Cover crops: Crucial to soils

by Tamara Scully

A day-long conference sponsored by the North Jersey Resource Conservation and Development, a non-profit focused on natural resource use in the agricultural sector, attracted a significant number of New Jersey farmers. Aside from NJRC&D presenters, however, the speakers were all from Pennsylvania. Penn State, Rodale Institute and several Pennsylvania farmers and Certified Crop Advisors provided attendees with an array of practical no-till and cover crop information.

No-till practices help to build soil organic matter by eliminating the rapid microbial activity that occurs with tillage, protecting the soil structure. But no-till itself is only one step in eradicating soil and nutrient erosion concerns, optimizing soil organic matter content, increasing nutrient availability for the crops, and enhancing soil structure.

“No-till is important,” said farmer Jim Hershey, president of the Pennsylvania No-till Alliance. “This system of no-tilling is not complete without cover crops.”

Hershey operates a 500-acre Pennsylvania farm, growing wheat, corn and soybean; raising broilers and finishing hogs in a concentrated animal feeding operations (CAFO); operating a custom farm business; and hosting an on-farm wedding venue. He has been using cover crops for at least five years, and also markets cover crop interseeders.

Cover it up

Adding cover crops to a no-till system can keep year-round roots in the ground. This system works to enhance soil water retention, decrease weed pressures and herbicide use, increase soil organic matter and carbon sequestration, and prevent soil erosion and nutrient runoff. Cover crops reduce crop stress by conserving water, regulating nutrients and increasing soil biodiversity, Hershey said.

Hershey explained that the goal is to “put as much biomass back into that soil as I can. There are years when you are actually harvesting cover crops now (in late fall) and utilizing it for winter forage. You can still go back and plant another winter cover crop.”

Lucas Criswell farms 1,500 acres of corn, soybeans, wheat, rye and canola in Lewisburg, PA. He has been a no-till farmer for 30 years. No-till farming has greatly decreased soil erosion issues. He now uses cover crops on 100 percent of his acreage. He believes that no-till and cover crops systems are the key to maximizing the profitability and longevity of his farm.

“That living root is huge in allowing things to replenish themselves,” he said. He’s noted that even in very wet seasons, such as 2018, he’s had no compaction problems. Years of no-till and cover cropping have built soil health and he is continually reaping the benefits.

Both Criswall and Hershey have seen a drastic reduction in slug damage in their crops compared to slug pressures in fields where crops are planted into bare ground. Two years ago, Hershey planted a test plot of corn into “down and brown” fields, as well as into a field with a diverse cover crop mix. Slug damage was not a problem in the cover cropped field, while the other field suffered from slug damage. Lucas has seen an increase in ground beetles, which prey on slugs, with the use of cover crops.

Christian Bench, agricultural specialist with NJRC&D, farms sheep and beef on 350 acres in Central New Jersey, where he utilizes no-till and cover crops to build soil health. Cover crops do break the pest cycle, in addition to controlling weeds, adding nutrients and increasing the water carrying capacity of the soil, he said.

As farmers, “you really have to think about the ecosystem under your feet,” Bench said.

While no-till systems, without cover crops, do increase plant residues, it’s the cover crops that add the living roots, attracting microbes that then break down that plant residue. And, as soil structure and health increases, compaction decreases, and the “ground is more forgiving,” Bench added.

Cover crops can also help manage manure. Criswell stated that over the years, he has “learned the value of directly applying manure to the cover crop.”

Studies show that the use of cover crops reduces nitrate levels when manure is incorporated, Hershey said. Incorporation of manure causes a lot of soil disturbance, however. Hershey has conducted experiments to see if there are differences in crop yield when liquid manure is incorporated versus surface applied. He found no yield differences, but incorporation does cut the odor.

“We try to get our manure on fairly early in the spring, so the cover crops can absorb” the nutrients, Hershey said.

Managing cover crops

“Our goal is to keep something living and green in our soil 365 days per year,” Hershey said.

That continual year-round cover is the optimal goal. Hershey, who has been experimenting with cover crops for several years, began with cereal rye and has been adding legumes and brassicas. Ryegrass, oats, hairy vetch, sunn hemp, tillage radish, crimson clover, rapeseed, winter peas and barley have all been utilized in various cover crop mixes on the farm.

Yet these benefits are often overlooked as cover crops can present some management challenges. Planting the cover crop, finding the best-fit cover crop species, and terminating the cover crop can take some finessing. Cover crops can be terminated by killing them with herbicide, by tillage, or by rolling and crimping. But cover crops can also be harvested, either mechanically or by grazing livestock.

For Hershey, getting the cover crop established and managing the spring cover crops have been the biggest challenges. He’s had limited success interseeding the cover crop in southern Pennsylvania, although he knows that farmers in northern regions of the state do so routinely. After interseeding cover crops into corn and experiencing an August kill of the cover crop, he’s surmised that the corn is causing too much shade to keep the cover crop alive. He is seeking ways to improve the success of interseeded cover crops on his farm.

Criswell plants non-GMO soybeans successfully using a no-till and cover crop system and receives a premium. His non-GMO soybeans yield the same as GM soybeans, without the added expense, he said. His sprayer passes are the same, but the seeds cost less. Overall, his profitability is greater.

Criswell decided to harvest some of his cover crops as an additional cash crop. He’s recently harvested wheat straw which was planted into non-GMO soybeans. While he did see some reduction in his soybean yield, he also had another cash crop, and found he broke even when compared to simply planting the soybeans into cover crop residue.

“My goal is how to maximize my farm,” Criswell said. “It’s not about the yield: it’s about the most profitability.”

Grazing the cover crop is another option. Before grazing a cover crop, consideration must be given to any prior herbicide use on the primary crop. Restrictions from grazing due to herbicide use on the cash crop also apply to the cover crop.

“Ruminant livestock cycle nutrients — to put them back into the ecosystem — that plants and microbes can’t,” Bench said. Adding livestock to a no-till and cover crop system is the next step in the system.

Cover crop use builds soil organic matter, and increasing the soil organic matter “improves a farm’s long-term viability and resiliency. At some point, everyone is going to have to focus on their soil health,” Bridgett Hilshey, of NJRC&D emphasized.

2019-02-19T10:34:46-05:00February 18, 2019|Mid Atlantic, Western Edition|0 Comments

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