Early supplies of available nitrogen to the seed-row of a canola crop as affected by fertilizer placement
Thavarajah, D., J.J. Schoenau, J.R. Bettany, G. Hultgreen, P. Qian, S.S. Mahli and R. Lemke. 2003. J. Plant Nutr. 26: 683-690
Abstract
A field experiment was conducted at Star City (legal location
SW6-45-16-W2) Saskatchewan, Canada from May 2000 to June 2000, to measure nitrogen (N) and phosphorus (P) supply rates from fertilizer bands to the seed-row of a canola crop. Ion exchange resin membrane
probes (PRS™) were used to measure N and P supply rates in four
treatments (80 kg N ha -1 of urea as side-row
band, 80 kg N ha -1 of urea as mid-row band,
check/no N (side-row)/P side-row, check/no N (mid-row)/seed placed P).
The treatments were arranged in a randomized complete block design
with four replications. Two anion and cation exchange resin probes
(PRS™) were placed in each plot in the seed-row immediately after
seeding and fertilizing. The probes were allowed to remain in the
field for 2 days and replaced with another set of probes every 4 days
for a total of 14 days until canola emerged. Ammonium-N, nitrate-N and
P supply rates were calculated based on the ion accumulated on the
probes. Urea side-row band treatments (fertilizer N 2.5 cm to
side of every seed-row) had significantly higher cumulative available
N supply rates than mid-row band placement in which fertilizer N was
placed 10 cm from the seed-row in between every second seed-row.
No significant differences were observed in P supply rates. The higher
N rates (120 kg N ha -1) resulted in lower grain
yield in side-row banding than mid-row banding possibly due to
seedling damage. However, the earlier fluxes of N into the seed-row
observed with side-row banding may be an advantage at lower N rates in
N deficient soils.
Key Words
canola, N fertilization, ion-exchange membrane, mid-row band, nitrogen supply rate, PRS™-probes,side-row band
