The exclusion of mechanical tillage leads to the concentration of seeds on the surface under plant residues and in the upper soil layer. In the period of full ripeness of pre-crops, before their harvesting, the potential of weed seeds in the 0-5 cm layer after winter rape is 36. 9 % lower than after corn for grain and 44.3 % compared to sunflower. A longer post-harvest period after winter rape helps clear the top layer of the soil from weed seeds to sowing winter wheat by 30.8 %. The lack of a time interval from harvesting of sunflower and corn before sowing of winter wheat leads to the accumulation of weed seeds in the 0-5 cm layer.At this time the culture is marked by negative dynamics of infestation of the top layer. This process takes place more intensively after winter rape and is 47.2 %. With deepening in the soil to 10 cm, the number of weed seeds is reduced. Use of no-tillage technology changes the formation of agrophytocenosis of winter wheat. After the predecessor of winter rape in the tillering phase, the number of weeds is reduced by 34.1 % compared to sunflower and by 47.1 %-to corn. Different efficiency of pre-crops in the reduction of weed populations can be traced in the future during the growing season of winter wheat. In the period ofwinter wheat earing, the contamination of crops is significantly reduced for all pre-crops.But it is not only the result of chemical weeding carried out in the tillering phase, but also real competition of the culture itself, as there is an increase in its vegetative mass. Weeds in this period have a small mass, little different in pre-crops, located in the range from 9.3 to 12.2 g. m-2. To the full ripeness of winter wheat, the contamination of crops increases and this is due to the "clarification" of crops, when the culture no longer competes with weeds. During this period, the pattern established bythe pre-crops in the previous phase remains.

At present, agricultural production of the region faces the main task – to ensure further growth and greater production stability of winter wheat. The new No-till technology for the arid zone of Stavropol Territory is an optimal option within the system of resource-saving technologies. Its application in the peasant farm Vodopyanov S.S. in the conditions of dark chestnut soil became possible with the introduction of a scientifically valid system of farming and sufficient availability of equipment, fertilizers and pesticides at the enterprise. The study of the effect of the No-till technology and precursors on agrophysical and agrochemical properties of dark chestnut soil in the arid zone showed that the winter wheat crops have the largest amount of productive moisture reserve in the upper layer (0.0–0.20 m) during the booting stage of winter wheat for sunflower and winter rape. The largest amount of agronomically valuable aggregates is noted in winter wheat crops in the booting stage for sunflower, and to the blooming stage it increases for all precursors. The soil density of winter wheat crops increases down the layers. The number of water-stable aggregates increases to the firm ripe stage. As nitrogen consumption by plants increases, the amount of nitrate in the soil decreases and reaches its minimum by the firm ripe stage. The maximum concentration of labile phosphorus in the soil is observed during the initial sampling period. Regardless of the precursor, there is a tendency to pH decrease. There is a decrease in humus and mobile sulfur down the soil layers. In general, the No-till technology and precursors affect the reduction of nitrogen, phosphorus and potassium in soil.