Nitrogen fertilizer effect on cranberry fruit yield and quality

Nitrogen (N) is the most important element that influences both vegetative growth and fruiting in cranberry production.
While many factors such as cultivar, age and vigor of vines are important, soil fertility is one of the most important factors impacting yield and fruit quality.
Cranberry fruit yield can increase with additional fertilizer N; however, N application can also lead to increased fruit rot and excessive vegetative (stolon) growth on the plant, thus creating a dense canopy with high relative humidity (RH) microclimate.
Wet and humid conditions encourage the expression of cranberry fruit rot.
Our goal was to determine the effect of fertilizer N application rate on cranberry fruit rot and quality in cranberry cultivars ‘Stevens’ and ‘Mullica Queen’. Biophysical data were collected by deploying microclimatic sensors in each treatment.
Four N rates were used ranging from 45 to 112 kg N ha^‑1 in a designed factorial experiment.
Cranberry biomass in both cultivars increased with an increase in N rate and so did fruit rot.
Fruit yield increased with N rate up to 90 kg N ha^‑1 in ‘Mullica Queen’ and up to 67 kg N ha^‑1 in ‘Stevens’, then declined.
High N rate of 112 kg N ha^‑1 was associated with a high RH compared to 46 kg N ha^‑1 in both cultivars.
Total anthocyanins decreased with N rate while titratable acids increased with N rate.
Fruit rot exceeded 25% in ‘Stevens’ at 112 kg N ha^-1, compared to 12% in ‘Mullica Queen’. Our results suggest that high N rate encourages fruit rot expression.

IV International Symposium on Beverage Crops

P. Jeranyama, B. Makeredza, G. Mupambi

cultivar, fruit rot, anthocyanins, titratable acid, relative humidity, temperature

https://doi.org/10.17660/ActaHortic.2026.1466.44