Cover crops are flourishing, with seed mixes becoming more specialized depending on farmers’ specific needs.
Two specialists in Nebraska and Kansas who are deeply entrenched in cover cropping provided their professional guidance: Keith Berns; co-owner of Green Cover Seed in Bladen, Nebraska, and Pat Baxa, sales and production at Polansky Seed, Inc. in Belleville, Kansas.
Q: What seed mixes are best for:
Berns: The key to preventing erosion is keep soil covered to prevent the scouring effect of wind on the exposed surface of the soil. Seed mixes that include deep-rooted and high biomass crops like cereal rye, oats, sorghum sudan and millet tend to be the most effective.
Baxa: To reduce soil erosion in a cropping rotation, you’d plant a species that would get quickly established and develop a massive root system — typically grassy type annuals.
Berns: The real reason roots don’t grow into compacted soil is, there’s a lack of oxygen. Compacted soils have reduced pore space, and collapsed passages between pores, so it’s hard for oxygen to diffuse down into the soil. Any tillage makes compaction worse, including subsoiling, but cover crops encourage rhizosphere organisms that live in the immediate vicinity of the roots, to thrive when there are no crop roots. (An interesting read is about the importance of: mycorrhizal fungi.)
Baxa: To reduce soil compaction in a cropping rotation, tap rooting or large rooting species tend to be the seeds of choice. These seeds would be radish, turnip, clovers, sunflower, vetch, okra, rape, safflower, sunn hemp, chicory, and forage collards.
Berns: The best cover crop mixes for grazing are ones that are diverse to provide a nutritious buffet for the livestock. Combining legumes, grasses, brassicas and broadleaf plants will not only provide the best livestock grazing, but also the most soil health benefits.
Baxa: To produce feed for livestock, and high forage production, typical fall grazing cover crop mixes that are relatively simple and economical are oat, radish, turnip, collard mix. These mixes could include grass species like oats, barley, wheat, cereal rye, annual ryegrass, triticale, sorghum sudan grass, or forage sorghums. Brassicas are known for quick growth and nutritious tubers that can provide post-frost nutrients, such as purple top turnips.
Q: What goes into creating these mixes?
Berns: Identifying important resource concerns (erosion, compaction, or infiltration) and goals (nitrogen fixation, pollinators or supplemental grazing, etc.) for the cover crop mix, is the first step in building a proper mix. We take this information, plus the planting date for the cover crop and the following cash crop to determine which of the 100-plus species to use in the best combination.
Baxa: A successful mix will include numerous roots systems and varied growth habits that co-mingle with each other.
Q: Where do popular species like sorghum sudan grass and triticale come from?
Berns: Hybrid sorghum sudan, forage sorghum and pearl millet are grown mostly in northwest Texas where it’s hot enough for full season grown, dry enough for good plant health and irrigation water is available for good production. Open pollinated sorghums, millets and triticale can be grown in a wider geography, including Kansas and Nebraska. Most of our triticale production comes from Oklahoma, Kansas and Nebraska.
Q: How did sorghum sudan and triticale become cover crops?
Berns: Any plant can be a cover crop as long as it’s not part of a producer’s regular crop rotation (so it does not vector or harbor diseases or pests). Sorghum sudan, triticale and cereal rye are very popular because they are very deep-rooted, grow very fast and have high biomass production to feed both the above ground livestock and the below ground livestock (soil biology) which is one of the main reasons to plant a cover crop!
Q: What are the most popular cover crops?
Berns: Cereal rye, because it is the most cold tolerant species we have. Thus, it can be planted late after corn and bean harvest, and still have very good spring growth. This aggressive, early growth will suppress weeds, prevent erosion, build soil structure, and jumpstart the biological activity of the soil prior to the next crop being planted.
Q: More farmers interested in using cover crops:
Baxa: The past several years have seen farmers wanting to become better stewards of the land. Cover crops can provide positive short- and long-term effects for soil health, run off infiltration, added livestock and wildlife food sources and promoting beneficial insects, to name a few. There are also cover crop programs available to help offset the cost, depending on location and availability.
Amy Hadachek can be reached at email@example.com.