ARS | Publication request: Nitrogen fertilizer practices for rapid establishment of highbush blueberry: a review of 6 years of research

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2012
Publication Date: June 17, 2012
Citation: Bryla, D.R., Vargus, O. 2012. Nitrogen fertilizer practices for rapid establishment of highbush blueberry: a review of 6 years of research. Meeting Abstract. Meeting booklet.

Technical Abstract: Three field trials were conducted in Oregon, USA, from 2006 to 2011 to evaluate nitrogen (N) fertilizer practices for establishment of highbush blueberry. In the first trial, we compared the effects of N fertigation (injection of fertilizer through a drip system) to conventional granular fertilizer application in 'Bluecrop' blueberry and found that fertigation produced more growth and less salt injury in young plants than granular fertilizers, but fertigation required >150 kg/ha N to reach maximum plant growth potential during the first 2 years after planting. More N was needed by fertigation because ammonium-N, the preferred form of N by blueberry, is immobile in soil. Unlike granular fertilizer, which was applied by hand around the base of the plants, much of the injected fertilizer wound up between the young plants and therefore was unavailable for plant uptake. In the second trial, we examined the effects of fertigation using three different methods of water placement in six cultivars of blueberry and found that two laterals of drip, which is now a common practice in blueberry, was worse in each cultivar than a single line. Drip emitters with two lines placed the ammonium fertilizer too far from the roots of the young plants and resulted in low leaf tissue N levels. The third and most recent trial was planted with 'Draper'. The objective of this study was to identify fertilizer practices that increase N uptake and plant productivity during establishment, including humic acids, controlled-release fertilizers, and small but safe application of granular fertilizer shortly after planting. After 1 year, we found once again that drip placement was important, where fertigation with one or two laterals located near the base of the plants produced more growth than two laterals located 0.2 m from each side of the plants, even when granular or slow-release fertilizer was applied in early spring prior to fertigation. Fertigation with humic acid fertilizer or urea sulfuric acid also produced better growth than liquid urea commonly used in blueberry.