Impact of nitrogen fertilization on raspberry (Rubus idaeus L.) fruit quality and soil fertility

This study investigates the effects of nitrogen fertilization on raspberry fruit quality and soil fertility over two years. The experiment involved the application of complex NPK fertilizers and varying doses of nitrogen fertilizer (CAN) to raspberry plants of ‘Willamette’ and ‘Tulameen’ cultivars in the Ivanjica raspberry region. Results indicate a positive correlation between nitrogen doses and soil fertility, with ‘Tulameen’ soil showing lower nutrient levels compared to ‘Willamette’. Increasing nitrogen doses led to higher levels of primary and secondary chemical compounds in raspberry fruit, particularly in the ‘Willamette’ cultivar. Physical fruit properties were influenced by both variety and nitrogen doses, with significant effects observed in the first year of the study. Proper fertilizer application is crucial for achieving high and stable raspberry yields and fruit quality, while excessive nutrient application may lead to environmental pollution. Based on the comparison of soil fertility parameters and raspberry fruit quality, the recommended fertilizer dosage for raspberry cultivation in the Ivanjica raspberry region is 500 kg ha-1 of NPK fertilizer (16:16:16) and 300 kg ha-1 of CAN.