IMPROVING THE FERTILITY AND STRUCTURE OF SOD-PODZOLIC SOILS IN CROP-ROTATION

The effect of four eight-crop rotations with different repetitions of perennial grass-legume crops on the physical aspects of soil fertility is discussed. The effect of the frequency of grass crops in a rotatio n on the structure and resistance of the plow layer was demonstrated. It was concluded that soil structure affects the amount of energy requ ired to till the soil. It was demonstrated that, to eliminate the nega tive effect of various factors on soil structure, manure should be app lied or soil-improving crops should be included in the crop rotation n ot less often than once every 4-5 years. It is suggested that the most fertile soil from the physical point of view has a structural compact ness equivalent to that of soil following harvest of a winter grain cr op.