The aim of the investigations consisted in determination of the optimum ratio of structural components in the sowing layer of the chernozem on cultivation of cereal ear crops and development of a combined tillage machine performing the sought for optimization. The method of simplex-lattice planning of experiments has been chosen for establishing the optimum ratio. The investigations have been carried out with structural components in the size from 20 to 5 mm (XI), 5-2 mm(X2). 2-0.25 mm (X3) and less than 0.25 mm (X4).The optimum ratio of structures depends mainly on the level of moistening, mineral nutrition and seed size of crops sown. At favorable conditions crumbles XI, dominate in the optimum texture under the lack of moisture the share of X2 and particularly X3 ( X2+X3 attain 80 %) abruptly increases. The ecological value of agronomically most valuable size (5-0.25 mm) consists first of all in the provision of more effective use by field crops of the available soil moisture and in the reduction of the negative effect of drought. A construction of combined (tillage and sowing) machine has been developed for realization of mentioned agronomical demands. This machine has been subjected to the full cycle of successful agronomical and energetic tests.