IVANOV F. Agroecological grounds and effectiveness of growing corn and winter wheat on a crop rotation plot in conditions of southern steppe of Ukraine.

Peculiarities of vegetation and productiveness of corn for grain and silage, drilled in summer with 210 sms spaces between rows were studied. It is proved that corn, drilled in the second decade of June at the expense of vegetation removal to the period of more favourable weather indices influences plant growth and development. Improvement of mineral nourishment and water-supply regimes is noticed. Critical period of corn plants is in condition of air temperature decrease and increase of its humidity. Corn yield for silage and grain compared to basic crops increases 30%. Growing of summer sown corn with 210 sms spaces between rows allows to use it before harvesting previous crop for sawing winter wheat. Available water reserves in the soil are sufficient for rectiving normal winter wheat shoots. Harvesting corn for silage before the shoots of wheat doesn't influence greatly the state of winter wheat crops. No negative results of harvesting corn for grain from frozen soil are noticed. Growing of winter wheat in corn spaces between rows allows to get stable yield of food grain. Productiveness of crop rotation plots on the whole increases 1,5-1,6 times.