Abstract
The intensiveness of agricultural systems is given by the sum of the production factors provided per time unit and area. In
this sense, fertilizers represent one of the factors with high variability in the intensification process. In agricultural practice,
in order to maintain high yields, the fertilizers that are commonly applied contain either one or more macro elements (NPK).
In the unifactorial model proposed in the paper, which starts from a Mitscherlich-type model, the constants were determined
and then the concordance was checked between the experimental data and the theoretical data on a wheat crop. Afterwards,
the optimum of the benefit was studied. Subsequently, using a function which generalizes empirically to two variables, good
concordance was also found between the theoretical and experimental data. The optimum benefit was determined by
employing the least squares method in calculating the constants. By hypothesis, the bifactorial model takes into consideration
all three nutritive elements: nitrogen, phosphorus and potassium, but considers them as two independent variables, namely x
for nitrogen and y for the phosphorus-potassium complex in equal proportions.
