Imagine a 12-acre dairy farm that has operated using farm-scale equipment and the latest technology. The farm represents a typical start-up dairy farm in the Northeast, but the cows are invisible because they’re all on paper.
This farm exists, and the Pennsylvania land is helping researchers and dairy farmers gain valuable insight about how crops and cows are affected by weather, the results of various crop rotations, which pests will predominate during a growing season and pest management in no-till systems. Farmers learn the consequences of certain crop rotations, how a new crop will fit on the farm, and the effects on soil fertility and quality based on management choices – all without having to experiment on their own farms.
Project Promotes Sustainability
The farm is the focus of the Sustainable Dairy Cropping Systems project, developed by a team of Penn State researchers and funded by a Sustainable Agriculture Research and Education (SARE) grant. The project examines a variety of cropping systems that can potentially improve the sustainability of a dairy farm. The system is on real acreage and simulates a 240-acre farm at 1/20 scale. Although the dairy herd is on paper, the animals are managed exactly as their live cousins.
Project leader Dr. Heather Karsten, associate professor in the Department of Plant Science at Penn State University, received a SARE grant to carry out the project, which was initiated in 2010. The project is designed to address and explore on-farm options without farmers having to take the risk. The project plans are based on an “average” size dairy farm that would grow crops to fulfill the dietary requirements for the cows (both forage and feed), allow for manure management and produce fuel for the cropping system.
Karsten explains the goals of the long-term project. “How do we help farmers deal with off-farm input costs and swings in milk prices to minimize those risks? How can we help dairy and other farmers deal with the challenges of optimizing nutrient management to protect water quality? How do we reduce pesticide use on the farm? How can we make dairy farmers less susceptible to the inevitable swings in costs and income?”
With the help of farmers, Natural Resources Conservation Services (NRCS) and Penn State researchers, the team designed two 6-year crop rotations. The dairy herd is managed by Penn State Dairy Nutritionist Virginia Ishler, and includes 65 milking cows, 10 dry cows, 12 calves from birth to 6 months, 20 heifers from 7 to 11 months and 32 heifers from 12 to 24 months. Ishler uses the actual Penn State dairy herd as a barometer to adjust the computer models in terms of how production would be as influenced by weather and other factors.
Cropping System Design Is Multi-Faceted
The cropping system is designed to minimize nutrient and soil loss, build soil organic matter, promote positive biological processes that optimize crop yields and soil health, enhance biological diversity and maintain an efficient, productive and sustainable dairy operation. Double cropping is an important aspect of the system, and helps maximize land use while keeping feed costs down.
Rectangular plots, each one-quarter of an acre in size, are the basis for the model farm. Plots are replicated four times on the site, each representing one year of a crop rotation. All of the crops are grown and harvested using farm-scale equipment, and forage yield and quality at harvest are measured.
Canola Used As Fuel
One unique aspect of the farm is canola grown for both a feed and fuel source. “We extract the oil and it goes directly into a SVO (straight vegetable oil) tractor for fuel,” Karsten said. “The remaining canola meal is a high protein source for the dairy cow ration. The addition of a brassica in the rotation helps establish nitrogen, covers the soil and adds more crop diversity.”
Researchers have discovered that the addition of rye silage to the crop rotation proved to be beneficial to the crop inventory, soil health and cow diets. Rye provides cover through fall, winter and spring, and the root system helps to maintain soil biological activity and soil structure. Covered ground means there’s a place to spread manure in fall, and growing plants capture nutrients from manure that might otherwise enter the watershed. Best of all, rye silage is a good feed for dry cows and heifers. “We don’t want to feed them feed that’s too high in protein, which leads to more nutrients in manure [and] to manure and water management issues,” Karsten said.
When rye was grown as a cover crop and allowed to grow 10 days longer than usual, it provided significantly more biomass for rye silage. Analyses showed that the crop captured more manure nitrogen and prevented excess nutrients from entering water or being lost through volatilization and ammonia loss.
Another experimental crop was clover underseeded into rye. The rye/clover was harvested, and additional feed value was gained through the red clover. The following spring, the clover acted as a green manure. When researchers studied the soil beneath the red clover stand, they found that the hyphae of the Mycorrhizal fungi, which form a symbiosis with the root system and help take up phosphorus, water and nitrogen.
Karsten says that in most years, by the time corn grain is harvested, there isn’t time to establish a cover crop. In an effort to provide continuous cover, the team used an interseeder in June at the time sidedress nitrogen would be applied to plant a mixture of crimson clover, red clover, annual ryegrass and orchardgrass in grain corn. By early October, the cover crop was viable. After the corn grain was harvested in fall, the cover crop continued to grow and was sufficiently established to continue growing in early spring.
One year, when an alfalfa planting failed, the team planted sorghum sudangrass. “That helped us realize that there are a lot of benefits to using that forage in the system,” Karsten said. “It was great when the summer was hot and dry, and it’s better forage for dry cows and heifers. If we want to optimize nutrient balance on the farm, we don’t want too much protein in the dry cow and heifer feed that will end up in the manure.”
Manage Manure to Yield High Nutrient Value
Manure that’s produced on a dairy farm must be carefully managed to optimize nutrient value without adding excess nutrients to the soil. Karsten said that in three out of four years, liquid dairy manure applied at a rate of 4,5000 gallons per acre in spring resulted in a pre-sidedress nitrate test that showed no additional nitrogen fertilizer was necessary. “The red clover and the dairy manure provided all of the crop’s nitrogen needs,” she said, “and reduced the need to bring in nitrogen for the next corn silage crop.” The amount of manure produced by the herd is a known factor, and that amount was actually applied on the model farm.
In manure application trials, nitrogen and phosphorus in manure was better preserved through injection than in surface-applied manure. “Less ammonia is volatilized, there’s less phosphorus on the surface that can run off, and odor is reduced,” Karsten said. “Odor reduction helps with neighbor relations and also helps increase the likelihood of renewal of land rental contracts.”
Because the farm is managed in a no-till system, the team studied slug control. “We’ve learned over the years that slug activity changes over the season, but peaks in the second week of September,” Karsten said. “They emerge in spring, eat, then burrow into soil when it’s hot and dry and emerge larger in mid-September.” The solution was to plant alfalfa and alfalfa/orchardgrass in early spring, before slugs hatch and before they’re big in the fall.
As dairy herd manager, Ishler receives crop and harvest information and applies it to the virtual dairy herd that is housed in a tie stall barn. Each month, she tracks inventory, formulates diets for each animal group and determines the grain mix costs, then determines income over feed cost (IOFC).
Ishler says that the team assumed that the farm would take out loans for upgrades and capital purchases, and that crops would vary from year to year. She found that the model experienced what any other farm would experience during the start-up years – reduced yields on new stands. “The value of the project is to evaluate sustainability of various practices over time,” she said. “You have to be flexible and know what you’re feeding and make decisions to compensate.”
Cover Photo by lightstalker/istock