Effect of foliar fertilization of microelements on highbush blueberry (Vaccinium corumbosum L.) nutrient status and yield components in cutover peatlands

The commercial cultivation of highbush blueberry in Latvia was successfully started during the last 20 years. In 2018, there was an estimated 280 ha of highbush blueberries planted in Latvia with increasing annual hectarage. In general, blueberry is a highly specialized crop that has definite soil agrochemical and climatic requirements: it has low nutrient needs and is sensitive to excessive nutrient levels in the soil. However, balanced and precise mineral nutrition is essential for producing high and quality yield. The study was conducted in the producing planting of highbush blueberry, cultivar ‘Patriot’, during the vegetation season of 2018. The research was carried out to determine the effect of foliar fertilization with micronutrients (Fe, Zn, Cu, Mo, B) on the productivity, the content of mineral elements in leaves and photosynthesis of blueberries. Field experiment design included foliar fertilizer treatments 0 to 3 times per season. In general, our results revealed that foliar sprays with micronutrients had a positive effect on the berry yield, parameters of photosynthesis and microelement content in leaves of highbush blueberry. It was determined that the application of the foliar fertilizer 4 times per season provided the highest berry yield (134% compared to control) and the highest photosynthetic activity of plants. Our study suggests that correct foliar fertilization can optimize the content of Fe, Zn and B in blueberry leaves.