The exploratory research results on the development of a system for the application of mineral fertilizers in perennial plantings in the foothill zone of the Kabardino-Balkarian Republic

The objects of the research are the following: Florina apple tree variety on semi-dwarf rootstock SK-2, immune to scab, according to the planting scheme of 2x5 m; young intensive orchard of promising apple varieties on dwarf rootstock M-9 according to the planting scheme of 3.5x0.8 m. The objective of the research is to develop an effective system of application of mineral fertilizers, timed to the main phases of plant development in intensive apple tree plantations in the foothill zone of the Kabardino-Balkarian Republic. For this purpose, the problems of determining the effect of foliar feeding on the growth, development, productivity and quality of apple fruit production against the background of mineral fertilizers, adjustment of rates, doses, timing and methods of their application have been solved. The research methods used are analytical, statistical, field ones. Field and laboratory experiments were carried out in accordance with the guidelines for laying out and conducting experiments with fertilizers in fruit and berry plantations [6], and the methods of field experiment of B.A. Dospekhov [3]. The Results of the research and their novelty. The best results in terms of productivity and crop quality were obtained with the variant “Nitroammophoska” (16-16-16) 120 kg active ingredient/ha + calcium nitrate 25 kg active ingredient/ha + foliar feeding". With this variant, the Florina apple variety gave a 5% yield excess over the control variant. The dry matter content and the amount of sugars corresponded to the optimal content in apple fruits. The vitamin C content fluctuated within 7.5-12.32%, the maximum value of this indicator was obtained with the control variant. The acidity percentage was lower with the variants “Nitroammophoska” (16-16-16) 90 kg active ingredient/ha and "Nitroammophoska (16-16-16) 120 kg active ingredient/ha" and is 0.33 mg/%. In all variants with the use of fertilizers in the fruits of the Florina variety, except for the variant “Nitroammophoska” (16-16-16) 60 kg active ingredient / ha + calcium nitrate (25 units), an increase in the sugar-acid index by 6-8 units was observed compared to the control (26 units), which showed an improvement in the taste of fruit products in these variants.