WOOSTER, Ohio – With corn and soybean harvest ahead of schedule in Ohio, farmers are encouraged to make their fertilizer applications now.
"This is a rare opportunity for farmers," said Robert Mullen, an Ohio State University Extension fertility specialist. "With harvest about two weeks early, on average, they can get quite a bit of fertilizer applications down this fall and avoid that frozen ground application in the winter."
Mullen, who also holds an appointment with the Ohio Agricultural Research and Development Center, said that phosphorus and nitrogen are the two main fertilizer inputs made to the soil and extra care should be taken with how both are managed.
"Soil test, soil test, soil test," said Mullen. "Know what your nutrient status is. If you don't need phosphorus, don't apply it. Point blank. End of story. There is no agronomic benefit to applying more phosphorus than is needed."
If a phosphorus application is required, specifically as an input from manure, Mullen encourages farmers to follow best management practice recommendations on application amounts.
"From a water quality protection perspective, if any material is applied in the fall, we would prefer it be incorporated or applied to a field that has a growing crop," said Mullen. "Incorporation allows phosphorus, specifically, to be bound to soil particles decreasing its risk of transport. An active growing crop will have the opportunity to absorb some of the nutrients from the application. Additionally, avoid surface applications if large rainfall events are called for in the short term weather forecast. "
Mullen said that if there is no incentive to apply phosphorus from manure then don't do it, especially if a grower may run the risk of losing any nitrogen over the winter months in the process.
"This may not be the best time to apply nitrogen because of higher soil temperatures and our weather pattern," said Mullen. "If you apply manure now, you may lose a good fraction of that nitrogen when springtime rolls around."
For farmers who may wait until frozen ground to make manure applications, Mullen recommends they follow these tips:
• Make sure there is some field residue to a physical impediment to prevent the fertilizer from running off the field into a water source.
• Minimize application rates from an environmental standpoint. "If you minimize the rate, then you minimize the risk," said Mullen.
• Have a setback distance from any water source, generally 200 feet.
"If you can get into your fields and make fall applications, then some of these may not be a big concern this winter," said Mullen.
For more information about managing fertility in no-till, log on to http://ohioline.osu.edu/agf-fact/0209.html.