The law of the combined action of plant life factors in agrochemistry

Every agronomist knows: it is impossible to obtain a maximum harvest simply by increasing the application rate of a single fertilizer or intensifying irrigation. All plant life factors — light, heat, water, and nutrients — work in close interaction. This is the law of the joint action of factors. Maximum return from any agricultural practice is possible only when crops are fully provided with all other resources.

In field trials, scientists have attempted to express this dependence mathematically. It turned out that the yield increase depends on each growth factor and is proportional to the difference between the maximum possible and the actually obtained harvest. Based on the experiments, coefficients for the utilization of individual plant life factors were derived:

• Nitrogen (N) action coefficient — 0.2
• Phosphorus (P2O5) action coefficient — 0.6
• Potassium (K2O4) action coefficient — 0.4
• Magnesium (Mg2O) action coefficient — 2.0 per 1 mm of precipitation

Compensation effect: how nutrition helps to save water

In practice, the joint influence of factors differs from their simple summation. Changing one condition inevitably leads to changes in others. In an optimal combination, the so-called compensation effect comes into play. For example, fertilizer application increases the concentration of nutrients in the soil solution. As a result, plants spend significantly less moisture to create organic matter.

This is confirmed by the results of field experiments with winter wheat of the Bezostaya-1 cultivar. Researchers compared indicators of total moisture consumption and yield on different agricultural backgrounds. The final data clearly illustrate the law of compensation.

Compliance with the requirements of this law is of decisive importance for practice. It is necessary both for obtaining high stable harvests and for the reproduction of soil fertility. A balanced approach allows for the most complete realization of a crop's potential.