The research results of deep subsoiling by the improved subsoiler of the mounted chisel type ÃÍ×-0,6Ó under soil and climatic conditions of the Rostov region on the ordinary Ciscaucasia chernozem and dark chestnut soils are cited in the paper. The efficiency assessment of the deep subsoiling was made in comparison with the plowing to the depth of 20-25 cm. The studied crops were winter wheat and stubbly buckwheat. The total water consumption of the winter wheat consists of productive soil moisture resources (3-4 %), rainfall of the vegetation period (61-62 %) and irrigation water (35 %). Those parameters of the buckwheat were 2-3, 24-25 and 73 % respectively. The study of the soil moisture resources under the deep subsoiling in comparison with the deep plowing have shown the increasing use of the productive soil moisture resources for winter wheat from 161 to 234 m³/ha and for stubbly buckwheat from 65 to 110 m³/ha. At the treatments with the deep subsoiling more efficient use of moisture for 1 ton of crop production was observed. The water consumption rate for winter wheat under the deep subsoiling was 853 m³/t, under plowing – 1087 m³/t; for buckwheat – 1832 m³/t and 2486 m³/t respectively. The deep subsoiling with ÃÍ×-0,6Ó provided the optimal conditions for growth, development and productivity increasing of winter wheat from 3.98 to 5.01 t/ha and of buckwheat – from 1.1 to 1.5 t/ha in comparison with the yield under the deep plowing. The calculation of the economic indices was based on the crop yield, gross production value, irrigation water volume, labor inputs and production costs. The profit of crop growing under the deep subsoiling to the depth of 0.6 m using the chisel subsoiler ÃÍ×-0,6Ó was higher 1.3-1.9 times than under the plowing to the depth of 20-25 cm. Additional income was 1.56 thousand rubles per ha for wheat and 0.8 thousand rubles per ha for buckwheat.
