THE INFLUENCE OF MINERAL FERTILIZERS ON THE CONTENT OF SOLUBLE SOLIDS AND ASCORBIC ACID IN FRUIT OF THE VENIAMINOVSKOYE APPLE VARIETY

Abstract

The results of the study of the effect of different doses of nitrogen and potash fertilizers applied to the soil and used as foliar feeding on the content of soluble solids and ascorbic acid in fruits of the scab-immune apple variety Venyaminovskoe are presented. The experimental orchard was planted in 2013. The planting density of trees is 6 × 3 m. Annual fertilization in the field experiment was applied since 2015. The experience is based on the application of increasing doses of nitrogen and potash fertilizers in combination with foliar fertilization with these elements and without them. As a result of the conducted research (2017–2019), it was found that the most significant factor affecting the content of soluble solids and ascorbic acid is the weather conditions of the growing season: a significant increase in soluble solids and a decrease in the concentration of ascorbic acid in a year with an optimal temperature and humidity regime during the fruit ripening period in August was revealed. The accumulation of ascorbic acid in fruits was favourably affected by the weather conditions of 2017, when there was an excess of precipitation in August. Significantly higher (30–80% higher than the control without fertilization) content of ascorbic acid in apples contributed to the introduction of nitrogen fertilizers in the soil at a dose of N 90 K 120 for three years. Soil and foliar application of nitrogen and potash fertilizers did not have a significant impact on the content of soluble solids in fruits of Venyaminovskoe apple variety.