In the mid-1970s, Dr. Robert Westerman banded 18-46-0 with wheat at planting in a low-pH soil near Haskell, Oklahoma. The impact was immediately evident. Soon after, Oklahoma State University published an extension brochure titled “Banding Phosphate in Wheat: A Temporary Alternative to Liming” (Figure 1). This method was a temporary solution for the significant amount of Oklahoma winter wheat that was either too far from a reliable lime source or under a short-term-lease contract.
It’s important that producers not overreact to lower crop prices for wheat by cutting back this fall on phosphate fertilizer if it is needed. Wheat is a highly responsive crop to phosphate fertilizers. At low soil test levels, good profits can be made by using the right rate of phosphorus applied at the right time and in the right manner.
Worldwide, most soils and crops require phosphorus (P) additions to improve fertility and production. Directly applying unprocessed phosphate rock to soil may provide a valuable source of plant nutrients in specific conditions, but growers must consider several complicating factors and limitations.
When it comes to phosphate source selection, the menu is a good one. It contains liquid sources, such as the polyphosphates 10-34-0 and 11-37-0; and granular sources such as monoammonium phosphate (also called MAP, which is 11-52-0) and diammonium phosphate (also called DAP, which is 18-46-0).
The production and application of nitrophosphate fertilizers is largely regional, its use centered where this technology is advantageous. The process uses nitric acid instead of sulfuric acid for treating phosphate rock and doesn’t produce gypsum byproducts.