Economic and energy efficiency of fertilizers application in potato cultivation in the conditions of the Right-bank Forest steppe of Ukraine

The influence of elements of intensive potato cultivation technology, in particular, on the application of organic-mineral fertilizers in the cultivation of varieties for different types of ripeness and their economic and energy efficiency in the conditions of the Right Bank Forest-steppe of Ukraine, is investigated. It was established that among the studied variants, the maximum efficiency was provided by the planting of medium-ripe varieties under fertilizer application with the normal background (40 t / ha of manure) + N 120 P 120 K 120 . The increase in yields in relation to control in these variants was 2.4-10.0 t / ha in medium-early varieties, 2.1-9.6 t / ha in medium-ripe varieties and 3.2-11.0 t / ha in medium -late varieties. At the same time, the production costs were in the range of 41767.51-50705.22 UAH / ha, 41863.02-50768.89 and 41385.47-50386.85 UAH / ha, respectively. Additional costs included the cost of acquiring and contributing organic and mineral fertilizers, as well as the costs of harvesting, transporting and marketing of the extra crop obtained from the application of fertilizers. The lowest level of production costs was characterized by the variants without fertilizers 35944.25-36772.01 UAH / ha. The cost of production in the period of research largely depended on the level of yield and average selling price. When the fertilizer background (40 t / ha of manure) was introduced, the profit was in medium-early varieties – 66732.49 UAH / ha, medium-ripe varieties 67686.98 and medium- late varieties – 62914.53 UAH / ha. While in control this indicator was at the level of 57155.75-65427.99 UAH / ha. In variants with the introduction of full organic-mineral fertilizers in the soil the most profitable was the variant with the application of (background + N 120 P 120 K 120 ) in medium-early varieties - 84394.78 UAH / ha, medium-ripe varieties 85031.11 and medium-late varieties - 81213.15 UAH / ha. Application of other norms of mineral fertilizers on the background of organic increased the level of the analyzed index in all studied varieties relative to the control variant. The highest efficiency of the applied fertilizer standards was obtained on the variants background (40 t / ha of manure) + N 90 P 90 K 90 , in the cultivation of medium-early and medium-ripe varieties, the cost of 1 t of tubers for these variants amounted to 1312.99 UAH and 1304.99 UAH., the level of profitability was 166.57% and 168.20% respectively. In terms of varieties, the lowest effect was achieved when growing medium-late varieties of potatoes, with the highest profitability in the variant: the background (40 t / ha manure) + N 120 P 120 K 120 - 161.18%. Cost of 1 t of tubers under this variant amounted to 1340.08 UAH. Consequently, the calculations show that the expected positive effect of increasing the dose of mineral fertilizers in the technology of growing potatoes, allows receiving higher yields of tubers, but the economic effect of applying higher doses of mineral fertilizers decreases, primarily due to the high cost of mineral fertilizers, which significantly increased the cost of grown products. After calculating the energy efficiency of the effect of fertilizers on the productivity of different varieties of potato ripeness, it was found that the highest returns were obtained in variants with the application of soil fertilizer background (40 t / ha of manure) + N 60 P 60 K 60 . Where the highest rates of energy efficiency were obtained: for medium-early varieties - 3.04, for medium-ripe varieties - 3.14. Also, high values have become available on the variants with 40 t / ha of manure and background (40 t / ha manure) + N 90 P 90 K 90 in the ground. In particular, when 40 tons / ha of manure were introduced into the ground, potatoes of medium-late varieties were planted with the highest coefficient of energy efficiency of 2.85. Consequently, an increase in the norms of mineral fertilizers for potatoes from (N 60 P 60 K 60 ) to (N 120 P 120 K 120 ) contributed to the increase in yields, but at the same time the agronomic and energy efficiency of fertilizers decreased significantly, which contradicted the principles of intensification of agricultural production. In general, the energy efficiency of mineral fertilizers transferred directly to potatoes is rather high, since the energy efficiency factor significantly exceeds the unit, which indicates the energy saving of the investigated technology of potato cultivation. It is expedient to apply fertilizer rates to those in which it is possible to obtain the greatest energy efficiency at the optimal cost, ensuring compliance with the priority energy saving policy in agrarian production. Key words: potato, variety, fertilizer, yield, prime cost, profitability level