Weediness and yield of winter wheat depending on the basic elements of farming system

Through the period of 1977-2018, studies were conducted on three experimental fields of the Samara State Agricultural Academy with the purpose of studying the influence of the basic elements of the farming system on the weediness and the yield of winter wheat. Experimental schemes included the following options: the type of fallow in the crop rotation (black, seeded and green-manured), fertilizer systems (organic-mineral recommended, organic-mineral intensive and organic) and various methods and depths of soil tillage of fallow lands. Observations and surveys were carried out according to generally accepted methods. The soil of the plots was ordinary chernozem and typical medium-thick loamy chernozem (humus content was from 6.0 to 8.3 %, mobile phosphorus was from 90 to 155 mg/kg, exchange potassium was from 129 to 190 mg/kg, pHsalt was from 6.3 to 6.8). Replacing black fallow with seeded or green-manured fallow increased the weediness of crops 1.4-1.6 times and reduces the yield of winter wheat by 0.29-1.03 t/ha. Organic fertilizer systems significantly changed the weed species compositions and contributed to an increase in the number of perennials by a factor of 3.0, and their masses by a factor of 1.3-1.4 in comparison with organic-mineral fertilizer system. Organic-mineral fertilizer systems did not have a significant effect on the yield of winter wheat. The organic fertilizer system led to a slight (0.26-0.31 t/ha) grain shortage compared with organic-mineral. The methods and depths of soil tillage did not have a practically significant effect on the weediness and yield of winter wheat.