There are very extensive databases of foliar analysis for a large number of commercial crops, e.g., Plant Analysis Handbook IV

That data base is largely for samples from the US and based on commercial crops. Consequently, the 'sufficiency' levels for some elements reflect their high natural concentrations in the soils. A good example is Ca.

Soil analysis is only a rough guide.

The combination is powerful.

The Nutrient (N, P &K) should be applied as a basal dose based on soil test. If soil is deficient in the nutrients, apply 40 kg /ha and 40-60 kg/ha P2 O5 in tall and dwarf, respectively with 20-30 kg K2O and 20 kg sulphur per hectare. Fertilizers should be applied 4-5 cm away from the seeds. The amount of each nutrient needed is called the nutrient requirement. These are different for each nutrient and vary between individuals and life stages, for example women of childbearing age need more iron than men. Some fertilizers also contain certain "micronutrients," such as zinc and other metals, that are necessary for plant growth. Nitrogen is the growth element that promotes green, leafy growth. As a primary component of proteins, nitrogen is part of every living cell. The most meaningful definition of critical nutrient concentration for efficient growers is the level of a nutrient below which crop yield, quality, or performance is unsatisfactory. In spring wheat, 2.0-3.0% N, 0.26-0.5% P, and 1.5-3.0% K in the whole plant prior to filling are considered sufficient as attached table. The 17 essential nutrients are hydrogen, oxygen, carbon, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, chloride, iron, boron, manganese, zinc, copper, molybdenum and nickel. Some of these nutrients are supplied by soil, water and air – while others need to be supplemented with the use of fertilizer..

Start with a soil test to assess the nutrients which are in deficit and look for toxicities while taking in consideration pH and soil organic matter and the soil physical state and if there is profile compaction issues.

Consult this information with experts and get their interpretation.

Together assess a field experiment which could show how the situation might be remediated and design a simple level input trial to find a useful application rate.