History of Agrochemistry

First assumptions about the role of mineral substances in plant nutrition

The French naturalist B. Palissy as early as 1563 expressed the opinion that soil is the source of mineral substances necessary for plants: salt is the basis of life and growth of all crops, and manure taken to the fields would have no significance if it did not contain salt remaining in it from the decomposition of hay and straw. If a field is sown several years in a row without applying manure, the crops will extract from the earth the salt necessary for growth; thus the land is depleted of salts and does not yield harvests. These ideas about the causes of soil exhaustion and the need to return ash substances in the form of fertilizers received scientific confirmation only 300 years later.

In 1656 the German chemist I. R. Glauber suggested that the main factor of yield is saltpetre, whose application to soil leads to a significant increase in harvest. He linked the fertilizing effect of manure to the formation of saltpetre. However, the views of B. Palissy and I. R. Glauber were not appreciated — more than 100 years remained until the discovery of nitrogen, and the role of nitrogen in plant life was established much later.

In the manuscripts of the French scientist Lavoisier, published after his tragic death in 1794, the main provisions of the mineral theory of plant nutrition were stated, formulated 50 years earlier than Liebig.

Plants draw the materials necessary for their organization from the air surrounding them, from water, generally from the mineral kingdom.

Lavoisier

In the field of mineral nutrition of plants, some views were set forth in 1789 by Rückert. He noted that each plant requires a special soil composition on which it succeeds best, and that some plants under continuous sowing without interruption greatly exhaust the field. He saw the possibility of eliminating such exhaustion in fertilizers containing the missing substance. Rückert proposed a theory of soil exhaustion close to Liebig's. However, this correct position was not convincing for contemporaries due to the insufficient perfection of methods of soil and plant analysis.

If the theory of root nutrition of plants in the 18th century was not yet substantiated, the role of the atmosphere as a source of carbon for plants was confirmed by the works of Priestley (1775), Ingenhousz (1779) and Senebier (1782), although revealing the mechanism of this process and, in general, the theory of air nutrition of plants, required a long time.

The theory of root nutrition of plants developed by a more complex path. The Swedish chemist Wallerius, despite known works of Palissy, Glauber and other scientists on the importance of mineral salts in plant nutrition, in 1761 suggested that plants feed on humus. He made his assumptions from practical observation of the influence of manure and humus on fertility of soil, mistakenly believing that plants directly assimilate humus by roots, and organic substances of soil are food for plants, while the remaining components have auxiliary significance, for example, promote the dissolution of fatty substances of humus (mela). This theory was held and actively disseminated by the largest German agronomist A. Thaer (1752-1828).

A. Thaer believed that soil fertility depends on humus content and that, besides water, humus is the only soil substance serving as food for plants. Mineral substances within this theory were assigned a secondary role, that is, as substances accelerating the decomposition of humus and converting it into an available form. Since Thaer enjoyed great authority at that time, his views and the humus theory of plant nutrition became widespread.

The German scientist Sprengel — predecessor of Liebig in his book Doctrine of Fertilizers wrote that plants form organic bodies from inorganic substances obtained from soil and air, using light, heat, electricity and water. He paid great attention to the need to return mineral substances lost by soil, since carbon, hydrogen and oxygen plants obtain from air, which unlike soil remains identical in composition. Sprengel considered obligatory the application of bound forms of nitrogen to soil, since most plants are not capable of assimilating atmospheric nitrogen. Thus he created the doctrine on the role of mineral substances for plant nutrition and the need to return them to soil.

The difference between the views of Sprengel and Liebig was that the first considered the main source of carbon for plants carbon dioxide of air, but did not deny the possible use of soil humus by roots. Lacking experimental confirmation, he could not deny this, therefore in this part his views coincided with the humus theory of plant nutrition.

J. Liebig

The humus theory of plant nutrition was refuted after the publication in 1840 of the book by Justus Liebig (1803-1873) Chemistry in Its Application to Agriculture and Physiology, which had enormous significance for understanding the role of mineral nutrition of plants.

The main thesis of Liebig's doctrine on plant nutrition is the exclusively inorganic nature of substances absorbed by the plant. Humus serves as a source of carbonic acid in soil, which accelerates the weathering of silicates and prepares mineral food for plants.

A logical continuation of Liebig's mineral theory of plant nutrition was the theory of fertilization and soil exhaustion, substantiating the need for crop rotation. Liebig believed that all plants exhaust soil, but different crops exhaust soil unequally. Thus the alternation of plants in crop rotation only slows the process of exhaustion, but it will sooner or later occur if soil is not returned what was removed by crops. Since most farms export grain, this means first of all a deficiency of phosphorus substances will occur, whose content in grain is higher than in straw. In turn, straw and hay go for livestock feed and bedding, eventually returning to soil in the form of manure, unlike substances removed with grain.

These views of Liebig on the need to apply primarily phosphates subsequently found confirmation in the ahead-of-time use of phosphates compared with other mineral fertilizers. For the isolation of soluble monocalcium phosphates he proposed treating bones with sulfuric acid. More intensive development of the production of phosphorus fertilizers was received by technology in which phosphorites were treated with sulfuric acid. This technology was first proposed by Lawes in 1843 in England.

Liebig insisted on the need to return to soil those mineral substances by which it is especially exhausted. If these minima are not eliminated, other substances will prove useless. This position received the name "Liebig's law of minimum," although Liebig himself did not use this term, considering this position relative. In the book 55 Theses (1855) he noted:

An element completely absent or not present in the required quantity prevents other nutrient compounds from producing their effect or, at least, reduces their nutritive action.

J. Liebig first formulated the idea of conscious regulation of metabolism between man and nature.

The doctrine of the need for return represents, however one might try to limit its significance, one of the most important acquisitions of science.

K. A. Timiryazev

…Every soil can be considered fully fertile for one or another plant species, say for wheat, only if each of its particles in contact with roots contains all necessary nutrients and moreover in such form that allows roots to assimilate these substances at any stage of plant development, at due time and in proper mutual ratio.

J. Liebig, 1840.

Liebig attached importance to the diversity of the complex of factors influencing harvest, such as the geographical latitude of the locality, its elevation above sea level, annual precipitation, distribution by months, average temperature of spring, summer and autumn, maximum and minimum temperatures during the year, physical, chemical and geological properties of soils. Thus he approached the assessment of fertility taking into account a complex of factors. He was not aware of the role of biological properties of soil, since only 35-40 years after Liebig's death was the role of soil bacteria in the formation of nitrates and other processes established.

Liebig did not conduct experiments with plants, substantiating his positions from general considerations about the circulation of matter in agriculture and the chemical analysis of plants.

J. Liebig due to haste in the practical implementation of his conclusions made several erroneous assumptions. Thus he believed that ammonia and oxidized forms of nitrogen in air were sufficient to provide soil with this element and satisfy plant needs. He explained the enrichment of soil with nitrogen by legumes by the fact that over a long growth period they absorb more ammonia from air and nitrogen coming with precipitation. For this reason he determined the value of manure by the content of ash substances — potassium and phosphorus.

Development of the theory of mineral nutrition of plants

The theory of mineral nutrition was developed in experiments on growing plants on infertile media: water and sand, with the addition of necessary mineral salts. In 1858 Knop and Sachs were able to bring plants, when grown on artificial nutrient media using mineral substances, to full maturation.

The importance of nitrogen in plant nutrition was studied by J. B. Boussingault (1802-1887). From 1836, being professor at the University of Lyon, he studied the balance of input and output of nutrients over crop rotation and determined the role of legumes in enriching soil with nitrogen. A number of his works on studying the circulation of substances in agriculture became the basis for the creation of a new science — agrochemistry. The combination of Liebig's position on the role of ash elements and Boussingault's assertion on the importance of nitrogen allowed the development of the theory of root nutrition of plants.

Boussingault opposed his nitrogen theory of fertilization to Thaer's humus theory. Depletion of soil fertility was linked by him to the removal of nitrogen with harvest. He established that some crops, for example, clover and alfalfa, are capable of enriching soil with nitrogen, which was proved by him through precise agrochemical studies in field experiments in crop rotations. The fact of eliminating nitrogen deficiency in crop rotation at the expense of clover and alfalfa was established by him in 1836-1838. Simultaneously it was shown that the amount of carbon in the harvest does not depend on its amount in manure, and the source of carbon for plants is carbon dioxide of air.

Boussingault conducted precise agrochemical and physiological experiments, emphasizing thereby that to verify a scientist's opinion one must ask the opinion of the plant itself. He is rightly considered the founder of agrochemistry.

Boussingault, besides field experiments, conducted studies on nitrogen nutrition of plants in special vessels, laying thereby the beginning of the vegetation method. He set up a number of experiments on the assimilation of carbon by plants, confirming that carbon dioxide of the atmosphere serves as the source of carbon nutrition of plants. The influence of external conditions on the assimilation of carbon by leaves was studied. These works laid the beginning of the biochemical direction in agrochemistry.

In 1886 the work of Hellriegel on the assimilation of nitrogen by legumes was published. Nodules on their roots were discovered by M. S. Voronin back in 1865, but the connection between them and the assimilation of nitrogen was not established. Hellriegel, conducting a series of experiments, concluded that legumes, developing on soil containing certain bacteria, become infected by them and form nodules on roots, after which they acquire the ability to assimilate atmospheric nitrogen. At the same time legumes accumulate organic matter in soil, but simultaneously are nitrogen collectors. After a good clover stand the soil receives nitrogen and organic matter as much as from the application of 30-35 t/ha of manure.

The development of the theory of plant nutrition became the cause of the use of mineral fertilizers in agriculture. In the middle of the 19th century two mineral fertilizers found use in agriculture: Chilean saltpetre and superphosphate. In 1865 the extraction of potassium salts began in Stassfurt.

M. V. Lomonosov

Mikhail Vasilyevich Lomonosov (1711-1765) — founder of natural science in Russia. In 1753 in his work Word on Atmospheric Phenomena he wrote: The abundant growth of fat trees, which have fixed their root on infertile sand, clearly shows that with fat leaves they absorb fatty nourishment from the air.

He was the first to express assumptions about the origin of humus and chernozem. In the book On the Strata of the Earth he explained the origin of soil humus: There is no doubt that chernozem is not primeval and not primordial matter, but originated from the coexistence of animals and growing bodies over time.

Lomonosov believed that during the formation of humus in natural conditions the same processes occur as in cultivated soils during the decomposition of manure and the formation of arable lands.

In 1765 the Free Economic Society (FES) was established, which in the subsequent 100 years played an important role in the development of agronomic science. Works on issues of fertilizer application were regularly published in the proceedings of the society.

A. T. Bolotov

Andrei Timofeevich Bolotov (1738-1833) — outstanding scientist-agronomist, actively advocated the development and wide use of agricultural knowledge, author of important articles on fertilizing fields and soil fertility. Devoted much time to the study of fertilizers — manure, liquid manure, ash and lime. He wrote that lands in many places do not give good harvests without manure, and there is little manure on farms, since there is little livestock from lack of feed, therefore, to have more of them, one must have fertilizers.

A. T. Bolotov raised the question: …on the use for the benefit of cattle manure in steppe and such places where there is no custom to manure land with it.

Even then he noted that chernozems are exhausted and need fertilizers. In the article On Manure Salts he wrote about the formation of plant-available nutrients from organic fertilizers. A. T. Bolotov paid attention to soil fertility, noting that the first subject of grain farming is the quality of land, one must understand what land is most capable of. He linked soil fertility with the biological characteristics of plants, and recommended determining quality (fertility) by conducting experiments with fertilizers.

I. M. Komov

Ivan Mikhailovich Komov (1750-1792) in 1789 in his book On Agriculture set forth the scientific foundations of agriculture. He wrote that before giving rules how to fertilize each land and how to sow which plant, one must show the principles and sources from which these rules flow.

I. M. Komov described in detail the properties of various soils and gave instructions on determining fertility by morphological and geobotanical features, on conducting chemical and mechanical analysis of soils, on determining the content of clay, sand, lime and humus.

Having thus learned the properties of land, the main task of the farmer is to fertilize poor land and, having fertilized it, try that its goodness is not lost.

I. M. Komov

Much attention was paid by him to issues of liming of soils, the use of ash, peat, manure and other local fertilizers: Lime makes clayey soil not only loose, but also destroys any acid found in clayey land for the most part.

Komov proposed and considered useful to use the agricultural experience of England and other European countries.

A. Poshman

Anton Poshman in 1809 published the book Instruction on the Preparation of Dry and Wet Fertilizers, in which he proposed to use "dry fertilizers," representing primarily ash from burning plants and organic waste. Noting the importance of combining manure and "dry fertilizers," he recommended mixing manure with lime, rubbish, ash, dry fertilizers, that is, preparing composts.

The property of lime can be considered an motivating force of vegetation.

A. Poshman

He owns the idea of preparing artificial mineral fertilizers — the preparation of dry fertilizers from various organic substances. Poshman guessed the importance of nitrogen in plant nutrition, but mistakenly believed that ash attracts nitrogen and oxygen from air, forming saltpetre.

A. Poshman was not a supporter of the idea of universal agronomic techniques applicable to any conditions regardless of local ones.

M. I. Afonin

Matvei Ivanovich Afonin (1739-1810) — first Russian professor who taught a course of agronomy, when in 1770 its teaching began at Moscow University. In the same year at the ceremonial meeting of Moscow University he delivered a speech on the importance of organic matter of soil in agriculture.

M. G. Pavlov

Mikhail Grigoryevich Pavlov (1793-1840) — professor of Moscow University, outstanding figure of the Russian agronomic school. In 1818 he was sent to Europe, where he studied agronomy and worked with A. Thaer, who created the humus theory of plant nutrition.

M. G. Pavlov was editor of the journal Russian Farmer, in which he paid quite much attention to issues of agronomic chemistry. In 1825 he published the book Agricultural Chemistry, and later Course of Agriculture, in which he set forth views on plant nutrition and the use of fertilizers. M. G. Pavlov was a supporter of Thaer's humus theory of nutrition, therefore contemporaries called him "Russian Thaer."

To fertilize land means to make it more fruitful than it is.

M. G. Pavlov

"Land fertilization" allows improving physical properties, eliminating acids, accelerating the destruction of organic substances of soil and increasing fertility. The latter, according to Pavlov, consists in multiplying nutrients in soil or compensating what is stolen from land by growing plants, with the help of organic fertilizers. M. G. Pavlov organized and managed an experimental field and agricultural school, where he implemented his views on agriculture; he became the first organizer of experimental work in Russia.

M. G. Pavlov did not speak about the role of nitrogen, phosphorus, potassium in mineral nutrition, believing that the material for plant nutrition is "chernozem" (humus), water and carbonic acid.

After the publication in 1840 of the book by J. Liebig Chemistry in Its Application to Agriculture and Physiology, the humus theory of plant nutrition was refuted. In Russian this book was published in 1864. With the creation of the doctrine on chemical elements and the chemical composition of plants, the development of the theory of mineral nutrition of plants to its modern understanding became possible. From the 1840s experimental agrochemical study of the role of individual types of mineral fertilizers began.

D. I. Mendeleev

Dmitri Ivanovich Mendeleev (1834-1907) — great chemist, but the range of his scientific interests included agriculture, including agrochemistry. In 1869 at the congress of naturalists in Moscow he delivered a report on agrochemical experiments. His views on the production and use of fertilizers, soil cultivation have not lost relevance to the present. In particular, the following:

1. On setting up experiments to study effectiveness of fertilizers, in relation to various zones of Russia.

In his report On the Organization of Agricultural Experiments at the session of the 1st department of the Free Economic Society (3. IV 1866) he set forth his views:

Experiments… are necessary for us both in order to know more closely the conditions of Russian agriculture, and in order to select from scientific conclusions some advantageous for agriculture. Such experiments can serve not a little in science itself, if conducted by strict methods.

D. I. Mendeleev

D. I. Mendeleev set up experiments in four points of Moscow, St. Petersburg, Simbirsk and Smolensk provinces, but these were full-fledged agrochemical studies with detailed study of soil, its composition, effect on fertilizers, climate. He said that experiments must be scientific, with a program and large replication, and experiments done somehow are rather harmful. Being a supporter of exact experimental science, he believed that exact sciences must be applied to agriculture, conduct repetitions of field experiments and apply mathematical processing of results.

2. On the need for wide use of mineral fertilizers:

The use of artificial fertilizers makes it possible to quickly correct deficiencies of soil, replace manure with various wastes, allows bringing culture to highest perfection despite all soil deficiencies.

D. I. Mendeleev

Soils are exhausted and nutrients must be added to them, but manure is scarce, therefore other sources of nutrients for plants must be found. For this, experiments of the Free Economic Society with mineral fertilizers were set up.

D. I. Mendeleev proposed to pay attention to phosphorus and to "alkaline-potash," that is, potassium fertilizers, as well as the study of forms of fertilizers.

3. On the integrated use of methods of creating harvest. In agronomic science Mendeleev assigned central place to agrochemistry, believing that scientific principles in agriculture spread thanks to the interest of chemists, and the main positions of agrochemical science — return of nutrients, theory of fertilization, theory of nutrition — were derived from chemical research.

D. I. Mendeleev believed that one should not fear soil exhaustion, since future generations will be able to find necessary substances for application to soil. He was a supporter of the wide use in agriculture of manure, nitrogen fertilizers and lime, which in the conditions of the Non-Chernozem zone gave a good result, but underestimated phosphorus fertilizers, which in his experiments acted less effectively.

At the same time D. I. Mendeleev was a supporter of a comprehensive approach to increasing the productivity of agriculture:

I rise against those who preach in print and orally that everything is in fertilizer, that, by fertilizing well, one can also plow somehow.

D. I. Mendeleev

A. N. Engelhardt

Alexander Nikolaevich Engelhardt (1832-1893) — professor of chemistry at the St. Petersburg Agricultural Institute, major public figure of that time. Left a deep trace in the history of domestic agrochemistry, proved effectiveness of phosphorus fertilizers.

A. N. Engelhardt conducted research on the use of phosphorites for the production of fertilizer, surveyed phosphorite deposits in Kursk, Smolensk, Oryol and Voronezh provinces. Thanks to his activity and increased interest in the use of mineral fertilizers in Russia, the development of phosphorite deposits began. In 1868-1869 the first fertilizer plants for grinding phosphorite meal began to work.

In phosphorite meal we have a powerful means for developing our wastelands, which in northern Russia constitute the main mass of lands.

A. N. Engelhardt

The zone of effective application of phosphorite meal, in which sod-podzolic soils predominate, D. N. Pryanishnikov called "Engelhardt zone of phosphorite meal application."

A. N. Engelhardt was the first to consider the question of the use of mineral fertilizers and grass sowing, the combination of phosphorus fertilizers and green manuring for enriching soil with nitrogen.

In the book Chemical Foundations of Agriculture he noted the need to return nutrients to soil removed by plants with harvest, pointing out that with manure only part of the nutrients contained in straw and hay returns to soil, the remaining nutrients contained in grain, livestock, dairy products do not return to soil. He saw the dependence of fertilizer effectiveness on the presence of assimilable nutrients in soil: for plants to grow and yield, it is not enough that nutrient elements be present in the medium, but these elements must be in the form of those compounds which are suitable for plant nutrition.

A. N. Engelhardt strove to create intelligent farmers. His name is associated with the establishment of agricultural experimental work in the north of the Non-Chernozem belt of Russia.

A. E. Zaikevich

Anastasy Egorovich Zaikevich (1842-1931), professor of Kharkov University, first showed that chernozems, despite high humus content, respond excellently to the application of mineral fertilizers.

A. E. Zaikevich created scientific foundations of fertilizer application technology: mechanized local, row application. He paid much attention to the organization of experimental work in Russia, set up experiments with fertilizers, on agronomic techniques, studying the dependence of yield of different plant varieties on fertilizers, treatment of fallows, depth of plowing.

P. A. Kostychev

Pavel Andreevich Kostychev (1845-1895) — educator, studied chernozem soils of Russia. In the work Soils of the Chernozem Region of Russia, Their Origin, Composition and Properties developed the doctrine on factors of chernozem soil formation. Paid great attention to the study of the phosphate regime of soils and the use of phosphorus fertilizers. In the work On Which Soils Phosphorite Meal Increases Yields. Study of Podzol and Causes of Its Improvement by Phosphorite Meal he noted that podzolic soils contain a large amount of organic phosphates.

In 1884 the book by P. A. Kostychev Doctrine of Fertilization was published, in which he criticized the "theory of complete return" proposed by J. Liebig. He noted that soil fertility depends not only on the amount of nutrients in it, but also on structure and other physical properties, linking them with the accumulation of humus.

The views of P. A. Kostychev on the mineralization of organic matter in soils, the importance of the soil absorbing complex, absorbed bases and soil solution, soil structure formation, mobilization of natural reserves of mineral substances basically coincide with modern ideas. He noted that mobilization of natural nutrients of soil does not allow doing without the application of fertilizers.

In the cultivation of agricultural plants it has long been noticeable that all soils from which harvests are obtained over a more or less long series of years are exhausted, that is, begin to bring smaller and smaller harvests.

P. A. Kostychev, 1908.

Kostychev became the first Russian agro-microbiologist, founder of the biological direction in agronomic chemistry, subsequently developed in the works of P. S. Kossovich and D. N. Pryanishnikov.

K. A. Timiryazev

Kliment Arkadyevich Timiryazev (1843-1920) made a great contribution to the development not only of plant physiology, but of all agronomic science. He highly appreciated Liebig's contribution to the substantiation of the ideas of rational agriculture. His positions on the return to soil of nutrients carried away with harvest and on the dependence of harvest on the nutrient in minimum, K. A. Timiryazev called the basic law. The main ways of increasing the productivity of agriculture he considered clover sowing and the application of mineral fertilizers.

K. A. Timiryazev attached importance to biological nitrogen fixation by legumes, and called the possibility of obtaining nitrogen fertilizers from nitrogen of air an amazing result of scientific creativity, promising a sharp turn in agriculture. He spoke for the confirmation of scientific achievements in field experiments on farms, considering this the best means to give the peasant the idea to repeat it on his farm.

The tasks of agriculture, formulated by K. A. Timiryazev, fully relate also to modern agrochemistry. To the main scientific task he referred the study of features of cultivation of agricultural plants, accounting of their requirements to external environment conditions. Studying issues of plant physiology and conducting work on assimilation in a field bordering with physics, K. A. Timiryazev always emphasized the proximity of agronomic chemistry and plant physiology. He struggled against narrow practicality that hinders the depth of scientific research.

Timiryazev was a supporter of the wide use of the vegetation method. He built the first vegetation house in Russia in 1872 at the Petrovsky Agricultural Academy. On the basis of his works methods of isolated plant nutrition (I. S. Shulov), method of flowing solutions (P. S. Kossovich), method of sterile cultures in the laboratory of D. N. Pryanishnikov (I. S. Shulov and G. G. Petrov) were subsequently developed.

In the book Agriculture and Plant Physiology (1937), representing a collection of selected lectures, speeches and translations of the late 19th — early 20th century and dedicated to the teacher K. A. Timiryazev agrochemist J. B. Boussingault, he wrote: If the plant lives well, man lives well; if the plant perishes, inevitable disaster threatens man too.

From this he drew an important conclusion: to feed man, one must feed the plant:

… all tasks of agronomy, if one penetrates their essence, reduce to determining and possibly precisely implementing the conditions of proper plant nutrition.

K. A. Timiryazev

In the understanding of K. A. Timiryazev, the science "agrochemistry" cannot be isolated from related branches of natural science, pointing to its inseparable connection with plant physiology and agriculture, calling plant physiology the daughter of agrochemistry. It was these two directions that determined the progress of agriculture in the 19th century.

Successes of agronomic chemistry, appearance of new methods expand the field of science, but only verification directly on the plant gives full reliability to its explanations and conclusions. Agriculture became what it is only thanks to agronomic chemistry and plant physiology; this is obvious and proved by history itself.

K. A. Timiryazev

Speaking about the interrelation and interdependence of sciences, K. A. Timiryazev draws an analogy: animal physiology — medicine, plant physiology (physiology of nutrition) — agronomy:

Just as animal physiology owes its beginning to medical schools, so plant physiology will to a significant extent owe its development to agronomic schools, and at present agricultural academies, experimental stations, departments of agronomic chemistry are perhaps not the least important centers in which plant physiology develops, especially the physiology of nutrition.

K. A. Timiryazev

K. A. Timiryazev in the 19th century was the first in the world to lecture on agricultural chemistry.

It [agronomic chemistry] has as its subject changes and transformations of matter connected with the growth and nutrition of plants.

K. A. Timiryazev

Agriculture itself K. A. Timiryazev characterized: … nowhere, perhaps, in no other activity is it required to weigh so many diverse conditions of success, nowhere are such many-sided information required, nowhere can enthusiasm for a one-sided point of view lead to such major failure as in agriculture.

Therefore agriculture must be scientific and rational, and it becomes scientific when plant physiology and agronomic chemistry lie at its basis. In the philosophy of K. A. Timiryazev, knowledge as goal is science, knowledge as means is art.

And the art of agriculture, art relying on exact data of science, consists in freeing the plant, and consequently the farmer, from the power of the land.

K. A. Timiryazev

To learn the need of the plant — that is the field of theory; profitably… to satisfy these needs — that is the main concern of practice.

K. A. Timiryazev

Timiryazev laid the foundation of leaf diagnostics of mineral nutrition: Just think, when a plant is hungry, it rings itself to be fed.

He was the first in Russia to study the physiological and biochemical importance of trace elements in plant life, in particular, the influence of iron, nickel, manganese, cobalt and zinc on the transformation of phylloxanthin into chlorophyllin. Subsequently these and similar studies laid the beginning of the agrochemistry of trace elements.

D. A. Sabinin

Dmitri Anatolyevich Sabinin (1889-1951) — studied in detail issues of mineral nutrition of plants and physiology of the root system, its permeability and ability to absorb, excrete and process mineral and some organic substances, laying thereby a direction for the study of mineral nutrition of plants and establishing ideas about the synthetic ability of the root system.

The results of the scientific activity of D. A. Sabinin are set forth in his numerous scientific works, especially valued of which is the monograph Physiological Foundations of Plant Nutrition, published in 1955 after the death of the scientist.

D. A. Sabinin conducted scientific-pedagogical activity, especially during the period of heading the laboratory of plant physiology at VPUA (1932-1941) and the department of plant physiology at Moscow State University named after M. V. Lomonosov.

The ideas of D. A. Sabinin received their development in subsequent studies of I. I. Kolosov, N. Z. Stankov, I. V. Mosolov. His students and followers spoke well of their teacher, characterized him as a charming soulful person, bold scientist-innovator, original thinker and researcher, talented pedagogue, of whom domestic science can rightly be proud.

P. S. Kossovich

Pyotr Samsonovich Kossovich (1862-1915) — researcher and public figure, distinguished by breadth and diversity of questions studied by him, their practical orientation. He confirmed the conclusion of D. N. Pryanishnikov about the ability of plant nutrition with ammonium nitrogen by setting up direct experiments under sterile conditions excluding the possibility of nitrification of ammonium nitrogen, which became the cause of the development of production and wide use of ammonium fertilizers.

P. S. Kossovich established that legumes assimilate free nitrogen by roots and, consequently, the probable place of nitrogen synthesis in plants are roots, on which nodules are located. Studying the assimilation of free nitrogen, he proved that biological synthesis of nitrogen can also be carried out by free-living bacteria — Azotobacter and Clostridium.

P. S. Kossovich showed the different ability of plants to assimilate phosphorus of sparingly soluble forms of phosphates, which depends on the biological characteristics of plants, soil type and accompanying fertilizers.

Studying clover fatigue of soil, he established by vegetation experiments the main cause — deficiency of nutrients in soil, primarily phosphorus and potassium. Application of mineral fertilizers, and especially phosphorus, under clover is a measure of combating clover fatigue.

P. S. Kossovich managed to experimentally solve a practical question for agriculture: biological immobilization of soil nitrogen upon application of straw or fresh undecomposed manure. For this, an experiment was set up with oats and vetch. Application of straw to soil led to a decrease in oat yield, but did not reduce the yield of vetch, which ensured it at the expense of nitrogen of air. Thus, methods of storing manure and using it for fertilizer were scientifically substantiated.

P. S. Kossovich made a great contribution to the organization of the publication of Journal of Experimental Agronomy, which for many years became the only periodical scientific-agronomic journal in Russia. He was also one of the first Russian geochemists. In particular, he owns the work on the circulation of sulfur and chlorine in nature, showed the increasing dependence of the amount of sulfur entering soil from the atmosphere with an increase in the number of plants and factories.

K. K. Gedroits

Konstantin Kaetanovich Gedroits (1872-1932) — student of P. S. Kossovich. Developed methods of vegetation experiment, studied phosphoritization and liming of soil, determined the needs of clover in phosphates, developed the doctrine on solonetzicity of soils. World fame was brought to K. K. Gedroits by studies on the soil-absorbing complex and absorbing capacity of soils, begun by him in 1910 and set forth in the works Doctrine of Soil Absorbing Capacity and Soil Absorbing Complex and Soil Absorbed Cations as Basis of Genetic Soil Classification.

These works, as well as Chemical Analysis of Soils, played an important role in the development of soil science and agrochemistry, in the theoretical substantiation of liming and chemical reclamation of solonetzes.

He advanced the position on the ability of soils to exchange absorbed cations (metals and hydrogen) contained in the absorbing complex, moreover the amount of cations absorbed by soil is equivalent to the amount of cations displaced from the soil solution, and the rate of the exchange reaction is instantaneous.

V. V. Dokuchaev

Vasily Vasilyevich Dokuchaev (1846-1903) — outstanding Russian soil scientist. He wrote that improvement of agricultural culture can proceed by a correct, reliable path with comprehensive study of soils. The main task of studying soils he saw in managing the processes occurring in them, determining fertility, stability and height of yields of agricultural crops.

In his works on classification and assessment of lands V. V. Dokuchaev took into account the process of soil cultivation from the application of manure. In 1892 he wrote the book Our Steppes Before and Now, as a response to the severe drought of 1891 in the chernozem belt of Russia. The book contains an analysis of the causes of drought and a plan of transformation of nature and reconstruction of the farming system of the chernozem belt for obtaining high and stable yields.

The system of measures developed by V. V. Dokuchaev is aimed at regulating water economy in steppe regions. Century-old experience of local inhabitants and scientific studies conducted in the southern steppe show that the chernozem zone undergoes slow progressive desiccation. The main of the proposed measures were: regulation of rivers, ravines and gullies; regulation of water economy in open steppes, on watershed spaces; normalization of the ratio of sown areas of arable land, meadows, forests, water bodies and improvement of soil cultivation system in the steppe zone.

V. V. Dokuchaev achieved the organization of a special expedition, which he himself headed, organized a network of experimental stations, testing in practice the effectiveness of his plan and proposed measures. The complex of measures developed by him was applied taking into account local conditions at the Kamennaya Steppe Experimental Station, now NIIISKh of the Central Chernozem Zone named after V. V. Dokuchaev, which allowed over many years to obtain in the conditions of the chernozem steppe high and stable yields of grain and other crops.

V. V. Dokuchaev also noted the importance of training qualified specialists-agronomists, for which the organization of higher educational-agronomic institutes is necessary. He first showed the role of soil in the life of nature and man. In his doctrine it is considered as a natural-historical body, in which, as in a mirror, centuries-old interactions between dead and living nature, including human activity, are reflected. Therefore domestic and foreign scientists call V. V. Dokuchaev one of the founders of the doctrine of the biosphere.

V. V. Dokuchaev supported the idea of development and advancement of domestic zonal agronomy and spoke against blind following and copying the achievements of agronomy of Western European countries.

D. N. Pryanishnikov

Dmitri Nikolaevich Pryanishnikov (1865-1948) — founder of Soviet agrochemistry, substantiated the theory of ammonium and nitrate nutrition of plants, gave exhaustive recommendations on the production and use of ammonium fertilizers, conducted works on the theory of nitrogen metabolism, substantiated the conditions of effective use of phosphorites on acid soils, laid positions on increasing soil fertility and the use of atmospheric nitrogen biologically in combination with the application of nitrogen fertilizers.

In 1887 Dmitri Nikolaevich entered the Petrovsky Academy, at which he worked all his life. Here he received a master's degree in agronomy (1890), was professor (1895-1948), first in the world in 1896 introduced into the practice of students the setting up of vegetation experiments, substituted director for academic affairs in 1907-1913, and from 1916 became director himself. Until his last days in "Petrovka" he headed the department of agronomic and biological chemistry created by him.

In agrochemistry and the practice of chemicalization of agriculture there is practically no theoretical direction in which the influence of the works of D. N. Pryanishnikov and his students is absent.

He actively promoted the introduction and mastering of all new, advanced, spoke against erroneous positions in science and against what hindered scientific-technical progress in agriculture, slowed the development of production of mineral fertilizers in the chemical industry.

Application of agrochemical knowledge in practice D. N. Pryanishnikov considered as a means of increasing labor productivity. Why was this necessary, if Russia, long considered an agrarian country, exported grain to other countries? The answer to this question in the works of D. N. Pryanishnikov: the matter is not that Russia from year to year gathered high grain harvests, but that it was an agrarian country by composition of population, a country in which peasants ate vegetarian style (description of a prosperous village by S. Yesenin: …on holidays — meat and kvass…). Other countries, such as Germany, bought Russian grain for livestock feed, obtaining 1 pound of meat from 4-5 pounds of grain. The average wheat harvest in 1908-1912 in Russia was 45 poods, whereas in Germany — 140 poods.

D. N. Pryanishnikov noted: Russia must avoid the contradiction between improvement of nutrition of population and export, for which it is necessary to create real surpluses of grain with the help of means of soil cultivation, mechanization or "chemicalization," as the use of mineral fertilizers was then called. Giving due to the first two methods, he chose chemicalization. Subsequently it became clear that the application of fertilizers provides at least half of the increase in harvests from intensive methods.

D. N. Pryanishnikov called not to be inactive and not to wait until plants for binding atmospheric nitrogen are built or until superphosphate becomes generally available, but to act and know that each bush of lupine is, in essence, a miniature plant for the utilization of nitrogen of air, working for free at the expense of solar energy.

In the first years of Soviet power Pryanishnikov called for maximum use of local fertilizers — ash as a source of potassium, calcium and other ash elements; paid attention to proper storage of manure, composting it with peat, use of lime on acid soils.

In connection with the development of Solikamsk potassium deposits D. N. Pryanishnikov and his students conducted a number of studies on the use of potassium salts for plant nutrition. He devoted much time to studying the role of biological nitrogen in agriculture, emphasized the importance of the use of organic fertilizers, organized works on studying the effect of trace elements on plants, proved the equivalence of ammonium salts in nitrogen nutrition of plants to nitrates. He determined the conditions under which ammonium salts do not lead to undesirable secondary effects.

Transformation of nitrogenous substances in plants D. N. Pryanishnikov began with the study of decomposition of protein substances and further transformations of decomposition products. It was known that seeds rich in protein substances during germination form a large amount of asparagine. Pryanishnikov proved that decomposition of proteins is accompanied by the formation of amino acids, from which ammonia is subsequently split off. During germination the formed ammonia binds into asparagine and is converted into a nonpoisonous compound, and asparagine can again be used in processes of biosynthesis. D. N. Pryanishnikov called asparagine "neutralized ammonia." In these works close connections between nitrogen and carbohydrate metabolism were shown. Ammonium nitrate, including ammonium and nitrate ions, he called "fertilizer of the future."

Much labor D. N. Pryanishnikov spent on determining optimal dates, doses and methods of fertilizer application, their placement in crop rotations and fertilization of individual crops.

He took active part in the organization of the Geographical Network of Experiments with Fertilizers and defended the need to increase the share of legume crops, characteristic of fruit-rotation crop rotations, substantially improving the nitrogen and humus balance of soils. He spoke against skeptics who underestimated the effectiveness of mineral fertilizers on low-fertility lands, critics of supporters of the grass-field system — opponents of the development of chemicalization of agriculture in Russia. In 1937 D. N. Pryanishnikov wrote:

As for authors who consider… that they know some secret of obtaining high yields without applying appropriate amounts of fertilizers (and without knowledge of agrochemistry), about these authors one can only say that they vainly consider themselves materialists.

D. N. Pryanishnikov

He called not to confuse the concepts "grass-field system" and "culture of leguminous grasses on fields," defending the expansion of legume crops, especially in conditions of sufficient moisture, and grain legumes — in all agricultural regions of the country.

D. N. Pryanishnikov was the first in the country to begin training agronomists-agrochemists. Became author of the fundamental manual Agrochemistry, gathering long-term world experience of fertilizer application, formulated theoretical foundations of agrochemistry in connection with biochemistry and plant physiology.

Pryanishnikov paid constant attention to agrochemical education, never opposed educational education and scientific work, often quoting Pirogov's statement that scientific both shines and warms, while educational without scientific — only glitters. He built the educational process so that independent research of students occupied a prominent place in education. His motto of scientific-pedagogical activity: By investigating — we teach.

Like most outstanding scientists, D. N. Pryanishnikov could rightly be proud of the large army of his students: practically all domestic specialists-agronomists and agrochemists, to one degree or another, studied under him. In particular academician N. I. Vavilov — great sower, agronomist, plant grower, geographer, ecologist, historian, ethnographer, geneticist, breeder, his works in the field of origin, variability, immunity and ecology of plants are recognized throughout the world.

Under the editorship of D. N. Pryanishnikov 17 volumes of the collection From Results of Vegetation Experiments and Laboratory Works were published. Thanks to his active participation, the Scientific Institute for Fertilizers at VSNKh, the All-Union Institute of Fertilizers, Agrotechnics and Agrosoil Science, and the Central Research Institute of Sugar Industry were organized. His fundamental works, including Agrochemistry and Nitrogen in the Life of Plants and Agriculture of USSR, are still used for training specialists.

D. N. Pryanishnikov liked to quote Herzen — without scientific science there would be no applied science. Agricultural production did not arise thanks to the development of scientific knowledge. This conclusion allowed the appearance of a number of speculative, dogmatic natural-philosophical concepts and ideas far from science.

Representatives of such concepts, relying neither on strict natural-scientific theory nor on careful experiment, are generous with promises, they like to boast of their connection with practice, but care little that, for lack of truly scientific theory, they have nothing to connect with practice.

D. N. Pryanishnikov.

G. G. Petrov

G. G. Petrov developed the theory of nitrogen nutrition of plants; results of his studies were published in 1917 in the book Assimilation of Nitrogen by Higher Plants in Light and Darkness, in which the path of nitrogen transformation in the plant from the moment of absorption to transformation into protein substance is shown in detail.

I. S. Shulov

Ivan Semyonovich Shulov (1874-1940) studied in detail issues of the influence of ammonium nitrate on the assimilation by higher plants of sparingly soluble forms of phosphates, which is explained by the excretion of organic acids by roots. Results of his experiments were published in 1913 in the book Studies in the Field of Physiology of Nutrition of Higher Plants Using Methods of Isolated Nutrition and Sterile Cultures.

He studied: development and morphological features of the root system and above-ground organs under conditions of different nitrogen nutrition; assimilation by higher plants of nitrogen of asparagine, absorption of phosphorus-containing organic compounds, issues of organic root excretions, use by plants of ammonium sulfate (NH₄)₂SO₄.

I. G. Dikusar

Ivan Georgievich Dikusar (1897-1973) — scientist-agrochemist, student and follower of D. N. Pryanishnikov. He conducted his research at VNIUIA and at the plant nutrition station of Moscow Agricultural Academy named after K. A. Timiryazev. Contributed to the development of the theory of nitrogen nutrition of plants; results of studies were presented in the doctoral dissertation Nitrogen Nutrition of Plants and Harvest in 1945. This work was evaluated by D. N. Pryanishnikov, D. A. Sabinin, A. I. Oparin and others, who noted this work as an extraordinary phenomenon in our scientific literature. The scientific positions set forth in the work of I. G. Dikusar were verified and confirmed by precise experiment.

An agrochemist must deal not only with scientific problems, but also with education of other agrochemists who will continue the work of their teachers. It is necessary that our children and grandchildren fall in love with agrochemistry; the future belongs to agrochemistry.

I. G. Dikusar

A. V. Vladimirov

A. V. Vladimirov (1904-1952) made a great contribution to the development of the theory of plant nutrition. Results of his research works, performed by him and co-workers from 1926 to 1946, were published in the monograph Physiological Foundations of Application of Nitrogen and Potassium Fertilizers (1948).

In the book A. V. Vladimirov showed:

1. Conditions influencing the entry of ammonium and nitrate nitrogen into the plant: effect of various cations and anions; features of biochemical processes in individual plants, reaction of the medium, aeration of the nutrient solution, etc.;
2. Influence of various forms of potassium salts on metabolism in plants, on transformation of carbohydrates and accumulation of sugars in root crops of sugar beet, influence of anions on the process of sugar accumulation;
3. Role of ammonium and nitrate nitrogen, potassium and other elements in metabolism, in the formation and accumulation of oxidized and reduced organic compounds in plants.

Theoretical positions developed by A. V. Vladimirov on the correct combination of ammonium and nitrate nitrogen with other mineral nutrients allow influencing the yield of crops and the quality of products.

F. V. Turchin

Fyodor Vasilyevich Turchin (1902-1965) — scientist-agronomist who made a substantial contribution to the development of the theory of nitrogen nutrition and the practice of fertilizer application.

Most important results of his research:

1. Liquid nitrogen fertilizers, for example, aqueous solution of ammonia and ammoniates, give the same effect as solid nitrogen fertilizers; when incorporated to a depth of 10-12 cm they are adsorbed by soil colloids without nitrogen losses.
2. Ammoniation of superphosphate with liquid nitrogen fertilizers gives a product possessing high fertilizer value with good physical properties.
3. Showed that potassium deficiency under conditions of ammonium nutrition leads to abundant accumulation of ammonia in plants, leading to ammonia poisoning and complete death of plants. At the same time the content of reducing sugars in the plant not only does not decrease, but significantly increases. The effect of potassium on assimilation of ammonia F. V. Turchin explains by its influence on the chemical activity of carbohydrates, as a result of which with potassium deficiency the rate of synthesis of amino acids and renewal of proteins slows.
4. F. V. Turchin initiated the use of isotopic and spectroscopic methods of analysis in agrochemical research.
5. Discovered regularities of synthesis and exchange of proteins and chlorophyll in plants, showing that synthesis of proteins begins with the formation of constitutive proteins of protoplasm. Reserve proteins are formed during the transformation of constitutive proteins, which are included in the general metabolism in the plant and continuously renewed.
6. Using the chromatographic method, established the sequence of synthesis of individual amino acids from ammonia entering plants: first alanine is synthesized, then aspartic and glutamic acids, and last basic and aromatic amino acids.
7. Presented a scheme of fixation of atmospheric nitrogen in nodules of legumes.

A. N. Lebedyantsev

Alexander Nikandrovich Lebedyantsev (1878-1941). Together with D. N. Pryanishnikov participated in the organization of the Geographical Network of field experiments, thanks to which the geographical regularity of the action of mineral fertilizers was established, their need in various regions of the country was determined, which served the development of production of mineral fertilizers.

A. N. Lebedyantsev thoroughly studied and first showed the possibility of successful use of phosphorite meal on degraded, leached and thick chernozems, which allowed sharply increasing the yield of agricultural crops on these soils. D. N. Pryanishnikov gave the name to the new zone of phosphorite meal application "Lebedyantsev zone"; earlier the zone of distribution of sod-podzolic soils, into which phosphorite meal was applied, he called "Engelhardt zone."

A. N. Lebedyantsev paid much attention to nitrification as a factor of enhancing ash nutrition of plants.

A. N. Lebedyantsev conducted studies on determining the role of soil drying in increasing its fertility, concluding that in natural conditions the process of soil drying has significance in all processes of increasing fertility achieved by methods of soil cultivation.

F. V. Chirikov

Fyodor Vasilyevich Chirikov (1883-1964) made a significant contribution to the study of the phosphate regime of soils and increasing the effectiveness of phosphorus fertilizers.

Determining the content in plant ash of CaO and P₂O₅, analyzing the ratio CaO:P₂O₅ and comparing these results with the responsiveness of different plants to phosphorus of phosphorites, he concluded that if the ratio CaO:P₂O₅ is less than 1.3, for example, in cereals, plants do not react to phosphorite as fertilizer; if the ratio is greater than 1.3, for example, buckwheat, pea, mustard, lupine, plants assimilate P₂O₅ of phosphorite.

Studying the assimilation by plants of P₂O₅ of soil phosphorites, he distinguished five groups depending on solubility. This methodology was used for the substantiation of differentiated application of phosphoric fertilizers on different soil types and in the study of the phosphorus regime of soils, features of transformation of phosphates in soil during long-term application of phosphorus fertilizers.

F. V. Chirikov studied the processes of transformation of phosphates in soil when using granulated superphosphate and the action of phosphorus fertilizers in crop rotation.

A. V. Sokolov

Andrei Vasilyevich Sokolov (1898-1980) — outstanding scientist-agrochemist, organizer of science and practice of chemicalization of agriculture.

In his book Agrochemistry of Phosphorus (1950) he set forth his views and results of agrochemical research.

Man cannot move, eat, reproduce, breathe and think without numerous processes occurring in his organism in which phosphorus actively participates.

A. V. Sokolov

V. A. Sokolov

A. V. Sokolov pointed to the interrelation of nitrogen and phosphorus nutrition of plants; these elements are part of the same compounds and interrelated in metabolism.

He paid attention to practical issues of application of phosphorus fertilizers, for example, showed the dependence of sugar content in beet and starch — in potato on phosphorus supply, acceleration of development of cucumbers and tomatoes. An increase in the share of legumes in grass mixtures promotes improvement of hay quality by protein content.

He studied the role of phosphates under drought conditions, in which plants poorly use soil phosphates, and therefore need phosphorus fertilizers to a greater extent, which promote growth of the root system and acceleration of plant development.

A. V. Sokolov studied the interrelation of phosphorus nutrition of plants with liming of sod-podzolic soils, noting that plants under soil liming over a long period use much more phosphates than without lime, explaining this by better assimilability of calcium phosphates than phosphates of sesquioxides. Liming sharply reduces the amount of mobile forms of aluminum and iron, promotes decomposition of organic phosphates and hydrolysis of phosphates of sesquioxides, converting them into calcium phosphates.

A. V. Sokolov considered the reasons for the effectiveness of granulated phosphorus fertilizers under local application, explaining this by better supply of young plants with nutrients due to the proximity of fertilizers to roots, reduction of retrogradation of soil phosphates and biological binding of phosphates by soil microbes.

In the works Essays from the History of Agronomic Chemistry in USSR (1958) and Geographical Regularities of Fertilizer Effectiveness (1968) he cites results of studying the geography of action of fertilizers on various soil types.

O. K. Kedrov-Zikhman

Oskar Karlovich Kedrov-Zikhman (1885-1964) made a significant contribution to solving the problem of liming acid soils. In the monograph Responsiveness of Agricultural Plants to Liming in Connection with Soil Acidity and Degree of Soil Saturation with Bases (1934), thanks to conducted studies, he concluded the possibility of wide use of magnesium-containing rocks for liming acid soils, and also showed reactions of crops to soil acidity and composition of absorbed cations after liming.

The use of dolomitized limestones and dolomites for liming doubled the reserves of calcareous raw material. On the topic of the use of magnesium for liming he published works: Importance of Magnesium in Lime Fertilizers (1940), Magnesium and Boron as Factors of Increasing Effectiveness of Liming (1940), Influence of Soil Liming on Size and Quality of Harvest Depending on Content of Magnesium in Lime Fertilizer and Application of Boron (1948).

Special attention O. K. Kedrov-Zikhman paid to the study of the action of trace elements on plants under conditions of liming acid sod-podzolic soils. According to obtained results, boron fertilizers enhance the positive action of lime, boron and magnesium during liming increase starch content in potato tubers, sugar — in beet roots, fat — in seeds, improve their quality. Positive action of cobalt under liming conditions on the yield of most crops was established, an increase in the mobility of molybdenum upon application of lime, which allows reducing the need for molybdenum fertilizers; liming reduces the mobility and availability to plants of compounds of zinc, boron, cobalt, manganese.

Works of Ya. V. Peive, M. Ya. Shkolnik, E. V. Bobko, O. K. Kedrov-Zikhman, A. V. Sokolov, P. A. Vlasyuk, M. V. Katalymov and other scientists were devoted to studying the role of trace elements on growth and development of plants, biochemical processes and conditions of effectiveness of microfertilizers in various soil-climatic zones of the country. In particular, the action of boron fertilizers under liming conditions was studied, high effectiveness of copper fertilizers on peat soils, manganese fertilizers in beet farms, zinc fertilizers on carbonate chernozems, molybdenum — under legumes was established.

I. P. Mamchenkov

Ivan Prokhorovich Mamchenkov (1896-1980) from the time of the opening of VPUA in 1931 for 40 years headed the laboratory of organic fertilizers.

Most important results of his research on organic fertilizers:

1. Various methods of manure storage were studied; it was established that under the aerobic method of storage, to reduce nitrogen losses, manure must be composted with superphosphate and phosphorite meal; most rational methods of storage were developed.
2. Self-heating of peat and peat-manure composts to 60-70° C increases the content of ammonium and easily hydrolyzable nitrogen in them.
3. Composting manure with phosphorite meal increases the rate of its humification, reduces nitrogen losses of manure, increases the coefficient of phosphorus use of phosphorite meal.
4. Various types of bedding were studied; economically most advisable to use for these purposes straw and peat, since nitrogen of peat is mobilized when composting it with manure, liquid manure, with wastes of agricultural and municipal economy.
5. Possibility of using sewage sludge as fertilizer was studied.
6. Advisability of joint application of organic and mineral fertilizers in crop rotation was proved.

Important works on storage and use of manure were also conducted by F. T. Perigurin, M. A. Egorov, I. F. Romashkevich and others.

Issues of application of green fertilizer were actively dealt with by E. K. Alekseev, S. P. Kulzhinsky, V. N. Prokoshev, F. F. Yukhimchuk and others.

Ya. V. Peive

Yan Voldemarovich Peive (1906-1976) — founder of the doctrine on trace elements in domestic agrochemistry. Most significant scientific developments:

1. Developed in 1933-1934 methodology for determining mobile potassium in soils.
2. In scientific works Trace Elements and Enzymes (1960), Biochemistry of Soils (1961), Guide to Application of Microfertilizers (1963) analysis of results of hundreds of field and production experiments with trace elements is given.
3. He headed the scientific work of the laboratory of biochemistry of trace elements, organized by him in 1962 within the Institute of Plant Physiology named after K. A. Timiryazev of USSR Academy of Sciences, where he performed studies on metalloenzymes related to nitrogen metabolism of plants, metal-containing proteins participating in processes of symbiotic nitrogen fixation in nodules of legumes, revealed new links in the process of biological nitrogen binding, which allowed influencing the rate of the nitrogen fixation process by regulating mineral nutrition of plants.
4. For various soil-climatic conditions, the influence of soil reaction, redox properties, organic matter content, liming, application of organic and mineral fertilizers on assimilability of trace elements was studied.
5. Yan Voldemarovich studied the role of trace elements in biochemical processes of plants and in soil.
6. Under the leadership of Ya. V. Peive, methods were developed for determining the content in soil of various forms of trace elements, methods of quantitative determination of soil trace elements.

N. P. Karpinsky

N. P. Karpinsky, on the basis of results of experiments with fertilizers on different soil types, established the dependence of the action of fertilizers on the genesis and degree of cultivation of soil.

Similar dependencies were determined by A. F. Tyulin, P. I. Andrianov, E. N. Raion in studying soil colloids, physical and physicochemical properties of soils, and mechanisms of absorption by soil of cations and anions of salts under different degrees of moistening and drying of soils were established.

N. P. Karpinsky and V. P. Zamyatin established a connection between the concentration of phosphate ions in salt extract (0.03 N K₂SO₄) and the availability of phosphorus for plants.

V. A. Frantsesson

Vladimir Andreevich Frantsesson (1902-1961) conducted great work on studying the fertility of virgin and fallow lands and methods of influencing it in the first years after plowing.

From 1937 he headed the laboratory for studying soil fertility of the chernozem zone, studied water properties in the process of drying and wetting of chernozem soils. Generalized results of these studies were presented in the doctoral dissertation Change of Agronomically Important Properties of Chernozem under Influence of Drying and Wetting (1948). In this work the conclusions of A. N. Lebedyantsev about the increase in mobility of nutrients under the influence of drying and wetting of soil were confirmed, and the connection of these phenomena with the destruction of soil aggregates was shown.

In 1948-1949 V. A. Frantsesson headed an expedition for studying water-physical properties of soils of the Central Chernozem Zone, results of which were published in the work Chernozem Soils, Their Genesis and Properties.

Thanks to scientific and practical results of his activity, the following positions were derived:

1. Cultivation and cultivation of soils is a new stage in the development of agronomic soil science, which must study not only soil types, but also soils created by man, that is, study the genesis of various cultural soils and their properties. V. A. Frantsesson generalized experimental material of soil-agrochemical surveys of the chernozem zone, established a number of regularities regarding the effectiveness of mineral fertilizers depending on properties and cultivation of soils.
2. Study of water-physical properties of chernozem soils showed the importance of measures for preserving moisture and overcoming drought, as the most important measure for obtaining high yields and high effectiveness of fertilizers in non-irrigated regions. Rational use of moisture is possible under the condition of correct application of fertilizers, since the optimal ratio of nitrogen, phosphorus and potassium strongly influences the expenditure of soil moisture. For this reason it is important to establish effective doses, ratio and technique of fertilizer application.
3. As one passes from ordinary chernozems to thick, leached and podzolized chernozems of forest-steppe, the ability of soils to accumulate nitrates decreases; correspondingly, the effectiveness of action of nitrogen fertilizers in this series increased.
4. On soils poor in mobile phosphorus, the effectiveness of phosphorus fertilizers may decrease if not provided with sufficient amount of mobile nitrogen.
5. Low effectiveness of phosphorite meal on soils with high saturation with bases requires development of special measures to increase assimilability of phosphoric acid of phosphorite, for example, application of phosphorite meal with physiologically acid fertilizers; its composting with manure; application of phosphorite meal under crops possessing increased ability to assimilate phosphates from it.

By effectiveness of action of phosphorite meal V. A. Frantsesson distinguished in the Chernozem zone groups of regions:

1. Regions of continuous or predominant distribution of soils on which application of fertilizers is most effective. These include regions of leached and podzolized chernozems;
2. Regions of partial distribution of soils on which application of phosphorite meal is most effective. These include regions with predominance of thick and rich chernozems, as well as regions with leached and podzolized chernozems with increased saturation with bases;
3. Regions where application of phosphorite meal is effective under condition of nitrogen supply, for example, in crops of legumes, upon application of nitrogen mineral fertilizers;
4. Regions where application of special measures is required to increase mobility of P₂O₅ of phosphorite meal. These include territories of distribution of ordinary chernozems with very high saturation with bases (more than 93-95%).

A. T. Kirsanov

Alexander Trofimovich Kirsanov (1880-1941) made a great contribution to the development and introduction of new methods in experimental agrochemistry. Distinguished by a broad outlook; his scientific-methodological developments and positions are still of wide practical importance. Many standardized methods of agrochemical analysis of soils are associated with the name of A. T. Kirsanov.

He paid much attention to the development of methods for determining mobile phosphates, which allowed already in 1931 to issue the first cartograms of content of mobile phosphates in various soils.

A. T. Kirsanov contributed to the theory and practice of liming acid soils, to the explanation of the nature of soil acidity, linking methods of regulating soil acidity with yield, with physical, physicochemical properties of soil, with biological processes, such as nitrification, ammonification, biological absorption of nutrients by soil organisms.

In the second edition of the book Liming as Factor of Yield (1930) A. T. Kirsanov examined in detail the experience of liming soils in foreign countries and methodological approaches to determining the need for liming.

He also studied the problem of the use of potassium and the interaction of potassium and nitrogen fertilizers. Results of these studies were published in works: Chemical Determination of Need of Soils for Potassium Fertilizers (1933), Action of K on Various Soils at Various Concentrations of H, Ca and N (1934), Mutual Dependence of Action of Potassium and Nitrogen Fertilizers (1935), Change in Content of N, P₂O₅, K in Barley Harvest under Influence of Soils and Fertilizers (1938), etc.

Studying the interaction of different types of fertilizers, he in 1934 concluded: with strong deficiency of potassium, nitrogen fertilizers not only do not increase harvest, but even ruin it.

He considered the action of fertilizers connected with the presence of available forms of nutrients in soil, the ratio of ions in the soil solution, moisture and level of fertility, the height of harvests in previous years, features of agronomic techniques and other factors.

V. M. Klechkovsky

Vsevolod Mavrikievich Klechkovsky (1900-1972) — leading researcher in the field of agrochemistry and radioecology, worked on the development of methodology and application of the tracer atom method in agrochemistry and biochemistry. In his studies a special place is occupied by the creation and development of radioecology and agrochemistry of radioactive fission products; results of these studies received world recognition.

In 1947 V. M. Klechkovsky organized the laboratory of biophysics at Moscow Agricultural Academy named after K. A. Timiryazev, in which subsequently worked such scientists as A. G. Shestakov, I. V. Gulyakin, E. V. Yudintseva and others. During the first five years of the laboratory's work, the main regularities of behavior of radionuclides in soil, the magnitude of their transfer from soil to plants and quantitative accumulation in various parts of plants were discovered.

Subsequently large studies were conducted to determine the conditions of entry of radionuclides into plants and factors reducing accumulation in crop harvest. These results remain relevant to this day, especially when cultivating plants on agricultural lands subjected to radioactive contamination. One of the methods of reducing the content of radionuclides in soil is the application of mineral and organic fertilizers.

V. M. Klechkovsky (1900-1972) also dealt with issues of phosphate nutrition of plants, quantitative regularities of action of fertilizers and optimal ratio of nutrient elements in plants.

V. M. Klechkovsky emphasized that in its development agrochemistry relies and will rely on understanding the mechanisms of metabolism and energy down to the deepest levels: submolecular, molecular, subcellular, cellular.

V. M. Klechkovsky and A. V. Vladimirov dealt with the problem of application of slags. As a result of studies it was shown that in the interaction of phosphates with soil processes of exchange absorption and chemical precipitation occur. Absorption of phosphate ions in soils saturated with bases is explained by the formation of calcium phosphates. However, sorption of labeled ³²P was the same even when not calcium but potassium was in the absorbed state in soil. Application of labeled atoms allowed studying the influence of granule sizes, their depth and frequency of incorporation on the entry of ³²P into plants. It was shown that distribution of ³²P among plant organs upon foliar application of phosphorus occurs slowly and unevenly. The method of labeled atoms showed that the coefficient of use by difference is inaccurate, since upon application of phosphorus in rows phosphorus of soil may be used more effectively thanks to better development of plants. Whereas in the presence of easily available forms phosphorus of soil may also decrease.

V. M. Klechkovsky was a student of D. N. Pryanishnikov. He attached great importance to chemicalization:

Chemicalization is a mighty lever of technical progress in agriculture, …it would be a great delusion to hope that chemicalization can successfully develop without simultaneous, and not only simultaneous, but also ahead-of-time development of its scientific basis — agrochemistry. Huge funds are invested in chemicalization. The first duty of scientists is effective scientific substantiation of chemicalization measures.

V. M. Klechkovsky

D. N. Pryanishnikov to the question — who is an agrochemist? — answered: An agrochemist is the best agronomist among chemists and the best chemist among agronomists. V. M. Klechkovsky emphasized that an agrochemist must possess a high level of fundamental knowledge in chemistry, physics, mathematics. Expressing words of gratitude to his teachers, he said that they educated by their example readiness to defend scientific truth, scientific positions and irreconcilability to dogmatism, bookish learning and superficiality. For there is nothing more dangerous for the authority of science than ignorance clothed in pseudo-scientific form.

N. S. Avdonin

Nikolai Sergeevich Avdonin (1903-1979) developed most important scientific-practical positions in agrochemistry; under his leadership at the department of agrochemistry of MSU named after M. V. Lomonosov multi-plan fundamental and applied studies were conducted.

In the early 1950s N. S. Avdonin performed studies substantiating the effectiveness of granulated superphosphate compared with powdered. The reduction of retrogradation of phosphoric acid of granulated superphosphate in soil was explained by activation of microbiological processes in the sphere around granules, which leads to a decrease in chemical immobilization of phosphorus. Results of these studies were summarized and published in books: Granulated Fertilizers and Application of Granulated Superphosphate.

Under the leadership of N. S. Avdonin studies were set up to study the interrelation between properties of soil, use of fertilizers and resistance of wintering crops to unfavorable conditions in the winter-spring period. Study of biochemical reactions occurring in wintering plants on examples of transformations of carbohydrates, nitrogenous substances, ash elements, activity of invertase, catalase, peroxidase and proteolytic enzymes showed that death of plants in winter period on sod-podzolic soils occurs due to the negative impact of unfavorable soil properties and wintering conditions. Results of these works were published in the monograph Issues of Agriculture on Acid Soils.

At the department of agrochemistry of MSU under the leadership of N. S. Avdonin the influence of soil properties and fertilizers on the quality of plant products was studied. Results showed the dependence of quality on cultivation of soil, which was assessed by content of protein substances, essential amino acids, various carbohydrates (glucose, sucrose, starch), vitamins, carotenes, composition of ash substances. After generalization these data were published in the book Soils, Fertilizers and Quality of Crop Production.

N. I. Vavilov

Nikolai Ivanovich Vavilov (1887-1943) — outstanding agronomist-plant grower, geneticist, breeder, geographer, teacher and organizer of agricultural science, founder of the doctrine on biological foundations of selection.

N. I. Vavilov, on the basis of a series of field and vegetation experiments on studying the influence of nitrogen and potassium fertilizers on the immune system of plants, concluded that immunity depends in a complex way on environmental conditions. He confirmed this conclusion in studying the influence on plant immunity of macro- and microelements of new varieties of wheat and oats differing in resistance to brown and yellow rust. Among factors capable of influencing immunity, he included soil acidity.

N. I. Vavilov always followed the doctrine of D. N. Pryanishnikov on agrochemistry as a system plant — soil — fertilizer, emphasizing the important significance of mineral fertilizers for agriculture. Therefore he received with satisfaction the discovery of deposits of potassium and phosphoric salts in Solikamsk and Khibiny. About this he wrote that this posed the problem of chemicalization of agriculture in a new way — from academic study of production of mineral fertilizers on an industrial scale, with its actual absence, the country began their wide use. In his opinion, expansion of production of mineral fertilizers is one of the conditions for further development of agriculture.

On the basis of results of study on the effectiveness of mineral and organic fertilizers, as well as liming of soils in collective and state farms of Leningrad region, he identified regions of most effective application of fertilizers in crop rotations in complex with agronomic techniques. In the article Problems of Northern Agriculture (1931) N. I. Vavilov wrote that the main condition here is chemical reclamation and application of organic and mineral fertilizers, drawing attention to the underestimation of manure.

N. I. Vavilov called for a differentiated approach in application of fertilizers, warned against template application of any measures.

He noted that chemicalization of agriculture in Russia requires conducting systematic research work, jointly with scientists of other directions.

S. I. Volfkovich

Semyon Isaakovich Volfkovich (1896-1980) — outstanding scientist-chemist who made a great contribution to the development and improvement of technologies of production of mineral fertilizers. He headed studies on processing Khibiny apatite-nepheline ores into concentrated fertilizers, fluoride salts and rare-earth metal compounds; participated in the launch of the first shop for ammonia synthesis, in the development of technology for obtaining and conditioning ammonium nitrate.

S. I. Volfkovich initiated research on technology of urea production and was an active supporter of its application. Later he together with co-workers proposed a method of production of phosphates and polyphosphates of urea, that is, a triple fertilizer — carboammophoska.

After the discovery of the largest Verkhnekamsk deposit of potassium salts, he with co-workers proposed technology for processing sylvinites and carnallites to obtain potassium-nitrogen and magnesium fertilizers.

Extensive theoretical and production studies of S. I. Volfkovich, his students and co-workers became the basis for the creation and development of production of defluorinated phosphates, ammonium and sodium phosphates, mono- and dicalcium phosphates, which became widespread as feed additives for livestock.

Back in 1962 S. I. Volfkovich called for increasing rates of production of mineral fertilizers and microfertilizers, determined directions of expanding their assortment and improving quality by increasing concentration of nutrient elements in fertilizers and producing complex mixed fertilizers including macro- and microelements, producing nitrogen and complex fertilizers in liquid form; called for production of chlorine-free potassium fertilizers, for production of slowly soluble nitrogen and complex fertilizers based on products of urea polymerization.

V. A. Kovda

Viktor Abramovich Kovda (1904-1991) — professor of Moscow University, who had a substantial influence on the development of the ecological direction of research in agrochemistry. In works related to agrochemistry and geochemistry, a new direction of agrogeochemical research was created.

In the work Foundations of Doctrine on Soils (1973) Kovda wrote that cultural (artificial) biogeocenoses, directed by reason and labor of man, produce organic products of food and production significance. Obtaining maximally stable biological production from biogeocenoses is possible when man correctly influences the links of this complex system… It is possible to manage cultural ecosystems effectively when the mechanism, essence and history of relationships of soil, organisms and environmental conditions are understood.

Soil fertility is one of the most important conditions of human life on Earth. Optimization of chemical composition of soils by agrochemical means not only increases soil fertility, but also prevents the occurrence of some endemic diseases of humans and animals.

A universal and important result of biological circulation of substances and biogenic transformation of rocks, formation and mineralization of organic substances was the ubiquitous origin on land of the humus horizon. This thin shell of the energetically and biologically most active part of the soil cover determines the level and potential possibilities of fertility.

V. A. Kovda draws attention to the need for a complex of measures for preservation and reproduction of humus in soil:

• systematic application of organic fertilizers;
• crop rotation system;
• inclusion in crop rotations of legume or legume-cereal grass mixtures;
• periodic application of green fertilizers;
• liming.

Natural soil fertility without application of mineral and organic fertilizers even on good soils cannot ensure stable obtaining of grain yields above 2.5-3.0 t/ha. On podzolic, gray forest, drained bog soils without fertilizers yields do not exceed 0.8-1.2 t/ha; on irrigated serozems, chernozems or chestnut soils — 2.5-3.0, but more often 1.5-2.0 t/ha. To ensure yield at the level of 5-6 and especially 7-10 t/ha, it is necessary to create and maintain a favorable biochemical background of soil, high energy supply of soil with humus content 5-6%, sufficient moisture, nutrients and carbon dioxide.

Successes of future agriculture V. A. Kovda linked with application of mineral fertilizers, believing that industrial fertilizers remain and will remain in the foreseeable future one of the main methods of increasing productivity of agricultural production.

One of the tasks of modern agrochemistry is comprehensive increase in effectiveness of mineral fertilizers and simultaneous study of ecological consequences of intensive chemicalization of agriculture… In developed countries, where high-productivity agricultural production is based on intensive application of fertilizers, the latter become an ecological factor enhancing through soil-ground waters, plants and soil microorganisms the circulation of biophilic elements.

V. A. Kovda

P. G. Naidin

P. G. Naidin (1893-1969) became the initiator of the creation and head of the All-Union Geographical Network of Experiments with Fertilizers VNIUIA, author of over 150 scientific and popular scientific works on the use of fertilizers in various regions of Russia, methodology of experimental work, construction of fertilizer system in crop rotations.