Nitrogen accumulation in the bulbs and tops of
intermediate day (open squares) and long-day
(diamonds) varieties of fresh market onions grown in
the high desert near Lancaster, CA. Yields were
approximately 828 and 700 cwt/acre, respectively.
Uptake was very slow for the first half of the
season, until the early bulbing stage. Uptake was
steady during bulb development until early maturity,
at about 3.1 lbs N/acre/day for the intermediate
variety and 1.7 lbs N/acre/day for the long-day
variety [2].
Nitrogen distribution in fresh market onions
grown near Lancaster, CA. Values represent the
means of two intermediate-day varieties and one
long-day variety [1].
Nitrogen removed at harvest with onion bulbs. The overall average is weighted for the number of observations in each trial. More information can be found here [3].
The amount of N removed per unit of yield is higher for onion varieties with a high percentage of dry matter. However, because yields are higher for onions with less dry matter, total N removal may not differ.