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Farmers voluntarily implement practices to reduce nutrient runoff in Chesapeake Bay
It’s a tricky proposition. Virginia farmers need to continue producing the quality agricultural products necessary for feeding a growing global population—and many do that in direct proximity to the nation’s largest estuary and its watershed.
Farmers have embraced this paradox by implementing a host of agricultural best management practices intended to reduce nutrient runoff and restore the health of the Chesapeake Bay. And they’re doing it voluntarily, for now.
If agriculture does not meet court-mandated nutrient load reduction goals by 2028, practices may become mandatory for livestock farmers, and for anyone managing nutrients on their farm.
Thousands of farmers have taken the initiative, doing their part with support from state and federal agencies. Between 2002 and 2021, 35,531 BMPs were installed in sensitive areas, fencing 12 million linear feet of streams and reducing 336,177 annual pounds of nitrogen, according to the 2022 Chesapeake Bay and Virginia Waters Clean-up Plan.
On their own terms
Cattleman Jim Riddell put his conservation beliefs into action, fencing off streams, creating buffers, installing waterers, cover-cropping pastures and rotationally grazing a 150-head cow-calf operation at Georgewood Farm in Louisa County.
“I’m committed to this partnership, and so are the other 23,000 cattle operations across the state in improving their farms and protecting the water with practices that are sustainable long term,” said Riddell, a government affairs specialist with the Virginia Cattlemen’s Association.
His commitment to farm conservation is now rooted in a deeper purpose—four young grandsons, likely his farm successors.
He takes full advantage of loan and cost-share programs available through the Virginia Department of Conservation and Recreation and his local soil and water conservation district.
“If you are going to stay in family farming, you need to be taking part in these programs,” he said. “DCR and local SWCD staff are extremely helpful and unobtrusive, and the incentives are there. If you have ideas for improving your farm, sit down with these guys. I guarantee 90% of what you’re trying to do can be part of the project.”
Fourth-generation crop farmer Jim Evans of Accomack County said Evans Farms shifted to no-till in the ‘90s. Since then, BMPs have helped them retain even more nutrients.
“Here on the (Eastern) Shore, we’re low on organic material in the soil,” he said. “Anytime you have higher levels of organic matter in the soil, you hold on to more nitrogen and water.”
Planting rye, wheat or barley cover crops within crop rows builds organic matter in the soil through winter and eases weed pressure.
“Even though there’s a dead crop there, it’s shading the ground,” Evans explained. “Plus, that cover crop has leftover plant residue that breaks down and releases nitrogen. And the actively growing crops will take it up!”
Side dressing breaks up nitrogen applications, so excess residue isn’t leached away. That’s his daughter Claire’s job.
“She runs through the corn on the sprayer,” Evans said. “By the time she’s back again, the corn has used what nitrogen we originally put out, so the soil can hold what we’re putting on the second time.”
Both Evans and Riddell have earned Clean Water Farm awards from their local SWCDs.
Eastern Shore Agricultural Research and Extension Center researchers are working to enhance the effectiveness of tried-and-true practices, with new cover crop combinations, planting methods and nutrient management strategies.
Gradients of green are observed across corn plots, indicating levels of nitrogen uptake. Data collected from the greenest plots reflects the success of practices that keep nutrients on the farm.
“Cover cropping has been popular in this region for many decades,” said Joseph Haymaker, a Virginia Tech Ph.D. candidate of soils and nutrient management working in Dr. Mark Reiter’s lab group at the Eastern Shore AREC. “Farmers in the Chesapeake Bay region are the leaders in cover crop usage in this country; however, there is still room for improvement.”
According to the latest U.S. Census of Agriculture, Virginia ranks No. 2 in the U.S. with 38.5% of commodity cropland acreage cover cropped.
Mary Michael Lipford, a master’s degree student in Reiter’s lab group, is conducting a no-till study with an array of cover crops and combinations, planted with varying methods. Cover crop species can be used separately
or combined in a mix to best fit a farmer’s goal.
“Rapeseed is a brassica with deep taproots that can obtain nitrogen from lower soil horizons,” she explained. “Cereal rye is a grass good at scavenging nitrogen and creating biomass for weed suppression. Hairy vetch is a legume that fixes nitrogen from the atmosphere, spreading wide and leaving the nitrogen containing biomass for the following cash crop.”
Her project is simulating the effects of combine-mounted seeders that seed cover crops while simultaneously harvest the cash crop, doubling the farmer’s savings in time and fuel. Earlier cover crop establishment will allow for better mitigation of remaining soil nitrogen that may otherwise leach into the watershed after harvest. It also provides increased biomass production,
which adds more organic matter.
Haymaker is working on a multi-state project that has developed a cover crop nitrogen calculator (covercrop-ncalc.org) using data collected from 28 states.
“It gives you nitrogen release curves based on real in-field data for different cover crop species,” he said. “Based on the data we have generated, farmers can estimate how much nitrogen they will be getting back for their following cash crop and when that nitrogen will be available.”
He’s also conducting crop management research on a long-term cover cropping study using 12 different crop rotations, now in its ninth year.
“Every third year, all rotations are in corn, so we apply variable nitrogen side dressing rates to really gauge the impact cover crops have on corn yields,” he said. “Some rotations need more nitrogen and some need less as compared to the standard Virginia system.”