The article tries to develop the method for defining the requirements of fertilizers for soil. The chemical soil analysis is also seen as the requirement for exact site classification based on height over age. The study is based on 1500 soil samples, one half of them from forest soils, the other half from arable land soils.
The productivity of different forest types and the results of soil analyses are in line with each other. The most important growth factors are discerned. Some shortcomings of the method are discussed. Combining the soil analysis and the plant analyses of the sample plots seems to give the most accurate about the amount of nutrients that are available for the plants.