The evolutional way of developing of the theoretical and practical basis of main tillage since the middle of the first part of the 20^th century up today is highlighted. Exaggerated ideologization of science, government monopoly of academician V.R. Williams from thirties to fifties years of the 20^th century caused big losses in agrarian science, especially in farming and agriculture sciences. The disaster of Williams was caused by absolute priority of soil conditioning and universalization of developed by him grass rotation system of farming.

Till fifties in crop farming arable tillage to the depth at least 20–22 cm dominated completely. The first person in the USSR to refuse from a plough was T.S. Maltsev who recommended to hold deep beardless tillage once in 4–5 years, and for the rest of the time to use surface one (up to 8 cm) or surface tillage (10–12 cm) with discs. After T.S. Maltsev works, the issues of differentiation of tilled soil layers under beardless and surface tillage became especially controversial. The final boost for the development of theoretical and practical basis of tillage minimization was soil protecting system suggested by the group of scientists of the former All-Soviet Union Research Institute of grain growing headed by О.І. Baraievyi. It was based on beardless tillage, sowing with stubbly seeding machines, flap and buffer planting, snow capture etc.

Early adopters of a full refusal from beard tillage in Ukraine during 80–90ies years were І.Ye. Shcherbak, F.М. Morgun, М.К. Shykula, S.S. Antonets and their students and followers.

Nowadays the majority of national scientists consider the differential different depth tillage as the most effective one during crop rotations, which includes alternation of different ways, events and means of soil tillage depending on ecological conditions, crops biological features, structure of crop acreage, fertilization systems and plants protection etc. In scientists opinion, the minimal tillage is available on 3 millions of hectare and no-tillage is available on 5,49 millions of hectare out of 30 millions of tilled soils in Ukraine.

In thirties V.R. Williams and M.S. Sokolov criticized surface tillage. Academician M.M. Tulaykov who was openly against doctrines of V.R. Williams recommended surface tillage in dry regions which in his opinion had to protect tilled soil from wind formed processes.

He claimed that surface tillage is economically suitable for poor husbandries and that dust storms are the result of a constant daily soil drifting caused by deep tillage.

In forties an American farmer E. Folkner widely promoted surface tillage together with soil mulching with plant matters of green crops.

The first person to refuse from beard tillage in the first part of the 20th century in the Soviet empire was T.S. Maltsev. He proved decisively the advantages of beardless tillage over beard one in Transurals. T.S. Maltsev suggested the whole range of tools for soil tillage developed by him, the main of which were cultrate pulverizers and a beardless plough.

The necessity of tillage with plough was the main stereotype existing in the world tillage theory and practice till the fifties.

Scientific inheritance of M.M. Tulaykov became one of the bases for reconsideration of the concept of V.R. Williams existing in Ukraine.

He concluded that it was necessary to change beard tillage to surface one to the depth 10-12 cm under which root system of one-year-old plants would be decomposed in tight soil where anoxic conditions must dominate. And to cultivate bottom layers it was necessary to hold deep tillage with beardless ploughs once in 4–5 years.

The first person to refuse from a plough in the USSR was T.S. Maltsev. He suggested using surface plowing with disc tillers and deep beardless tillage (40–50 cm) once in 4–5 years instead of tillage in crops rotation of Transural. In 1952 he made a beardless plough for the first time.

The most controversial issue among the scientists of Ukraine was differentiation of the tilled layer and its effect on crop productivity under beardless and surface tillage.

In sixties and seventies O.I. Baraiev and his colleagues from All Soviet Union Research Institute of grain farming headed by him developed for the first time a soil protective system based exceptionally on different depth beardless tillage in crop rotations, usage of stubbly seeding machines, subsurface cultivators, soil spikers, coulisse fallow, buffer planting etc.

In Ukraine during eighties and nineties years a complete refusal from beard tillage in favor of beardless tillage was supported by І.Ye. Shcherbak, F.Т. Morgun, М.К. Shykula, S.S. Antonets and other scientists and experts. High weed infestation of fields under such tillage was the main obstacle to its widespread usage.

In the 21st century the majority of scientists recommend differential different depth main tillage which suggests different ways, events and means of its implementation in crop rotations depending on biological features of crop, soil and climate conditions, fertilizing systems, plant protection etc, 13 millions hectare of tilled soil is technologically suitable for minimum tillage in Ukraine, and the rest 5,5 million hectare do not even need tillage at all.

Key words: tillage, soil, evolution, plough, subsurface cultivator, erosion, minimization, differentiation.