ABSTRACT
Reviewing the literature on the various soil physical conditions and plant root relations, one can state that the effects of all of the main soil physical factors were studied. Among the great number of publications, the majority are related to three soil factors: water, aeration, and mechanical impedance. The effects of physical conditions on root growth and functions are closely related to climatic conditions, soil conditions, soil management, and the stage of plant development. The pattern of root development is genetically controlled and can be greatly modified by physical and chemical factors in the soil environment and by plant breeding. For a long time, tillage was the most obvious way to improve soil structure for root and shoot growth, but within a few years it was shown that zero tillage or minimum tillage, provided weeds are controlled and germination is not restricted, can be succesfully used in numerous soil types without any decrease in crop yields.
