The primary purpose of fertilisation is to satisfy the plants’ nutritional needs to the extent that high yields of good quality can be achieved. The secondary function is to maintain an optimum (average) nutrient content in the soil.

Nutrient deficiencies reduce yields and the quality of plant products. Balanced nutrition of all nutrients is essential for the proper development and yield of plants. A lack of any macro- or even micro-nutrient limits yields and reduces the efficiency of utilizing other nutrients.