ABSTRACT
This chapter discusses the concept of nutrient uptake and efficiencies of applied nutrients. Efficiency is defined as the amount of product per unit input consumed. Usually, fertilizer increases the yield of crops. Agronomic Efficiency is the additional grain yield produced due to application of nutrients over unfertilized control per unit of nutrient applied. Physiological Efficiency is the additional biological yield produced due to application of nutrients over unfertilized control per unit of additional nutrient uptake over unfertilized control. Agro-physiological Efficiency is the additional grain or economic yield produced due to application of nutrients over unfertilized control per unit of additional nutrient uptake over unfertilized control per unit of additional nutrient uptake over unfertilized control.
