It's been said there are over 4,700 pounds of actual phosphorus (P) in the soil at any one time, says Brian Banks.
Unfortunately, most of that P is unavailable to plants. Phosphate is not mobile in the soil and can be fixed by other nutrients like calcium, magnesium, iron and aluminum, explains the senior agronomist for The Andersons.
Which is why applying a starter fertilizer may be beneficial for corn.
“There’s a lot of phosphate out there, the plant just can’t use it,” Banks says. “So we want to enhance that with some plant-available forms of P, because only a tiny bit is available at any one time.”
At the 2017 National No-Tillage Conference, Banks explained when a starter fertilizer may be necessary and how to choose the right product for your no-till operation.
While starter fertilizers may vary by formulation and quality, their intention is the same: provide small amounts of fertilizer, particularly P, in close proximity to the seed.
|Salt Index of Some Common Liquid Formulations|
|Formulation||Salt Index||Salt Index per Unit of
Plant Nutrient (20 lb)
|a These grades are formuated using potassium phosphate as the K source.|
b Use in seed-row placement with caution.
c Not suggested for use in seed-row placement. Mortvedt, “Calcuating Salt Index”