by Sally Colby
At a recent meeting of the Pennsylvania Forage and Grassland Council held in Lancaster, PA, Dr. Chris Teutsch, University of Kentucky Extension forage specialist, addressed the issue of rising fertilizer costs.
Fertilizer prices over the last 18 months have nearly tripled, putting pressure on both livestock and row crop operations. Low-input enterprises such as cow/calf operations are especially feeling the pinch.
Teutsch provided 10 tips to help forage producers and graziers get the most from fertilizer.
Tip #1: There are no silver bullets. Teutsch said when fertilizer prices rise, products making unreasonable performance promises tend to appear. In most cases, such products aren’t worth the money. “Some biologics show potential,” said Teutsch, “but the only biological product we’re recommending is inoculant for legume seed. We know that works consistently and is beneficial.”
Tip #2: Continue to soil sample pastures and hay fields and develop effective fertilization management for both. Soil sampling quantifies soil pH, phosphorus (P) and potassium (K) but doesn’t quantify nitrogen (N). “It’s hard to measure available nitrogen in the soil,” he said, “so we make nitrogen recommendations based on past research data.”
Soil sample results provide a guide for accurate fertilizer application. “This is not the time to be putting on a 10-10-10,” said Teutsch. “We want to target exactly what you need.” He suggested graziers combine samples from no more than 20 acres of a pasture and avoid sampling areas where animals congregate (hay rings, ponds, shade, mineral feeders) to get a more accurate sample. Take 15 to 20 cores for a good sample, mix cores in a plastic bucket and submit the sample. “Always use a soil probe,” said Teutsch. “You don’t get as good a sample with a trowel.” Sampling depth is important – four inches is average.
Tip #3: Apply lime according to soil test results. “Never apply lime blindly,” said Teutsch. “We can’t look at a pasture and determine the soil pH and the lime requirement. Now is a good time to apply lime because lime costs have remained relatively stable.” He added that in the eastern U.S., soil acidity is a major factor impacting forage production – acidity reduces nutrient availability and reduces nitrogen fixation in legumes. “Lime neutralizes soil acidity, makes nutrients more available and supplies calcium and magnesium,” he said. “We like to see soil pH between 6 and 6.4 to create an environment that encourages growth of legumes.”
Tip #4: Don’t apply P and K if test levels are in the medium range or higher. Teutsch said fertilizer prices will eventually moderate, but with current high prices, applications should be limited.
Tip #5: Implement rotational stocking rather than continuous stocking. “We get about a 30% increase in productively when we switch from continuous to rotational stocking,” said Teutsch. “The increase comes from resting pastures and increased utilization of available forages.” Nutrient distribution improves in rotational systems, which helps plants recuperate and remain productive.
Tip #6: Capitalize on hay nutrients. “With the current cost of nutrients, one ton of hay contains $85 of nutrients,” said Teutsch. “There’s a lot of value in nutrients and sometimes we don’t do a good job capturing that value.” He suggested feeding hay on the poorest pastures, moving feeding points, using a hay ring to reduce waste or incorporate bale grazing with individual bales distributed throughout the pasture, fenced off until needed.
Tip #7: Incorporate legumes as an integral part of grass systems. Teutsch said nitrogen fixing is an important process, second only to photosynthesis. “This increases yield and forage quality of the pasture, increases protein and has a positive impact on animal performance,” he said. “Legumes can also help dilute the negative impact of endophytes in tall fescue.” He explained research at the ARS Lexington unit showing that a compound in red clover reverses the negative impact of toxins in tall fescue. “Toxins cause vasoconstriction, which leads to problems with animals cooling themselves in summer,” he said. “The isoflavones in red clover cause vasodilation.”
Adding legumes to a pasture is not equivalent to adding N fertilizer. Grazing animals are an important part of the cycle as they deposit most of the N back onto the soil surface in manure.
Tip #8: Frost seed clover in late winter/early spring. Frost seeding takes advantage of the freeze/thaw cycles that cause cracks in the soil surface, allowing seed to work down into the soil. “This works best with red and white clover,” said Teutsch, “not so much with alfalfa and grasses. Alfalfa isn’t as shade tolerant as clover and has a hard time getting established.”
For frost seeding, Teutsch recommended six to eight pounds of red clover with one to two pounds of ladino (white) clover. “Reduce the amount of plant residue on the soil surface by grazing pastures hard and close during winter to expose as much soil as possible,” he said. “Make sure there are adequate freeze/thaw cycles to help incorporate the seed.” If possible, broadcast seed and leave animals on pasture. Hoof action from animals along with them nipping down early growth of existing plants helps limit competition and allows seedlings to establish.
Frost seeding should be done with high quality seed deposited at the correct seeding rate with even distribution. “When you’re broadcasting seed on pasture with a four-wheeler, it’s hard to see where you’ve been,” said Teutsch, “and that can cause misses and overlaps.”
Tip #9: Manage N applications. Nitrogen is only a good investment if forage will be utilized. “One of the problems with grazing systems is there’s growth and too much forage of one kind in spring,” he said. “If we put nitrogen on the pasture, the problem becomes worse. In grazing situations, I limit spring nitrogen applications and apply nitrogen in fall to stimulate growth.” However, N application to hay is desirable because the growth will be utilized.
Due to high N cost, Teutsch recommended application at the lower end of the range provided by the soil test. It’s also important to time N application with plant growth so plants actively grow when it’s applied – otherwise the N is subject to loss through leaching or denitrification in wet spring pastures.
“Pastures can develop a strong nitrogen cycle,” said Teutsch. “In a well-managed grazing system with legumes, we don’t get the nitrogen response we expect because the nitrogen cycle is strong and the pasture is less responsive to nitrogen fertilizer.”
Tip #10: Monitor hayfields closely. Nutrient removal is much higher in a hay production system. “Apply fertilizer only if soil values drop below medium,” said Teutsch. “Feed hay on fields if it’s an option because it allows nutrients to return to the system.”
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