Nitrogen Form and Solution pH Influence Growth and Nutrition of Two Vaccinium Clones

Summary

This greenhouse hydroponic study examined how nitrogen form (nitrate, ammonium, or mixed) and solution pH (4.5 or 6.5) affected growth and nutrient uptake in two Vaccinium species. Blueberry (Northblue) grew best at pH 4.5 regardless of nitrogen form, whilst cranberry (Searles) responded better to ammonium or mixed nitrogen than nitrate alone at both pH levels. The differential nitrogen preferences were attributed to the native soil conditions where each cultivar was selected—blueberry from nitrate-rich soils and cranberry from ammonium-rich bog soils.

Regional applicability

This fundamental research on Vaccinium mineral nutrition is internationally applicable to blueberry and cranberry production systems. UK commercial blueberry and cranberry cultivation would benefit from pH and nitrogen form optimisation informed by these findings, particularly for containerised production or soil amendment strategies.

Key measures

Shoot growth, fresh weight, final dry weight, tissue nitrogen concentration, root and shoot iron concentration, root and shoot manganese concentration, X-ray microanalysis of root iron precipitation

Outcomes reported

The study measured shoot growth, fresh and dry weight, tissue nitrogen accumulation, and root and shoot concentrations of iron and manganese in two Vaccinium species grown under different nitrogen forms and pH conditions. Species-specific responses to nitrogen form were documented, with blueberry preferring nitrate at acidic pH and cranberry preferring ammonium or mixed nitrogen at both pH levels.

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