Articles
EFFECT OF N-SUPPLY ON GROWTH AND YIELD OF BROCCOLI MEASURED NON-DESTRUCTIVELY BY GAMMA-SCANNING
Different N-levels were established by fertilization with 0, 50 and 100 kg/ha N prior to planting.
During growth, all treatments were fertilized equally in 10 day intervals with 6 top dressings.
The quantities of the top dressings (5, 15, 50, 60, 90, 80 kg/ha N) reflect the average N-uptake of broccoli.
The fresh matter growth was non-destructively measured by a gamma-scanning-technique in 1–3 day intervals until harvest.
During the first 3 weeks, the treatments showed no significant differences in fresh matter growth.
After 3 weeks, crop growth with an N-buffer of 0 kg/ha N was lower compared to the other plots.
Destructive measurements at harvest showed a significant difference in the total mass (range 95–100 t/ha fresh matter) with N-buffers of 50 and 100 kg/ha N compared to an N-buffer of 0 kg/ha N (81 t/ha fresh matter). Treatments did not affect marketable yield which ranged from 22 to 24 t/ha.
The results show that it is possible to obtain a high yield of broccoli with a small N-buffer at planting and frequent top dressings according to the N-uptake of the plants.
With this procedure, the risk of leaching on sandy soils can be reduced.