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This is not your dad’s cover cropping

Farmers are using cover crops in farming systems that work for their goals.

May 11, 2023

9 Min Read
cattle grazing cover crops
GRAZING CATTLE OR OTHER LIVESTOCK: Including livestock grazing in a cover cropping system makes sense for some farmers. Whether they run beef cattle themselves on the cover crops, lease the cover crops to other grazers or harvest the cover crops for forage for dairy cattle or other livestock, these farmers are making the system work for them.Kevin Schulz

by Jennifer M. Latzke, Sarah McNaughton, Fran O'Leary and Kevin Schulz

Farmer dads know a lot of things. From the optimal time to start planting corn, to the best way to check if wheat is ripe, they pass their wisdom to the next generation.

Some farmers, however, are bucking the fatherly wisdom from previous generations when it comes to implementing cover crops and livestock grazing in their farming systems.

cover crops in cornstalks

The USDA Economic Research Service reported in 2021 that according to data collected in the 2017 Census of Agriculture, farmers reported planting 15.4 million acres of cover crops — a 50% increase compared to the 10.3 million acres reported in 2012. Cover crops are often implemented as one of several conservation practices in a farm’s overall soil health system, along with no-till farming and nutrient management planning.

Making covers pay

Dean Sponheim is a fourth-generation farmer from Mitchell County in northern Iowa who started farming with his father and brother in 1979. Today, Sponheim is forging a new path from tillage to cover crops. At first the conversion was for economic reasons, but he quickly saw the environmental benefits as well.

Keeping soil intact is important to Sponheim, and the use of cereal rye as a cover crop has done the job.

Wind erosion is a particular concern, and he has found the benefit of cover crops keeping his soil in place.

He remembers growing up, and his father taking pride in seeing the black-covered snow in ditches along roadways, “because that meant we had our tillage done,” he says. “Isn’t that crazy? That’s awful.”

cover crop of peas and radishes

Sponheim incorporated strip-tilling in 1999, and in 2004 started a custom strip tilling business. He began strip cropping in 2011. In fall of 2012, he started aerial applying cover crops, and in 2014 he started a cover crop business — Sponheim Sales & Services — with son Josh and co-worker Rachel Amundson.

That first cover crop was a five-way mix that cost about $50 an acre just for seed. It was a dry fall in 2012 and nothing grew, he says. Meanwhile, his neighbors raved about their cover crops, only for Sponheim to find out they were using a single species — cereal rye. He’s since adjusted his cover crop species to include winter camelina, which looks promising, he says.

From 2015 to 2021, Sponheim saw a 7-bushel-per-acre bump in corn yield with cover crops, versus corn ground with no cover crops. “Do you think 7 bushels would pay for $30 worth of cover crops?” he asks. On the soybean side, he has only seen a bump of a half-bushel per acre.

Yet, Sponheim sees an even greater benefit to his soils, which stay in his fields. While he may be disappointed in his organic matter growth of about 0.04% a year, he attributes that to the soils he farms.

“But that’s OK — I’ve stopped the curve. I’m not going down,” he adds. Sponheim also points to Iowa State University data to stress the importance of building soil organic matter. Data show that a 1% increase in soil organic matter is worth about $1,200 in added nutrients per acre.

And today, he only applies commercial fertilizers at removal rates. As an example, his practices gain his ground about 4.3 pounds of phosphorus per year, and about 23 pounds of potassium per year.

Sponheim says by planting cereal rye, doing an herbicide termination, he nets $46.81 an acre by using cover crops; and if you add another $14 for a tillage pass, he nets about $60 in a no-till situation.

shares of acreages with cover crops graph

Sponheim’s farmer dad advice? Remember the three Ps: “You’ve got to plan, you’ve got to be patient, but you’ve got to be persistent.”

Livestock forage

Cover crops don’t just armor the soil against weeds and erosion in between cash crops. They can also be ideal forage for a wide range of livestock.

Dairymen, like Matt Lippert and son Paul, have found harvesting cereal cover crops like oats, winter rye or triticale, allows them to capture highly digestible nutrients while boosting forage inventories at the same time. Lippert is the University of Wisconsin-Madison Extension dairy educator for Clark and Wood counties, Wis. This father-son team owns and operates a 1,500-acre dairy farm in Wood County, milking 720 registered Holsteins and Jerseys with a 31,000-pound herd average. and they raise 620 dairy heifers.

“My son is into cover crops,” Lippert says. They use winter rye and triticale covers to extend their forage inventories for their lactating cows as well as their heifers.

Lactating cows, he advises, do best with early-harvested covers, whereas heifers and dry cows can do just fine on later-harvested covers.

“Forage quality is going to go from higher-than-average fiber digestibility to lower-than-average fiber digestibility in just a few days,” Lippert cautions. Harvesting rye in May, for example, can be tricky to time with other activities on the farm.

“Rye goes from being highly digestible to being straw very quickly,” Lippert notes. “And with all the things you have to do the middle of May, the rye is saying ‘Chop me now.’ Triticale is a little more forgiving — but it is a relative, so the same thing can happen to it. Both should be harvested in the boot stage for high-quality feed for cows.”

“The feed quality won’t be as high if the rye or triticale heads out, but the tonnage will be higher and it will still be excellent feed for heifers and dry cows,” he says.

Production timing

The Lipperts harvested their corn silage in September, and then seeded 500 acres with a winter rye cover crop.

“We only plan to harvest about 25% for forage in May,” Lippert says. “It could well be feed for cows, but if we have a muddy spring, it will be for heifers. It gives us options. If we had a big alfalfa winterkill, we would have had all these acres of cover crops to harvest for feed.”

Lippert advises:

  • Seed winter rye and triticale in the fall for a May harvest. Lippert says you can seed separately or as a blend, but it’s ideal to follow September corn silage or soybeans. The later you seed, the less growth you get and the less forage to harvest in May.

  • Oats and triticale are useful. Lippert says they work for an early-season feed in November, either chopped or as baleage. They work well seeded after wheat harvest, or a canning crop, in mid-July to August. Oats will die out over winter, but the triticale will regrow for a second harvest in mid- to late May. “It makes really nice feed,” he says. “It’s high in energy and in sugars.”

Fall cover crop adoption by cash crop, 2007-21

When it comes to cover crops, farmers are finding new ways of implementing them on their farms every day. From improving soil health, to a forage resource for livestock, farmers are showing that today’s cover crops aren’t the ones their fathers once knew.

A little grazing advice

Cover crops can make an ideal forage for grazing cattle or small ruminants like sheep and goats. It’s one example of implementing the fifth principle of soil health — integrating livestock in the system.

But before you start planting a cover crop seed mix or buying a load of cattle, North Dakota State University and Kansas State University experts offer some advice.

The first step is to select the right mix. Common selections for grazing include cereal grains, oats, annual ryegrass, peas, sudangrass, brassicas and clovers. Be mindful of your season of use, the seed availability and cost. NDSU Extension recommends a mix of cool- and warm-season grasses, broadleaf crops and legume species for diversity. The goal is to increase soil health benefits from the various cover species, while also extending the grazing period.

Be mindful of these other points:

  1. Nitrate toxicity. Cattle can be susceptible to nitrate toxicity that can occur in cereal grains, forage corn, brassicas and pearl millet crops. Forage test to ensure safe nitrate levels, especially in drought.

  2. Prussic acid toxicity. Watch for prussic acid toxicity in sorghum and sudangrass, especially after a frost. Testing can be a difficult process, so NDSU Extension advises keeping livestock from grazing those crops on immature growth or regrowth immediately after haying, or for seven to 10 days after frost. K-State also warns against grazing or haying flax for its prussic acid potential.

  3. Avoid these species if grazing. Hairy vetch, while a great nitrogen-fixer, can be toxic to cattle and horses, with a mortality rate from 50 to 100%, usually due to kidney failure, according to K-State Extension experts. Also, there are six lupin species particularly toxic to cattle and sheep: silky lupine, tailcup lupine, velvet lupine, silvery lupine, summer lupine and sulfur lupine. They can kill sheep and cause a variety of birth defects when consumed by pregnant cows.

  4. Supplementation. Brassicas, for example, are high in moisture and low in fiber, so be sure to offer other dry feeds to maintain rumen functionality. Depending on the cover crop mix you plant, you may need to supplement with a balanced mineral to meet cattle’s copper, manganese and zinc requirements.

  5. Grazing management. Remember your soil health goal with the cover crop requires you to leave enough residue to maintain the benefits of the growing crop, K-Stat experts say. Whether choosing continuous grazing or some form of rotational grazing, monitor the field as well as the stock health through your grazing period. Ensure there’s a ready water supply as well.

Look to the Midwest Cover Crops Council’s Cover Crop Decision Tool to help you in your species selection, midwestcovercrops.org/covercroptool.

Find more information at morton.k-state.edu/crops-livestock/uploads/GrazingSummerCoverCrops.

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