EFFICIENCY OF FERTILIZER APPLICATION IN GROUPS OF AGRICULTURAL CROPS DEPENDING ON THE LEVEL OF WATER REGIME IN THE ROSTOV REGION

Purpose: to determine the efficiency of mineral fertilizers and the agricultural crops response degree for the main groups (cereals, fodder, legumes and industrial crops, potatoes and vegetables) during irrigation in the aspect of resource saving. Materials and methods: the research was carried out in the Central irrigated zone of Rostov region (FSUE “Semikarakorskoe”). The object of research is different groups of agricultural crops, their reaction to the nutrient status at different levels of moisture supply. The soils of the experimental site are represented by ordinary chernozems. Field observations, research and data processing were carried out according to generally accepted methods: B. A. Dospekhov, A. N. Kostyakov, M. M. Goryanskiy. Results: as a result of the research, it was revealed that regardless the fertilizer status, the calculated water regime contributes to the agricultural crops yield increase by an average of 1.6–3.2 times in comparison with dry conditions. The calculated soil water regime contributed to a significant increase in the efficiency of fertilizers relative to rainfed growing conditions. Under different mineral fertilizers backgrounds, the maximum effect from their use increased: in the group of grain crops (spring barley) by 3.09 times, fodder (alfalfa of previous years) by 2.93 times, legumes (peas) by 2.86 times and potatoes by 4.25 times. Conclusions: the greatest effect from the fertilizers application under irrigation conditions was shown by potatoes, vegetables and grain crops. The highest return on fertilizers by an increase in yield was noted in the cultivation of alfalfa (12.67–13.83 kg) and Sudanese grass (22.00–23.44 kg), as well as potatoes (26.37–24.22 kg) and vegetable crops (22.6–33.4 kg). A severe water regime with a slight decrease in the yield of agricultural crops contributes to the irrigation water saving up to 1050–1580 m3/ha, which is very urgent under conditions of water scarcity.