How farmers can reduce runoff by 45 percent through nutrient use efficiency
In the current economic and environmental climate, adoption of necessary measures to improve water quality has been slow, especially as the soft commodity market places a burden on the supporters of these measures to prove they’re worth the extra expense. In September of 2016, experts from the public and private sector came together to discuss ways that growers could address water quality issues at the Verdesian Life Sciences Water Quality and Soil Health Solutions panel in Bloomington, Illinois.
Among the panelists were:
- Isaac Ferrie, CCA and agronomist with Crop-Tech Consulting
- Jim Jordahl, director of programs and operations for the Iowa Agriculture Water Alliance
- Trevor Sample, CCA and specialist with the Illinois Environmental Protection Agency
- Mike Wilson, CCA and specialty product marketing coordinator with Wabash Valley Service Company
During the discussion, members talked about research designed to curb nutrient runoff, from tile water studies and tile line gates to wetlands and bioreactors.
“The goals set in Illinois aim for a 45% reduction in total nutrient load by 2025,” says Wilson. “It sounds like a lot, but there’s also a lot we can do to reduce nutrient loss.”
In nitrogen, one of the biggest ways to reduce nutrient loss is by multiple applications, using technology – such as soil and tissue sampling – to decide when to apply to get the most efficient use of nutrients. Another way is by figuring out what we can add to the soil – such as sulfur, calcium, iron – to help corn and wheat metabolize nitrogen better.
“We can’t just get there by reduction; we’ll get there by better nutrient efficiency,” says Wilson. “If we can reduce the Illinois Agronomy handbook’s recommendation of 1.2 pounds of nitrogen per bushel of corn to just .9 pounds per bushel, we’ll blow that 2025 goal out of the water.”
However, reducing phosphorus is a little more complicated. Legacy phosphorus takes a while to recede from the waterways and ditches where it currently sits from previous growing seasons.
“Any time you’re finding nutrients in a waterway, the farmer isn’t getting paid for that,” says Wilson. “If it’s in the ditch, that’s money spent that isn’t making corn, beans and wheat.”
With phosphorus, banding is recognized as the most efficient way to prevent loss, but it isn’t always the most practical. Many growers make one application every two years – enough at once for both corn and soybeans. One method to prevent loss might be to split the application, using enough for each individual crop and keeping it from having an extra year to move offsite into surface water via soil erosion.
And similar to nitrogen, it’s important to consider how interactions with soil pH, zinc, calcium and other micronutrients could affect the ability of phosphorus to hold in the soil and better metabolize in the plant.
“If there’s more in the soil, there’s more chance of loss,” says Wilson. “We’ve got to consider the cost effectiveness of feeding each crop individually.”
Wilson says that, ultimately, the success of these measures will be a team effort.
“Environmentally, the water quality issue isn’t going away,” says Wilson, “and no one depends on the land, air and water more than the farmer.”