Gypsum and composted materials can have a place in no-till nutrient strategies.
By Frank Lessiter, Editor
With a proper combination of soil moisture, pH, microbial activity and total nutrient supplies, many no-tillers need less fertilizer.
A good example is Mike Starkey at Brownsburg, Ind., who has been making routine soil testing pay off in the family’s 3,300-acre cropping operation. He finds boosting corn yields by just 1 bushel per acre easily pays for the soil test.
By improving soil structure and making more effective use of available soil nutrients, Starkey has been able to dramatically reduce applied fertilizer rates.
Starkey Farms was a winner of a 2009 “Responsible Nutrient Management Practitioners” award from Agro-Culture Liquid Fertilizers and No-Till Farmer during last winter’s National No-Tillage Conference.
Fertilizer Strategies. While nitrogen rates are close to 0.75 pounds per bushel of anticipated corn yield, Starkey expects to reduce the rate further with improved soil structure and higher soil organic matter levels. No nitrogen is applied in the fall.
“We’d like to get to where we apply all of our nitrogen with the no-till planter and eliminate sidedressing trips,” he says. “Last year, sidedressing took us until July 1 to complete.”
Other ways in which the family is looking to trim fertilizer costs include taking a closer look at nutrients other than nitrogen, phosphorus and potassium. There’s increased emphasis on cover crops to provide low-cost nutrients and soil amendments and other minerals to improve crop efficiencies.
COMPOST MIX. Lamb Farms composts a mixture of gypsum, horse manure, turkey manure, wood shavings, sawdust and other recycled products in 500-foot long windrows that each hold 300 tons of material.
As an example, gypsum has proven to be an excellent way to improve both soil structure and nutrient use. When soil tests were done on 225 acres several years ago, 96 acres tested too high in magnesium. Following a gypsum application, this was slashed to only 8 acres.
Starkey applies 1 ton per acre of gypsum every second year at a total cost of $20 to $26 per acre. He continues to use high-calcium lime to control soil pH.
“Some rented land was high in magnesium and as hard as a rock,” he says. “Besides applying gypsum, we limed nearly every acre and increased the rainwater infiltration level from 0.3 to 1.7 inches per hour.”
Magnesium Worries. Ron Chamberlain, the manager of Gypsoil in Indianapolis, Ind., says elevated magnesium can be a concern.
To bring magnesium levels down, he created a gypsum product named Gypsoil.
“This product allows the soil to get more oxygen, increases plant rooting, reduces compaction, improves drainage, boosts microbial activity and helps the soil soak up more water,” he says. “It can also help flush out unwanted aluminum and magnesium.
“No-tillers are finding that they can change the structure of the soil with better control of both magnesium and calcium.”
Containing roughly 20% calcium and 16% sulfur, Gypsoil is produced from recycled gypsum and synthetic gypsum recovered from electrical power plants.
It can be applied with a lime spreader. The recommended rate is 1,100 to 2,000 pounds per acre.
Composting Works. Don Lamb grinds drywall scraps from construction sites and power plant gypsum byproducts for use in a composted material that is applied to a portion of the family’s 7,000-acre no-till, strip-till and conventional-tillage operation. This family operation at Lebanon, Ind., is big on recycling.
The gypsum is mixed and composted with horse manure, turkey manure, wood shavings, sawdust and other recycled products. This mixture is composted in 500-foot-long windrows that each hold 300 tons of material.
“We chisel in the composted material in the fall at a rate of 5 tons per acre,” says Lamb. “Incorporating the material in the spring doesn’t work for us, but the weather makes every year different.”
Lamb is still testing the value of gypsum. “We’re trying to see where it fits, as it is very labor intensive,” he says. “We want to see what our magnesium and calcium levels are before we jump on the gypsum bandwagon.”
Lamb didn’t give the compost much nutrient credit until he studied the soil test results.
“We haven’t purchased any phosphorus since we started composting turkey manure,” he says.