The key difference between DAP and NPK fertilizers is that the DAP fertilizer has no potassium whereas the NPK fertilizer contains potassium as well. The term DAP refers to diammonium phosphate, and it is a phosphate fertilizer; the world’s most common phosphorus fertilizer. Thus, we produce this fertilizer using two important constituents in the fertilizer industry; phosphoric acid and ammonia. NPK fertilizers, on the other hand, are an important source of nitrogen, potassium, and phosphorus. These are the three primary nutrients that the crops need for their growth and development.