Paul Davis preaches the virtues of soil improvement from no-till, never-fallow farming as part of his job as New Kent County Virginia Extension Coordinator. He practices what he preaches at his family farm near West Point, Va.
With fertilizer costs, especially nitrogen, at record prices, Davis is determined to demonstrate that improving soil quality can dramatically decrease nitrogen requirements for grain crops.
“We have been in continuous no-till on our family farm since 1999. We know we are improving soil quality and using less nitrogen, but it’s a slow process. We want to jump start the process and reduce the number of years it takes see input costs go down and yields stay high,” he says.
Davis points out that Virginia grain farmer Randolph Aigner has been in continuous no-till for 12-14 years. In that time frame the organic matter on his farm has slowly increased from 1 percent to 1.5 percent to nearly four percent.
“We are hoping to demonstrate some ways to cut that time frame so growers can take more immediate advantages of no-till farming systems,” Davis says.
On the Coastal Plain soils at his family farm, after years of conventional-tillage, organic matter averaged about 1.4. Since going to no-till they are close to reaching their first goal of 3 percent to 3.5 percent using a combination of no-till and cover crops.
In one 40 acre field the innovative Virginia Extension agent looked at rye, vetch and a combination of rye and vetch as cover crops for a rotation of pumpkins, soybeans and corn.
At the end of the study he hopes to know more precisely how much nitrogen is available to small grains from the vetch cover crop.
In the interim, results are positive, he says. “Last year in pumpkin fields where we planted vetch we used only the standard 65-70 pounds of nitrogen and had a great crop. In fields with rye only as a cover crop, we had to come back with an additional 40-50 pounds of nitrogen per acre,” he says.
The combination of vetch, plus getting organic matter up near 4 percent, he hopes will significantly reduce nitrogen use in soybeans and corn. “We know we get about 250 pound of nitrogen uptake from the cover crops. If we can make half that available for grain crops planted into the stubble, we will be able to save significant money on fertilizer,” Davis contends.
The carbon to nitrogen ratio for rye is about 50:1, compared to less than 20:1 for vetch. It is clear, Davis says, that vetch breaks down quickly and releases high rates of nitrogen. Keeping nitrogen in the soil and making a high percentage of it available to subsequent crops is the trick.
To many small grain growers vetch and rye are dirty words because of their persistence in grain crops. Davis used a combination of gramoxone, 2-4,D and a plant growth regulator to burn down vetch and manage the escapes. He also planted Liberty Link corn, which provided yet another safeguard for vetch control.
“Glyphosate, gramoxone, none of the usual burndown herbicides will take out vetch,” he says. “To be successful a grower must have Bicep or some other plant growth regulator in the mix. In our 40-acre test field, the combination did an outstanding job of controlling rye, vetch and the rye-vetch combination,” he adds.
Davis says one of his goals is to use a starter fertilizer in corn — something like a 30 percent blend of UAN at 40 pounds per acre. Once organic matter is high, he hopes the cover crops will provide all the additional nitrogen his corn crop will need.
The veteran Virginia Tech Extension agent is also looking at different application methods for nitrogen in hopes of one-day using high tech GPS-guided, variable rate nitrogen application.
In his 40-acre test field, Davis used a Red Ball 1410 nitrogen injection rig to place nitrogen about 2 inches deep in the soil. He compared this application to the tradition method of dribbling nitrogen over the soil. He used rates of 40-80-120 and 160 pounds of nitrogen per acre.
Though the crop has not been harvested, Davis says there is a noticeable visual advanatage of the soil injected nitrogen at various rates. The surface applied treatment will lose some nitrogen to volatilization, some to leaching and soil microbes will take a share of it as it works its way down to the root zone.
Another goal he says is to never be fallow — to keep something green on the soil all year round. With the increased interest in double-crop beans behind wheat in the past couple of years, growers are finding ‘never fallow’ is a tough goal to meet. Getting a cover crop in behind double-crop beans is tough, Davis admits.
The state of Virginia offers an incentive program for farmers to use various cover crops. To take advantage of the cost sharing money, growers must get most cover crops in by Oct. 1.
“We want our system to work without the cost sharing money, That’s why we are taking this study to the next level, using high tech equipment like the Red Ball applicator, Greenseeker tissue sensor and ultimately GPS guided, precision applied variable rates of fertilizer,” he says.
Though they grow pumpkins as part of the 40-acre test, Davis says the cover crops, soil applied starter fertilizer and other production techniques would work just as well on more traditional crop rotations, such as wheat, corn and soybeans.
A big advantage of growing pumpkins in the vetch/rye stubble, he says, is keeping the Halloween treats clean. He says they never have to clean mud, not even dirt from the pumpkins, which grow nicely sitting up on the cover crop mat.
As fuel and fertilizer costs continue to soar, growers are going to look for innovative ways to cut input costs. The secret to never-till/never-fallow, Davis knows is to cut the time frame back from 10-12 years to 7-8 years.
A host of production factors in addition to costs seem to be coming together to force more and more growers to look at lower cost options to conventional-tillage practices. The whole arena of herbicide resistance is a major player as more and more materials lose activity on a broader scope of weeds and grasses.
Innovation often comes from desperation, and risks involved in growing high value, high input grain crops will likely force more and more growers to look for new, efficient cost-saving production practices, like never-till/never-fallow.
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