The article deals with the data of the field study in the effect of different doses of mineral fertilizers at the irrigation of ordinary chernozems in the Rostov region. It is established that irrigation is the main factor for obtaining high crop yields (about 14 t/ha) because the plants increase their biometric indices, either the height of plants by 29.1%, or biomass at the end of vegetation by 81.4 %. The greatest increase of the yield 18.6 kg per 1 kg of the active compound of fertilizers was at the variant with the dose of 436 kg (N140Ð60Ê61), the decline of the fertilizer dose to 261 kg (N140Ð60Ê61) or increasing up to 611 kg (N328Ð140Ê143) lead to the lessening of the increase of the yield per 1 kg of the active compound of fertilizer to 10.0 and 15.7 kg respectively. Data analysis of the water consumption shows that it increases at the increasing of the applied dose of fertilizers from 6036 m³/ha at the variant without fertilizing to 6511 m³/ha at the application of N328Ð140Ê143, however due to the yield increasing, the coefficient of water consumption decreased from 1193 to 444 m³/t. The calculation of economic efficiency revealed that profitability of sorghum growing was by 236 and 238 % higher at applying fertilizer dose rated for the planed yield of 10-12 t/ha.
