Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
of fertilizer in the seed furrow (pop-up) or 2 inches below and 2
inches (2x2) to the side of the seed can enhance early plant growth,
especially in cool soil situations. Soils tend to warm more slowly under
no-till and reduce tillage systems where there is more plant residue.
At a 2x2 placement, there is minimal risk of any plant injury. Placement
of fertilizer directly below the seed increases the injury, especially
with limited soil moisture or with some fertilizers that may release
volatile ammonia, such as ammonium thiosulfate.
Placing fertilizer with the seed (pop-up) has the greatest risk of injury, but can be done safely at low rates. The primary concern is with the amounts of nitrogen (N) and potassium (K2O) being applied. General guidelines from several land-grant universities are to limit the total amount of N + K2O to 5 lbs/acre for sandy soils to 10 lbs per acre for clayey soils. At 3 gallons per acre a 9-24-3 fertilizer supplies 4 lbs N + K2O per acre and a 10-34-0 fertilizer supplies 3.4 lbs N per acre. Therefore, in sandy soils the rate of liquid pop-up fertilizer should be limited to about 5 gallons per acre, whereas in loam and clay loam soils up to about 8 gallons per acre can be used.