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Carefully approach spring manure applications

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Patience and timing will help maximize the value of manure applied this spring

At this time of year livestock producers may be looking at full manure storage and want to get an early jump on application for the coming growing season.
Patience can pay off in the form of manure nutrient conservation. After all, the goal of manure application is to place valuable nutrients on the soil where they are needed and to keep them there. A large part of this equation is timing.
The closer the nutrient is applied to actual crop need, the better.
Application of nutrients during times of snow cover, frozen soil, or saturated conditions increases risk of nutrient loss. Once a nutrient passes the field edge, it is lost to the environment — and lost from crop uptake.
A fraction of both nitrogen and phosphorus in manure will be present in soluble forms. If the liquid solution of manure can infiltrate the soil, then soluble nutrients will infiltrate with the liquid to a location that is safe from overland runoff.
The ammonium nitrogen fraction will also be safe from volatilization after it is beneath the soil surface. Frozen, snow-covered, and saturated soil conditions hinder infiltration. Spring rain events can carry both the soluble and solid portions of manure from the field.
Farmers who must apply manure before conditions are ideal should go to fields specifically listed in their nutrient or manure management plans to receive manure during the current season.
Some things that limit risk of manure nutrient loss include fields with shallow slopes, fields with a perennial crop such as hay, fields with a cover crop, fields with lots of crop residue, and fields that are more distant to water.
They’re advised to prioritize the order of manure application according to risk and go to the least risky fields first.
Because infiltration can be limited at this time of year, extreme runoff events can occur. For instance, snow melt or rain on frozen or snow-covered ground can cause runoff to occur from lands that rarely lose water.
For this reason, it is wise to skip subtle swales in these fields where water can gather and flow.
Nutrients placed here certainly won’t stick around. These shallow depressions can be covered with manure later in the spring when risk is lower.
Producers should pay attention to the weather forecast and avoid situations where they expect upcoming weather may undo the nutrient placement work they have done.
A new web site gives runoff risk potential and is called the Minnesota Runoff Risk Advisory Forecast located at https://www.mda.state.mn.us/protecting/cleanwaterfund/toolstechnology/r… or Google Minnesota Runoff Risk Advisory.
The goal of manure application is to place valuable nutrients on the soil where they are needed and to keep them there.
 

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