Water is a critical part of the dryland farming system - the amount and timing is up to Mother Nature, but the management is up to farmers. To fit current conditions in the region, farmers are experimenting with tools to use excess moisture in the spring, while at the same time conserving moisture for crop use later in the growing season.
One versatile tool that can be added to the system is a cover crop. Conservation tillage and drainage are also options and should be used in combination with other approaches.
I primarily want to talk about cover crops as a moisture management tool. One species that is gaining popularity in this region is cereal rye. Farmers are trying rates from 20 to 70 pounds per acre with planting dates ranging from interseeding cereal rye in corn in mid-June to seeding post-harvest in late October.
Cereal rye removes water from the soil through transpiration when it starts growing in the fall and then again in the spring after over-wintering. Most of the moisture removal will come in spring when rye is growing quickly.
Cereal rye also helps with water movement down into the soil along root channels. This, along with the cereal rye residue after termination, helps store and retain soil water for crop use later in the growing season.
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Here are a few tips for using cereal rye:
• Rotation: With any cover crop, think about your current and next crop in rotation. Do not use cereal rye before a wheat crop because of volunteer issues. Also, do not plant corn into a living cereal rye cover crop because of allelopathic effects, soil drying, nitrogen tie-up and disease carry-over.
• Termination timing and guidelines: Risk Management Agency guidelines need to be considered if you decide to plant a cash crop directly into a living cereal rye cover crop. Look further into these guidelines before deciding to plant green. Also, if it is a dry spring, cereal rye could be terminated early to avoid drying out the seedbed too much.
• Seeding rates/timing: Consider soil texture when selecting seeding rates. On a sandy soil, rates should be lower (20 to 30 pounds per acre) and in a high clay soil, bump up the rates (30 to 40 pounds per acre or higher) when seeding. Most farmers recommend that you increase the seeding rate as you get later into the fall or if you broadcast.
Reducing tillage is another tool. Residue in reduced till systems can be a challenge in the spring (which is why cereal rye is a nice addition), but water stored in the soil profile can come in handy later in the season. To maximize investments in drainage, use cover crops and reduced tillage to get the water to the tile lines, and prevent the soil from moving off the field with ditching.
Find a balance with these approaches to achieve successful water management on your farm. For more information, visit the NDSU Soil Health webpage: NDSU.edu/soilhealth or follow me on Twitter: @NDSUsoilhealth.
