Production mean any final harvest of a crop, the harvest products are the resultant of photosynthesis and the multiplication of the cells through mitotic division. For continuing the cell division need to synthesis all necessary biochemicals in every cell cycle prior to division. The cellular synthesis are the binding of amino acids or DNA are the compositions of different CHONP, but for successful synthesizing need some precaursors, elements and cofactors that also plants get from the nutrients like Nitrogen, Phosphorus, Potassium and so on as fertilizers or the inherent sources of soil. When soil is depleted with those chemicals then need to supplement through application as fertilizer. Photosynthesis could not be finalized the photosynthetase and stored as sufficient harvest if any of the necessary nutrients are in shortage.
I support Mr Ujjal Kumar for his wise suggestion. Along with this, I like to add that the element Nitrogen is the most essential elements without which no protein synthesis could be possible for the biotic life and the role of protein is well known to us. Similarly, the metallic element K is also essential for its great role in transport mechanism for fluid from different parts containing valuable ingredients which play various types of biochemical functions not only in crop but also in any biological system.