Bordiuzha I. Optimization of Mineral Nutrition of Potato for Growing on Dark Gray Opodzolic Soil in the Left-Bank Forest-Steppe of Ukraine

The dissertation is devoted to the theoretical and practical argumentation for development of the agrochemical and economic effective scheme of the fertilization for potato plants in it growing on dark gray opodzolic soil. This scheme optimizes plant nutrition and combines using of the solid mineral fertilizers (nitrogen and potash fertilizers) and liquid fertilizers (phosphorus fertilizers) with methods for stimulation of the tuber’s growth (tuber treatment) and stimulation of the plant growth (foliar application). The practical value of the results in investigation was to supplement the modern notions of changes in the agrochemical characteristics of dark gray podzolized soils for the use of liquid forms of phosphate fertilizers, which are determined positive trends regarding the conditions of nutrition of potato plant dishes. Application of phosphate fertilizers affects the nutritional status of the abovementioned soil positively. Inclusion in the fertilizer scheme instead of mono ammonium phosphate of liquid phosphate fertilizers APP 11–37 in the rate P105 on the background of nitrogenpotassium (N120K180) provided the average degree of supply by mineral nitrogen compounds in the arable layer (15.7–25.2 mg/kg of soil). Very high degree in relation to mobile compounds of phosphorus (227–277 mg/kg of soil) and potassium (175–258 mg/kg) were determined during the critical period of growth and development of potato plants (budding – «green berry»). The application of liquid phosphorus fertilizers resulted in high intensity of the physiological and biochemical processes in potato plants into the flowering phase: the net productivity of photosynthesis reached a limit of 12.1–14.5 g/m2×day, and the leaf index was 5.46–6.26. The fertilizer scheme, which was based on replacing with liquid complex fertilizer APP 11–37 (P105), determined the optimum level of accumulation in nitrogen (3.11–4.00 %) of the plants in the critical period (budding-flowering), phosphorus (0.61–0.94 %) and potassium (4.34–6.75 % on dry matter). The using in the scheme of potato fertilization instead of amphosus liquid phosphorus fertilizers APP 11–37 in the rate P105, pre-planting treatment of tubers in a 0.20 % solution of Atonik Plus by the applicator on the inspection table and two times foliar spraying of the plants by this preparation (2×0.6 l/ha) caused tuber yield at 52.2 t/ha. The increase to the ammophos variant (Р105) amounted to 14.4 t/ha. Reducing the rate P from 105 to 70 kg/ha of the application of liquid phosphorus fertilizers APP 11–37 caused a decrease in the yield increase by 3.10 tons/ha, and up to 35 kg/ha – by 8.70 tons/ha compared to the maximum phosphorus norm (P105). Replacement of solid fertilizers (ammophos) with liquid phosphorus (APP 11–37) has led to an increase in the costs of potato growing. However, at the expense of higher yields for this technological reception, the cost of potato system production was increased to 70 thousand UAH compared with those where the traditional form (ammophos) was used. And the level of profitability was increased up to 75.1 %. Reducing the rate of these fertilizers to P70 caused a decrease in the cost of potato production to the level of 62.2 thousand UAH. and Р35 – to 42.0 thousand UAH.