Fertilization and nutrient physiology of small fruit crops

Authors: Bryla, David

Submitted to: Acta horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 3/15/2025
Publication Date: 6/27/2025
Citation: Bryla, D.R. 2025. Fertilization and nutrient physiology of small fruit crops. Acta horticulturae. 1432:1-14. https://doi.org/10.17660/ActaHortic.2025.1432.1.
DOI: https://doi.org/10.17660/ActaHortic.2025.1432.1

Interpretive Summary: Small fruit crops, such as blueberries, blackberries, and raspberries, thrive in fertile, well-drained soil, but will give good returns almost anywhere when managed properly and provided with adequate fertilizers. An ARS scientist in Corvallis, Oregon conducted years of research on fertilization of each of these crops to provide insight into how production is affected by application methods and deficiency or excess of commonly applied nutrients. The studies were largely conducted in northwestern United States, where the fields are often fertilized with nitrogen, phosphorus, potassium, calcium, and boron. The findings indicated that fertigation or injecting a liquid source of nitrogen fertilizer through the drip irrigation system resulted in more growth and fruit production than granular applications of nitrogen fertilizer in blueberries. Other nutrients can also be applied by fertigation in blueberries but are only needed when leaf concentrations are below the recommended range. Source or method of fertilizer application appears to be less important in blackberries and raspberries, because the plants are very efficient at reallocating nutrients from older canes and roots.

Technical Abstract: Global production of small fruits, such as blueberries, blackberries, and raspberries, is on the rise. This review summarizes recent research on fertilization of each of these important crops and provides insight into how fruit quality is affected by deficiency or excess of commonly applied nutrients. Until recently, most commercial blueberry fields were fertilized using granular fertilizers. However, many new fields are irrigated by drip and fertigated using liquid fertilizers. Fertigation with N is less efficient initially, but it results in less salt damage and promotes more growth and higher yields than granular fertilizer when optimal rates of N are applied. Other nutrients, including P, K, Ca, and B, can also be applied by fertigation but should only be used when leaf concentrations are below the range recommended for blueberry. Excess K, for example, causes salt damage to the leaves and results in deficiencies of other nutrients, including Ca and Mg. In blackberries and raspberries, which are perennial plants with biennial shoots, nutrient uptake begins very early in the season in second year fruiting canes called floricanes and continues a few weeks later in new canes called primocanes. Therefore, N and other nutrients are usually applied by fertigation or by split applications of granular fertilizer, with the first half applied about a week before the primocanes emerge and the second half applied about a month before the beginning of fruit harvest. Because the plants are very efficient at reallocating nutrients, source and method of fertilizer application appears to be less important in blackberries and raspberries as it is blueberries.