Weed infestation of crops and short rotating crops productivity in the steppe zone

The purpose of the study is to establish the optimal ratio and set of crops in short-rotation crops providing a minimum level of weed infestation and a maximum grain yield. Objectives: to identify the degree and nature of weed infestation in short-rotation crops, as well as to determine the yield of crops after various predecessors. The object of study is 4-field crop rotations: 1) black fallow - winter wheat - spring barley - sunflower; 2) ½ fallow black + ½ peas - winter wheat - spring barley - ½ sunflower + ½ grain sorghum; 3) peas - winter wheat - corn for grain - grain sorghum / sunflower for the 8th year. Control - 7-field crop rotation: black fallow - winter wheat - ½ corn for grain + ½ grain sorghum - spring barley - peas - ½ winter wheat + ½ spring barley - sunflower. The experiments were carried out on chernozem soils of the Rostov and Lugansk Regions. In 4-field crop rotations, in comparison with the 7-field one, the fields were more efficiently cleared of weeds in a grain-fallow crop rotation with a share of pure fallows of 25 %. With a decrease in the proportion of black fallows to 12.5 % and in crop rotations without black fallows, weediness increased. Weeds were suppressed most effectively in winter wheat and spring barley crops, least of all in pea crops. Row crops provided a reduction in weediness only in grain-fallow-row crop rotations. The maximum yield of grain and seeds (4.45 t/ha) was obtained in a grain-fallow 4-field crop rotation with a black fallow share of 25 %. The yield of grain and seeds in other crop rotations was lower by 10.8-22.2 %. The highest productivity of 1 hectare of arable land (4.18 t/ha) was achieved in the grain-fallow crop rotation with a black fallow share of 12.5 %.