Peculiarities of formation and regulation of potential weediness of different technobiogenous systems

In the agriculture of the Ukrainian Steppe was increased the potential weediness of chernozems in the arable soil layer of vegetative and seed reproductive organs. The soil is considered to be pure, in the arable layer of which there are less than 1 thousand/ha of roots perennial and 10 million pcs./ha of germinative seeds of annual weeds. Due to the excessive potential weediness of soil in bare fallows and in sowing of row crops during the vegetative period, it may appear on 1 m² to 1.5‒2.0 thousand shoots of annual and 15‒30 sprouts or shoots of perennial weeds. Analysis of the state of potential weediness of soils of different pedogenesis and ecological and technogenic history showed that human interference in ecological and landscape complexes in the form of agricultural activity is accompanied by a significant increase in the reserves of weed seeds in the soil. Active soil tillage in crop rotation on the old arable lands is accompanied by accumulation in the layer of soil 0‒30 cm to 452 million pcs./ha of weed seeds. Analysis of the state of potential weediness of soils of different pedogenesis and ecological and technogenic history showed that human interference in ecological-landscape complexes in the form of agricultural activity is accompanied by a significant increase in the reserves of weed seeds in the soil. Active soil tillage in the crop rotation on the old arable lands is accompanied by accumulation in the layer of soil 0‒30 cm to 452 million pcs./ha of weed seeds. The danger of high degree of potential weediness is also increased by the fact that in each layer of a profile section of ploughland, a significant amount of seeds is retained, which in any case creates a risk of high harmfulness of weeds in connection with vertical migration. In the upper most active layer of soil 0‒10 cm concentration seed is 133 million pcs./ha. In the long fallow lands of agrotechnical dormancy the potential weediness in the upper layer of soil is 6‒7 million pcs./ha. In deeper layers are observed only residual signs of the presence of weed seeds. Consequently, the degree of potential weediness on cultivated lands is 20‒50 times higher than in zones of natural development of succession. Potential weediness is a major factor determining the degree of crop weediness, the harmfulness of weeds and the amount of crop loss. The determination of the yielding capacity of the field crops showed that the systems of basic soil tillage on the plots fertilized with mineral fertilizers together with the crop residues were equivalent to all pproductivity indexes: grain yield, grain units and feed units and digestible protein per hectare of crop rotation area with a slight tendency to decrease the indexes for small (mulching) system of soil cultivation. In the variant with crop residues without mineral fertilizers, the system of mouldboard and differentiated soil tillages had advantage over all productivity indiexes in consequence of the better phytosanitary state of crops. By results of research, the highest increase from mineral fertilizers by productivity indexes were characteristic of a small (mulching) background with a more severe nutrient regime. Relative to the farm system of cultivation. The mineral fertilizers used here in moderate doses increase the productivity of crop rotation by more than 14% compared with the production system with better initial conditions of mineral nutrition (system of mouldboard cultivation).