THE EFFECTIVENESS OF THE USE DIFFERENT FERTILIZER SYSTEMS UNDER THE CONDITIONS OF RAIN-FED AND IRRIGATED AGRICULTURE FOR CROPPING ROTATION IN THE STEPPE ZONE OF THE CENTRAL CAUCASIAN REGION
Introduction. The article presents the results of research for the 7th rotation of crop rotation (2010-2019) in a long stationary experiment in 1948. According to the assessment of the use of different fertilizer systems, the soil of the experimental site is ordinary carbonate heavy loamy chernozem, the parent rock is micellar-carbonate loess-like loam of predominantly Aeolian origin. Object. The object of the study were: winter soft wheat, corn, sunflower and alfalfa. The purpose of the research is to determine the effect of recommended and calculated mineral and organo-mineral fertilizers on the yield of winter wheat, corn, sunflower, alfalfa in the grain-grass crop rotation and the productivity of a hectare of ordinary carbonate chernozem arable land in rain-fed and irrigated conditions under various mineralogical indicators of the growing seasons, based on monitoring of the corresponding indicators for the period of 7 rotation in the crop rotation. Materials and methods. The experience is laid down in the form of a 10-full crop rotation on rain-fed and irrigated conditions, in a twofold repetition. Alternation of crops: alfalfa for hay 1 and 2 years of use, winter wheat, corn, corn, sunflower, winter wheat, corn, corn, winter wheat. Results and conclusion. Studies have found that the systematic use of different fertilizer systems has increased the yield of crop rotation crops. On average, during the rotation, the effect of using the recommended mineral fertilizer system (in the form of an increase in yield) for all crops, on rain and irrigation, respectively, was: 40-90 % and 59-93 %; the recommended organo-mineral system - 57-110 % and 89-116 %. The use of the calculated mineral fertilizer system in irrigated conditions provided an increase in crop yields by 70-103%, the calculated organo-mineral - 110-132%. Crop rotation productivity was also higher when using the recommended and calculated organo-mineral fertilizer systems for irrigation, respectively, 60.4 and 66.6 c.z. units/ha. The data obtained can be used to develop a model for the use of mineral and organic fertilizers and forecast crop yields.