By Scout Nelson
For farmers, picking the right dry phosphorus (P) fertilizer is often limited to what's available locally. In places like Minnesota, the usual choices are mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP), with others like triple superphosphate (TSP) and Crystal Green also available in some spots.
MAP and DAP differ in chemical makeup due to their ammonia and phosphate components. MAP makes water slightly acidic, while DAP makes it more basic. MAP is better for alkaline soils, while DAP is suitable for high pH soils. However, crops generally don't prefer one over the other, so farmers shouldn't worry about choosing MAP over DAP or vice versa.
TSP is a phosphate-calcium fertilizer that is not nitrogen-based like MAP and DAP. It can make solutions acidic more than MAP, making it a good option for fall planting in areas where nitrogen isn't needed. TSP mixes well with other fertilizers and is just as good as DAP in terms of phosphorus content.
Crystal Green, a by-product from factories and water treatment plants, is an eco-friendly alternative to MAP, DAP, and TSP. It is made of struvite, magnesium, ammonia, and phosphate, and is less strong than MAP due to less phosphorus. Crystal Green dissolves less in water, making it suitable for alkaline soils. However, research does not prove Crystal Green is superior to other P fertilizers.
The choice of MAP, DAP, TSP, or struvite depends on your farm's needs and availability. Understanding the small differences can help make the best choice for your farm's soil and environment.
Photo Credit: istock-cactusoup
Categories: Minnesota, Crops