S13 - Session P3 - Nitrogen effectiveness on blueberry yield and quality

Authors: Jana Apse *, Aldis Karklins, Anita Osvalde

Research on mineral nutrition for high-bush blueberries in Latvia is at a very early stage. Our studies was devoted to nitrogen n plant nutrient with high mobility and significant impact on vegetative growth and yield formation. The field experiment was carried out in plantation established 3 years ago. Experimental plots with blueberry cultivar 'Chippewa' were arranged on gently slope with mineral soil developed from moraine. Original topsoil's reaction was pH KCl n 6.41, organic matter content 20 g kg -1 . Before planting strips under bushes was conditioned using acid sphagnum peat. Five experimental plots each of them consisting from 8 bushes was set up. The objective of research was to determinate the effect of different fertilizer treatments (0; 40; 80; 120 and 160 kg ha-1 N) on biochemical contents in the berries and the yield, as well as on the chemical composition of leaves. Soil reaction was determined potentiometrically, organic matter in mineral soil according to the Tyurin's method, in organic materials n by dry combustion, total nitrogen using Kjeldahl method. Samples of leaves were taken during the vegetation for NPK and Mn, B and Mo analysis. Research showed that different nitrogen fertiliser rates did not significantly influenced blueberry yield, but changed biochemical composition of berries. In second year, the highest phenol content in berries was around 80 kg N ha-1, while both the first and the third year results show a different picture. The highest content of anthocyanin in blueberries was N 0 and N 160. This could be due plant's response to stress, resulting in plants enhanced formation of secondary metabolites.