A correct balance between macronutrients and micronutrients is essential to obtain the best results possible from wheat crops. A deficiency of any single nutrient is enough to limit crop yield and the availability of each nutrient needs to be related to the crop requirements. A review of nutrient uptake and offtake reveals which nutrients are required at which growth stages together with the role of each nutrient.
Liebig's law of the minimum, often simply called Liebig's law, states that growth is dictated not by total resources but by the scarest resource which becomes the limiting factor (Justus von Liebig, 1873). This is often depicted as Liebig's barrel where the individual staves in a barrel represent nutrients or other limiting factors.
A nutrient management plan should be focused on achieving the correct balance of the essential nutrients for optimal growth. That does not mean applying all 13, but correct use of diagnostic / analysis tools should be made to understand which of these 13 minerals is at yield limiting supply levels.
One approach to maintain the soil nutrient status is to calculate the removal in the harvested crop, and ensure that these nutrients are replaced over the rotation cycle. The following table is a guide, but more accuracy can be achieved through actual laboratory analysis of harvested material.