Articles
Reflective groundcover improves return bloom and yield in Granny Smith apple under protective netting
Article number
1337_56
Pages
409 – 416
Language
English
Abstract
Light is essential for flower bud formation in apple trees and is positively correlated with return bloom.
Worldwide, apple trees are increasingly being grown under protective netting to prevent fruit sunburn and protect trees from hail damage.
However, return bloom can be negatively affected under protective nets from the resulting low light conditions.
Reflective groundcovers have been previously reported to increase the amount of reflected and diffuse photosynthetically active radiation (PAR), particularly in the lower and interior tree canopy.
Our objective was to test whether reflective groundcover can improve light penetration into the tree canopy and thereby improve return bloom and yield under protective netting.
The trial was conducted in 2018 and 2019 on a Granny Smith orchard on M29 rootstock; trees were trained on 4-wire tall spindle trellis and spaced 0.9×3.6 m.
The trial was conducted under a 17% white neutral protective net; the treatments were protective netting with a reflective groundcover and protective netting without reflective groundcover (grass control). The trial design was a randomized complete block design with four replications per treatment.
The amount of reflected and diffuse photosynthetically active radiation (PAR) was measured 1.5 m above the ground during the growing season.
Yield, and fruit quality was assessed at harvest.
Return bloom was assessed in 2019 by counting the number of flower clusters from two trees in each treatment replication.
Reflective groundcover significantly increased the amount of reflected and diffuse PAR in the center of the drive row and the tree canopy compared to the grass control.
Reflective groundcover significantly increased return bloom compared to the control.
Although not statistically different, yield was numerically higher (22.6% greater) when reflective groundcover was used compared to the control.
There was no difference in total soluble solids and titratable acidity between the reflective groundcover and the control.
In conclusion, using reflective fabrics under protective netting could be a potential solution to improve return bloom and yield in apple production.
Worldwide, apple trees are increasingly being grown under protective netting to prevent fruit sunburn and protect trees from hail damage.
However, return bloom can be negatively affected under protective nets from the resulting low light conditions.
Reflective groundcovers have been previously reported to increase the amount of reflected and diffuse photosynthetically active radiation (PAR), particularly in the lower and interior tree canopy.
Our objective was to test whether reflective groundcover can improve light penetration into the tree canopy and thereby improve return bloom and yield under protective netting.
The trial was conducted in 2018 and 2019 on a Granny Smith orchard on M29 rootstock; trees were trained on 4-wire tall spindle trellis and spaced 0.9×3.6 m.
The trial was conducted under a 17% white neutral protective net; the treatments were protective netting with a reflective groundcover and protective netting without reflective groundcover (grass control). The trial design was a randomized complete block design with four replications per treatment.
The amount of reflected and diffuse photosynthetically active radiation (PAR) was measured 1.5 m above the ground during the growing season.
Yield, and fruit quality was assessed at harvest.
Return bloom was assessed in 2019 by counting the number of flower clusters from two trees in each treatment replication.
Reflective groundcover significantly increased the amount of reflected and diffuse PAR in the center of the drive row and the tree canopy compared to the grass control.
Reflective groundcover significantly increased return bloom compared to the control.
Although not statistically different, yield was numerically higher (22.6% greater) when reflective groundcover was used compared to the control.
There was no difference in total soluble solids and titratable acidity between the reflective groundcover and the control.
In conclusion, using reflective fabrics under protective netting could be a potential solution to improve return bloom and yield in apple production.
Authors
G. Mupambi, T. Schmidt, N. Valverdi, H. Camargo-Alvarez, M. Reid, L. Kalcsits
Keywords
fruit quality, Malus domestica Borkh, light penetration, tree canopy
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