Shevchenko M. Scientific substantiation of ways of weeds harmfulness regulation in agrocenosis of cereals and oil–yielding crops in Steppe zone of Ukraine

The object is the processes of the weed harmfulness regulation in crops of corn and oil cultures. The purpose is to work out the ways of the limitation of spreadness and weed harmfulness reduction based on the new methods of soil cultivation and herbicides. The methods are the field, laboratory and laboratory–field experiments. The results are theoretical basises of minimization of soil cultivation and weed phitocenosis forming, the mechanisms of estimation and weed harmfulness regulation by means selection of effective herbicides which secure of lowering 92–97 percent of weeds are worked out. The novelty is soil cultivation in crop–rotation, the ways of the potential littering destroying, agrophisical parameters of minimization, the competition mechanismes in agrocenosis, the system of selection of the herbicides phitocenotic effect. The incultation is the area of 1080 thousant hectare, increasing of maize, winter wheat and sunflower productivity on 2,1–4,5 centner on hectare.