Soil applied nitrogen and foliar fertilizers together with biostimulators increase productivity but decrease antioxidative potential in hazelnut
A combination of soil applied nitrogen (N) together with foliar applied macro- and micro-nutrients and biostimulators were used in a production orchard of 'Istrska dolgoplodna leska' during two consecutive years in order to improve quantity and quality of the yield. Calcium ammonium nitrate (KAN) and calcium cyanamide (CC) were applied three times and once, respectively during spring time. Foliar program (FP) included both aminoacids and nutrients, such as Fe, Zn, B, Co, Cu, Mn, Mb, P, K, S and N within products Delfan plus, Tradecorp AZ plus, Calitech, Trafos K, Folur and Tytanit. Nutritional sprays were combined with bacterial blight and hazelnut weevil control, performed from leafing-out to postharvest period. Four treatments i.e., KAN, CC, KAN-FP and CC-FP were compared with untreated control (C). In two-year average, the KAN-FP combination caused an increase of the yields from 8.2 (CC-FP) up to 34% (C). The same treatment resulted in the highest kernel percentage, but the lowest percentage of marketable kernels. When only KAN was soil applied, the heaviest in-shell and kernel weight, as well as the highest increase of number of the nuts per fruiting in one-year-old shoot (nuts shoot-1) were observed. The applied CC resulted in an increased shoot length and basal diameter, as well as the nuts shoot-1, compared to CC-FP combination, where the increased number of the nuts shoot-1 was observed on shorter and thinner fruiting shoots. Neither N alone nor N together with foliar fertilizers led to higher nutraceutical value of the kernels, measured as the total phenolic content and antioxidative potential.
Solar, A., Jakopic, J., Stampar, F. and Veberic, R. (2018). Soil applied nitrogen and foliar fertilizers together with biostimulators increase productivity but decrease antioxidative potential in hazelnut. Acta Hortic. 1226, 281-288
Corylus avellana L., fertilization, yield, nut and kernel quality, shoot growth