Combine Cover Crop Seeder cuts costs and boosts yields in Virginia fields

In the fields of Charles City County, Virginia, brothers Aaron and James Black are transforming farming practices with their innovative Combine Cover Crop Seeder. Their ingenious system allows them to simultaneously harvest their crops and plant cover crops, significantly reducing application costs and boosting yields.

Aaron and James, who manage N.S. Farms in Charles City, Virginia, oversee 400 hectares of land where they grow a variety of crops, including corn, soybeans, cereals, and sorghum. A few years ago, they envisioned a more efficient method for planting cover crops that would save time and reduce the number of tractor passes required. This led to the development of their Combine Cover Crop Seeder.

Aaron (left) and James Black manage N.S. Farms in Charles City, Virginia. Photo: N.S. Farms

“Time was our biggest challenge,” James explains. “With over 33 fields spread across three counties and a 14-mile radius, moving machines back and forth was logistically impossible. So, the Combine Cover Crop Seeder was the perfect solution to target those fields, that we otherwise wouldn’t be able to cover crop.

“A desire to enhance soil health and improve productivity at the same time also motivated the brothers. “Cover crops and their root systems are a primary component of any improved microbial soil health system”, James says. “The Combine Cover Crop Seeder allowed us to fill a gap, and be more productive in some fields. In the long run, it leads to a whole host of plant health benefits, and higher yields.”

Cost-effective

Developing the system involved extensive trial and error. “We had this grand idea but needed to figure out how to make it work,” Aaron recalls. “This was a necessity. And it really worked fantastic. Once we had a functioning prototype, we were thrilled with the results – good germination and healthy cover crop growth.”

“We thought we were onto something when we looked back to what this basic machine had done”, James notes. “We had cover crops, and didn’t do anything but put the combine in the field. From there, it was full steam ahead with the development.”

We estimate it saves between $15 and $30 per acre on application costs

The system, the brothers built on their farm, is modular, and can be moved across platforms of different manufacturers. It injects the cover crop seed into the chaff stream before exit of the combine, so it gets mulched in with any chaff leaving the combine. That puts a blanket of moisture protection over the seed, and it greatly improves germination.

The combine-mounted seeder has proven to be cost-effective. “We estimate it saves between $15 and $30 per acre on application costs,” James says. “Additionally, it allows us to establish cover crops earlier, which can lead to substantial increases in biomass. We’ve seen up to four times more green biomass by spring compared to planting cover crops later.”

Figuring out what your dirt needs

James explains the importance of timing: “Generally, every 2-week delay can reduce growing degree days by 160 to 300. Early planting can significantly impact biomass and root structure, making those early days crucial.”

N.S. Farms grows various cover crop species, including vegetables, cereals, and clovers. “Growing cover crops has taken a strong hold in our practice profile in the United States”, James says. “The number of varieties available to us is almost endless.”

Intensive cover crop management is crucial, James stresses. “We want to get our cover crops planted on time, and in as many places as possible. We also look at the species that are available, and try to blend those to get the maximum benefits from a soil health perspective. Sometimes a multi-species blend is most beneficial.”

“It’s another step in the direction of regenerative agriculture”, Aaron says. “With warmer weather you can use a certain species, and later you can transition to a different species that does better then. So, you’re actually figuring out what your dirt needs.”

The Combine Cover Crop Seeder saves between $15 and $30 per acre on application costs. Photo: N.S. Farms

30 to 50 bushels per acre more

The improved soil living system, increased nitrogen fixing, and the ability to retain more moisture, have resulted in great yield benefits, the brothers emphasize. “We had cases, in a maize crop, where we have seen 30 to 50 bushels per acre more behind a good cover crop”, Aaron points out.“

And with soybeans, we’ve seen 15 bushels difference. So, we are not only able to see that $15 and $30 per acre savings on application costs, after the cover crop, we’re getting that higher yield as well, adding to our bottom line.”

The original prototype of the Combine Cover Crop Seeder featured a manual switch in the cab to turn on the system, James explains. “But with the help of Precision Planting, the system was automated. The shut-off for the seed control works like any other section control. When you are in a previously applied area, it will shut-off. It relies on a GPS-signal and computer controls to do that.”

The Black brothers currently use a John Deere 9760 combine fitted with their seeder system but have adapted the system for various makes and models. “One of the strengths of our system is its flexibility,” Aaron says. “We’ve already installed it on different machines for family and friends in our county area.”

Picking up steam

The system also supports variable rate seeding, and improvements are ongoing. “With all great things, you can never stop improving”, Aaron says. “But we have reached a point, where we are very happy with what we have produced. Fundamentally, the mechanics are secure. We are working with Precision Planting to streamline the data-integration a little bit more, and viewable on multiple platforms. Precision Planting will also offer support through their dealer network, when we are ready.”

The Combine Cover Crop Seeder has had a significant impact on N.S. Farms, saving $30,000 annually in application fees and fuelling ongoing research and development. Aaron: “It’s been exciting to be a part of that process. From an overall health perspective of our business, it’s been a wonderful thing.”

What’s next for the Combine Cover Crop Seeder? “We hope to take it as far as it will go”, Aaron says. “We’re just getting started and hope to expand further. We expect to have enough research data soon to demonstrate this is a viable alternative. And we’re exploring potential manufacturing partnerships. It’s picking up steam faster than we thought it ever would…“

“By planting early, you are not only getting more biomass, and therefore usually more benefits for the next cash crop, but also aiding in keeping your nutrients on the farm”, Mary Michael Lipford Zahed emphasises. Photo: Sustainable Chesapeake

New Study: Combine-mounted seeder enhances cover crop biomass and reduces nitrogen loss

Preliminary data from a current study indicates that after 1 year, the combine-mounted seeder shows potential to produce equal or greater cover crop biomass compared to drilling 2-4 weeks post-harvest, depending on rainfall.

Planting cover crops at harvest, using a combine-mounted cover crop seeder, also has several other benefits. It can reduce nitrogen leaching post-corn harvest, allows for earlier cover crop planting after soybeans, and saves time and money for growers.

Mary Michael Lipford Zahed, a Virginia Tech M.S. student from the Eastern Shore Agricultural Research and Extension Center (AREC), is collaborating with Sustainable Chesapeake on the study. The study explores whether planting cover crops at harvest with a combine-mounted seeder, rather than waiting 2-4 weeks post-harvest, enhances the cover crops’ ability to capture soil nitrogen. The research aims to determine which seeding method, timing, and species yield the most effective cover crops in terms of biomass production and soil nitrogen uptake, and whether incorporation is necessary after using the combine-mounted seeder.

The study compares early planting during corn and soybean harvests with late planting, which occurs 2-4 weeks after harvest. It evaluates the combine-mounted seeder with incorporation (minimal tillage, only after corn), the combine-mounted seeder without incorporation, and drill. The cover crops used in the study include cereal rye, hairy vetch, and a mix of both.

Preliminary results suggest that using the combine-mounted seeder at corn harvest can increase biomass production by 2.5 times compared to drilling 4 weeks after harvest, depending on rainfall (2421 lb/ac for drilled mix versus 6181 lb/ac for combine-seeded mix). There was no significant difference in biomass production between incorporated and unincorporated treatments after corn, which is a positive outcome as it eliminates an extra field pass, according to Lipford Zahed.

Despite a late-season drought following soybean planting, the combine-mounted seeder produced a statistically similar amount of biomass to drilling 2 weeks later. “Since drilling is considered the gold standard for late-season planting, these results are very encouraging”, says Lipford Zahed. “After 1 year, the combine-mounted seeder shows potential to produce equal or greater cover crop biomass compared to drilling 2-4 weeks post-harvest.

”Planting cover crops at harvest, using a combine-mounted cover crop seeder, can also reduce nitrogen leaching post-corn harvest, allows for earlier cover crop planting after soybeans, and saves time and money for growers.

Previous research highlights that early planting is crucial for maximising cover crop benefits. Studies show that each 2-week delay in planting results in a loss of 160-300 growing degree days (GDD), significantly reducing nitrogen capture when fewer than 550 GDD are available before winter dormancy (Sedghi & Weil, 2022).

Another study indicates that cover crops should be planted by or before October 1 in the mid-Atlantic region to optimise fall nitrogen uptake (Ritter et al., 1998). Delaying planting until November for broadleaf cover crops does not reduce nitrate leaching compared to no cover crops, and early planting is critical for effective cover cropping, especially for brassicas (Dean & Weil, 2009). “So, by planting early, you are not only getting more biomass, and therefore usually more benefits for the next cash crop, but also aiding in keeping your nutrients on the farm”, Mary Michael Lipford Zahed concludes.