Compilation of a law of the cumulative action of the growth factors and plant productivity by E.A. Mitscherlich

The article presents a brief analysis of the main provisions of the “law on the cumulative influence of growth factors'", proposed by a major theorist and experimenter of the agronomic science, Professor E.A. Mitscherlich (1909). The method of E.A. Mitscherlich has been used so far and is still widely used in the different countries for mathematical processing (evaluation) of the results of laboratory, plotting and field experiments on the effect of various types and amounts of fertilizers on different plants, determining the content of nutrients in the soil and the need for fertilizer in the soil, and studying the dissolution, and adsorption of fertilizers in the soil, determination of the specific surface area, and soil structure during irrigation, etc. The method of E.A. Mitscherlich made it possible to determine the maximum possible yield of the different agricultural crops and to find possible reserves of nutrients in different soils, for different conditions, in many cases (more than 30,000 field experiments). Calculations using the method of E.A. Mitscherlich led to a good match of experimental and calculated data. The article proposes a new method for assessing the effect of crop yield and yield factors based on the following statement: yield and yield growth increase with an increase in the amount of growth factor and are proportional to the amount of the crop that has not reached the (maximum) limit value and the possible value of the crop, above a certain minimum (initial) value. For practical purposes, in the article, approximate formulas are obtained that allow us finding the value of the coefficient of action of growth factors on yield, the amount of nutrients in the soil, and the functional dependence of the crop yield under the action of specific growth factors. The proposed mathematical model of the effect of growth factors on the yield (productivity) of agricultural crops is more general than the well-known law of the effect of growth factors on productivity proposed by E.A. Mitscherlich. The article considers examples of calculations that show a good match between the experimental and calculated data.