Seasonal pattern of the N content of 'Thompson Seedless'
grapevines in Fresno County with a yield of 12.5 tons/acre
[15].
N uptake is generally relatively low between budbreak and
bloom but high between bloom and veraison. [8,15].
In 5-year old 'Thompson Seedless' grapevines with a yield of
12.5 tons/acre, about 30% of the total N was found in the
clusters. N is also removed with canes when the vines are
pruned [15].
Nitrogen removed with harvested clusters (wine grapes and raisins). The overall average is weighted for the number of observations in each trial. More information can be found here [5].
Wine grapes
Raisins
Values for table grapes can be derived from the values for raisins by adjusting for the higher moisture content at harvest (on average 80.9%). Using this adjustment, the N removed per ton of harvested table grapes averages 2.26 lbs N/ton, ranging between 1.78-2.81 lbs N/ton [5].