The influence of humus extract on the quality of raspberry (Rubus idaeus L.)

This paper analyzes the influence of foliar fertilizer based on humus extract on some of the elements central to the quality of the Polka raspberry variety in the area of the city of Bihać. The research was conducted in 2015 according to the control and treatment system. A foliar fertilizer based on humus extract was used for the treatment. A total of 12 quantitative and qualitative properties were analyzed: content of total sugars, reducing sugars, invert sugars, sucrose, water content, dry matter, total acidity, vitamin C, total phenols, total flavonoids, antioxidant capacity, and fruit mass. After the analyses were completed, it can be concluded that fruits of raspberry plants treated with humus extract have an almost identical value of total acidity (1.65%) as found in control. However, treatment with a humus extract slightly lowered the content of total phenols and vitamin C. Based on the results obtained, it was shown that the foliar fertilizer based on the humus extract did not have a positive effect on certain chemical and antioxidant properties of the raspberry fruit.