Yurkevich Y. Agrobiological backrooms of efficiency increase of various crop rotations and fertility of soil in south Steppe of Ukraine

Agrobiological backgrounds of productivity increase of different crop rotation systems (4-5-6 fields) and soil fertility of the south Steppe of Ukraine are generalised and grounded theoretically, developed and economically confirmed on the basis of rest is long term experimental researches. It is set that crop rotations with optimum saturation ratio and placing of cereal and oil- bewaring crops, unseeded and seeded fallows depending on fertilisation ensure stable groin productivity (spring wheat and barley, corn, peas, seed of oil- bearing crops ( sunflower, spring rape) and increase of agricultural products quality. Іinfluence of various crop rotations and fertilizers on the features of the water and nourishing mode, density of soil, balance of humus and its transformation, activity of curriculum of linen in soil, diminishing of weeds of seeding of agricultural crops and negative influence of deceases and insects are found ate. Value of plants residues tailings and their quality in forming of supplies and balance of organic matter in soil. Grounded out dependence of productivity, economic and power efficiency of various crop rotations, on different situation, ratio and placing of agricultural crops, in depending on fertilization is stated.