NITROGEN OPTIMIZATION FOR BLUEBERRY CULTIVATION

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-14-8 / ISSN 1314-2704, June 19-25, 2014, Book 3, Vol. 2, 199-206 pp

ABSTRACT
Highbush blueberries (Vaccinium corymbosum L.) are becoming more and more popular in Latvia and area of commercial plantations is increasing annually accounting 220 hectares in 2012. One of the points of interest is balanced fertilisation to match the crops’ need for development of good stand, as well as to secure the high yield potential with relevant quality characteristics and storage properties. Similar to other horticultural crops, nitrogen management is quite complicated due to it mobility, transformations, effect on plant winter resistance, vegetative growth, berry storage properties, taste etc. As blueberries prefer the acid growth medium, some differences might be relevant for choise of nitrogen form – ammonium or nitrate. The nitrogen management for blueberries was chosen as a main topic for experiment set up in Varmiera district in 2012 where plantation was established 4 years ago. Experimental plots with blueberry cultivar ‘Chippewa’ were arranged on gently slope. Original topsoil’s reaction was pH KCl – 6.26, organic matter content 30 g kg-1. Five experimental plots each of them consisting from 8 bushes was set up. Soil reaction was determined potentiometrically, organic matter in mineral soil according to the Tyurin’s method, in organic materials – by dry combustion, total nitrogen using Kjeldahl method, but mineral nitrogen (N–NO3 and N–NH4) – spectrophotometrically. Samples of leaves from each experimental plot were taken during the vegetation for NPK nutrition diagnosis. Research showed that nitrogen fertiliser applications significantly affected ammonium and nitrate ion concentration in soil (0 – 60 cm). Sphagnum peat (pH KCl 3.0) as a soil modifier allowed efficiently reduce the soil reaction at the root zone and provided an optimal environment for blueberries as well as increased organic matter content in the soil. Interactions of nitrogen applications and peat mineralization also was studied as well as nitrogen immobilization in the root zone

Keywords: fertilisation, nitrogen forms, blueberry cultivation, soil properties.