Optimum leaf nutrient concentrations of wild lowbush blueberry in Quebec

Abstract

To evaluate the nutritional status of wild lowbush blueberry (Vaccinium angustifolium Ait.), optimum leaf nutrient concentrations were developed in earlier studies conducted in Canada's Maritime Provinces and in Maine. However, these concentrations have not been validated under the climatic and edaphic conditions of the Saguenay-Lac-Saint-Jean region of Quebec (Canada). These concentrations may not be necessarily correlated with the high productivity levels recorded in this region in recent years. The objective of the study was therefore to determine the minimum and maximum blueberry leaf nutrient concentrations under the conditions characterizing this region. These concentrations were derived using the boundary-line approach, which involves estimating the relationship between maximum fruit yield and leaf concentrations of N, P, K, Ca and Mg. The data were obtained from N and P fertilization trials carried out between 2001 and 2006 in eight blueberry fields in the Saguenay-Lac-Saint-Jean region. On average, more than 80% of the samples analyzed met the minimum leaf nutrient concentrations. Minimum leaf N and Mg concentrations were comparable to those obtained in earlier studies. Minimum leaf concentrations were revised downward for P and Ca. Only minimum K concentration was higher compared with published standards. Maximum leaf concentrations were revised downward for all nutrients. Minimum and maximum concentrations were 16.36–20.55, 1.19–1.66, 5.40–7.10, 2.93–3.88 and 1.34–1.81 mg g-1 for N, P, K, Ca and Mg respectively. These concentrations were used to establish sufficiency ranges suited to wild lowbush blueberry growing conditions in the Saguenay-Lac-Saint-Jean region. Key words: Vaccinium augustifolium Ait., nutritional standards, yield-nutrients relationship