The contribution of Dmitry Pryanishnikov to the development of domestic agrochemical science

Practical agrochemistry in its modern form — from calculating nitrogen application rates to gypsum application in solonetz soils — is based on the scientific work of Dmitry Nikolayevich Pryanishnikov (1865–1948). The scientist proved the exceptional role of ammonia as both the initial and final product in the transformation of nitrogenous substances in plants. He managed to clarify the role of asparagine and refute the idea of it being a primary product of protein breakdown. Research has shown that asparagine is synthesized from ammonia, which is formed at the final stage of protein degradation or taken up from external sources. These findings provided the scientific justification for the large-scale production of ammonium salts and their application in fields.

Fundamental works such as "Theory of Fertilization," "Plant Chemistry," "Nitrogen Metabolism in Plant Nutrition," and "Protein Substances and Their Transformations in Plants in Connection with Respiration and Assimilation" provided a scientific basis for methods of mineral nutrition. Under the researcher's guidance, key issues of soil nutrition and fertilizer application were worked out in detail. New methods and approaches were introduced into agricultural practice:

• evaluation of domestic phosphorites as a direct source of phosphorus and raw material for the industrial production of superphosphate;
• physiological characteristics of domestic potash salts;
• study of various forms of nitrogen and phosphorus fertilizers;
• technologies for liming acidic soils and gypsum application in solonetz soils;
• use of green manure (sideration), peat, manure, and other organic fertilizers;
• scientific justification for methods of top dressing and application of various types of fertilizers;
• methods for studying plant nutrition: the method of isolated nutrition, sterile cultures, flow solutions, as well as agrochemical methods of soil and plant analysis.

The "Learning through Research" principle and personnel training

The development of practical agronomy is impossible without systematic education and the training of scientific personnel. Back in 1914, the scientist wrote: "If a sufficiently dense network of higher education institutions covers Russia, if the secondary school system provides broad access for all the most gifted children of the people to higher education, then what a quantity of dormant forces and wasted talents will be revealed in our fatherland?" Academic education was never contrasted with scientific work. The educational process was structured in such a way that independent research by students occupied a central place in learning.

Guided by the principle that scientific work both illuminates and warms, while academic work without scientific work only shines, the scientist formed the motto of his activity: "Learning through Research." The main guide for many generations of practitioners became the textbook "Agrochemistry," which went through a series of reprints in 1934, 1936, 1940, 1946, 1952, 1963, and 1965. This book formed the foundation of the national agrochemical school.