide on your goals for the planting, you can look at all the other factors such as termination, seeding dates and seeding method. You’ve decided that you are going to plant a cover crop after your wheat that will give you the most overall benefit going into your next cash crop. Well, when are you going to be planting it?
Most species have an optimal range of seeding dates to get the desired benefit of the planting. Maybe wheat came off later than you thought, or weather impacted your straw baling. That would play a part in species selection.
How are you planning to terminate your cover? Are you using a herbicide spray program to terminate, or will you be roll crimping, or planting only winter kill species?
If you are not planning on using spray or do not have access to a roller-crimper, then picking a winter kill species is necessary. Winter kill species include oats, turnips, radishes and any warm-season species.
Factors like the carbon-nitrogen ratio must also be considered. Maintaining a carbon-nitrogen ratio of 24:1 is optimal for microbial soil life and will tie up minimal nutrients. If you don’t consider ratios and plant high carbon plants, such as pure stands of grass, you will tie up nitrogen in the decomposition process and make that nutrient unavailable to your next cash crop.
Considering these factors in your planning procedure will give you a step up on successfully building soil health and setting that field up for success in the future. For more detailed information on planting cover crops in your field contact your local soil and water district or USDA NRCS, conservation planner.