Which of these elements come under the category of "Primary Macro-nutrients"?
Nitrogen
Phosphorous
Potassium
Primary macro-nutrients are essential elements required by the plant in large quantities. Nitrogen, phosphorous and potassium are the elements that come under this category as they are most often the limiting factors from a crop production standpoint i.e, deficiency of these elements limits plant's health, yield, and growth. Any fertilizer that is made consists of these nutrients without fail. Calcium, although it is extremely important, comes under secondary macro-nutrients.