Articles
NITROGEN UPTAKE IN A BROCCOLI CROP. 1: NITROGEN DYNAMICS ON A RELATIVE TIME SCALE
Article number
627_25
Pages
195 – 202
Language
English
Abstract
Broccoli has a short growing period and a high demand for nitrogen.
To avoid N leaching from soil and ensure better economy for the grower, it is essential to choose the right time for N application.
We present nitrogen uptake curves for three fertilizer N levels viewed on a relative time scale from planting to harvest, based on six field experiments with broccoli in southern Norway in 1999 and 2001. Total fertilizer N was split in four applications, at planting and 2, 4 and 6 weeks after planting.
Plant N and soil inorganic N (Nmin) were sampled at regular intervals throughout the whole growing period.
At the highest fertilizer N level, 240 kg N ha-1 applied, N did not appear to be limiting nor excessive.
The N uptake at this fertilizer level appears to give a good impression of the nitrogen requirement of broccoli plants through the growing period.
N concentration is compared to the critical %N values from N_ABLE, used for modelling N dynamics in vegetable crops.
The early maturing cv.
Milady F1 did not accumulate N earlier than the main cv.
Marathon F1. Data show that rapid N uptake in broccoli starts about the same time as the small heads just become visible to the eye.
This could be a practical indicator for timing of an additional fertilizer N application.
To avoid N leaching from soil and ensure better economy for the grower, it is essential to choose the right time for N application.
We present nitrogen uptake curves for three fertilizer N levels viewed on a relative time scale from planting to harvest, based on six field experiments with broccoli in southern Norway in 1999 and 2001. Total fertilizer N was split in four applications, at planting and 2, 4 and 6 weeks after planting.
Plant N and soil inorganic N (Nmin) were sampled at regular intervals throughout the whole growing period.
At the highest fertilizer N level, 240 kg N ha-1 applied, N did not appear to be limiting nor excessive.
The N uptake at this fertilizer level appears to give a good impression of the nitrogen requirement of broccoli plants through the growing period.
N concentration is compared to the critical %N values from N_ABLE, used for modelling N dynamics in vegetable crops.
The early maturing cv.
Milady F1 did not accumulate N earlier than the main cv.
Marathon F1. Data show that rapid N uptake in broccoli starts about the same time as the small heads just become visible to the eye.
This could be a practical indicator for timing of an additional fertilizer N application.
Authors
I.M. Vågen
Keywords
Brassica oleracea var. italica, Critical %N, Nmin, Variety, Yield
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