Mobilisation of minerals from the soil and corresponding uptake by the root, are also related to
the quantity of root surface that encounters the mineral. Because plants sometimes grow at rates that are faster than the ability of the roots to absorb and translocate minerals to the critical leaf and or berry tissues, foliar sprays can often help overcome a deficiency or maintain optimum nutritional levels of those critical tissues. Therefore, foliar application can be used as an adjunctive method of plant nutrition.

One definition of balanced fertilisation is the nutrient mix which gives the optimum economic return.