Page 269 - PC2019 Program & Proceedings

PLANT CANADA 2019

P111. Blue light can promote flowering of bedding plants when associated with low phytochrome
activity
Kong, Y.; K. Schiestel; Y. Zheng
University of Guelph

To clarify the flowering response to blue light associated with varying phytochrome activity, the
flowering traits of petunia, calibrachoa, geranium, and marigold were investigated under six light quality
treatments: (1) R, “pure” red light; (2) B, “pure” blue light; and (3) BRF0, (4) BRF2, (5) BRF4, and (6)
BRF6, “unpure” blue light created by mixing B with 6% R, and further adding far-red light of 0, 2, 4, and
−2
−1
6 μmol m s , respectively. B and BRF6 promoted flowering compared to R and BRF0, as demonstrated
by an earlier flowering time for petunia and calibrachoa; and showed a greater flowering index, more
visible flower buds, and more opened flowers for geranium and marigold. The promotion effect of
“unpure” blue light on these traits increased following the order of BRF0, BRF2, BRF4 and BRF6, which
varied in sensitivity among plant species. Also, a similar pattern of promotion by blue light was found in
the flower size for calibrachoa, and in the canopy size for all the species. The calculated phytochrome
photostationary state, an indication of phytochrome activity, was higher for R (0.89) than B (0.49), and
decreased gradually for “unpure” blue light treatments: BRF0 (0.68), BRF2 (0.65), BRF4 (0.63), and
BRF6 (0.60). This suggests that “blue” light associated with lower phytochrome activity can promote
flowering, despite having a varying level of sensitivity among species.

Yun Kong (ky0257@gmail.com)

P112. NLOS-OG: A nitrogen simulation tool for managing organic greenhouses
2
*1
2
2
Dion, P. ; M. Thériault ; D. Hunt ; S. Bittman ; S. Pepin ; M. Dorais
1
1
1 Laval University
2 Agriculture and Agrifood Canada
Because of the complexity of the nitrogen (N) cycle and the diversity of N molecules in the soil, N
fertilization management is based on complex calculations and considerations. For organic farming, lack
of data and management tools that predict N availability from organic fertilizers leads to overfertilization
which results in both buildup of salinity and leaching of N. Better prediction of N availability following
application of organic fertilizers is crucial in advancing sustainable organic horticulture. Our objective
was to adapt a field-based N simulation tool to organic greenhouse production.

First, we adapted the NLOS model to organic greenhouse production by introducing N mineralization
equations obtained from incubation experiments on common organic fertilizers (pelleted poultry manure
and blood, feather, shrimp and alfalfa meals). Second, we monitored N flows in four organic greenhouse
crops (two cucumber, one tomato and one pepper) to validate the model.

The current version of NLOS-OG accurately predicts N mineralization from several organic fertilizers. It
also predicts N availability to greenhouse crops grown in native mineral soil. However, the model
underestimates N availability to crops grown in containerized growing media. Further research will focus
on the effect of water dynamics on N availability in containerized organic greenhouses. The web-based
NLOS-OG, with a user-friendly interface, is available
at https://exchange.iseesystems.com/public/pierrepauldion/nlos-og/ and can be used to assist growers to
plan N fertilization in organic greenhouses.

Pierre-Paul Dion (pierre-paul.dion.1@ulaval.ca)

Page 267 of 339