The aim of the research is to reveal the opportunity of applying reduced doses of mineral fertilizers by changing application method and combined usage with phytohormones for potato growing at summer planting time. There were three cultivars under study: Tiras (early), Slavyanka (mid-season) and Zabava (mid-early). Three backgrounds of nutrition were investigated: without fertilizers (control), N90P90K90 broadcast, and N45P45K45 localized in soil layer 0–12 cm; there also were the variants with plant treatment in the phase of budding by phytohormones “Diazofit”, “Adaptofit”, and “Agrostimulin”. It is established that for the conditions of south Ukraine under drip irrigation tuber yield increases by 43–45 % due to applying mineral fertilizers regardless of dose and application method. Doses studied N90P90K90 broadcast and N45P45K45 localized in soil layer 0–12 cm create nutritional regime of soil and crop yield on the same level. In the phase of complete tuber maturity the content of Ð2Î5 was 16.07 mg/100 g in the variant with N90P90K90 (broadcast) and 17.23 mg/100 g in the variant with N45P45K45 (localized); the content of Ê2Î –20.10 è 19.57 mg/100 g respectively. The yield of cultivar Tiras was 23.1 and 23.2 t/ha respectively, Zabava – 25.6–26.7 t/ha, and Slavyanka – per 26.8 t/ha. Phytohormones facilitate potato yield increasing on the background without fertilizers by 4–5 %, and on the fertilized one – by 5–8 %. The quantity of dry matter at applying mineral fertilizers depending on the cultivar increased from 1.6 to 3.2 % in absolute values, ascorbic acid – 0.4 to 1.5 %, and starch – 0.4 to 3.2 %. Phytohormones increased the content of these substances by 0.2–0.3 %, but reduced crop intake of nitrates by 8–14 % in relative values depending on the potato cultivar and phytohormone type.
Keywords: potato, cultivar, mineral fertilizers, localized application, yield, tuber quality, phytohormones.
