Vegetative and Physiological Responses of “Emerald” Blueberry to Ammoniacal Sources with a Nitrification Inhibitor

Abstract

The nitrogen nutrition in blueberry has been studied by some authors; however, the effect of N-nitrate or N-ammoniacal fertilizers with nitrification inhibitors on plant growth and physiology has not been known. The aim of this investigation was to study the effectiveness and physiological implications of ammoniacal fertilizers, with or without nitrification inhibitors in blueberry. An experiment was conducted on 1-year “Emerald” blueberries grown in 20-L plastic pots. Our data indicate that ammonium-containing fertilizers promote vegetative growth and increase the leaf nitrogen concentration and gas exchange in plants, possibly due to higher nitrogen root absorption compared with nitrate. On the other hand, fertilization with ammonium with a nitrification inhibitor increases the leaf chlorophyll concentration compared with the addition of ammonium without a nitrification inhibitor and nitrate. However, the ammonium supply decreases the concentration of calcium and potassium in leaves. Our data suggest, for the first time, that fertilization with ammonium accompanied by a nitrification inhibitor is an effective strategy to improve the nitrogen status and promote plant development in “Emerald” blueberry.