by Erin Agro A Thesis presented to The University of Guelph In partial fulfilment of requirements for

190 Pages·2014·3.83 MB·English

Optimum Controlled Release Fertilizer Rates for Containerized Nursery Plant
Production in Ontario
by
Erin Agro

A Thesis
presented to
The University of Guelph

In partial fulfilment of requirements
for the degree of
Master of Science
in
Environmental Sciences

Guelph, Ontario, Canada
© Erin Elizabeth Agro, August, 2014
ABSTRACT

OPTIMUM CONTROLLED RELEASE FERTILIZER RATES FOR CONTAINERIZED
NURSERY PLANT PRODUCTION IN ONTARIO

Erin Elizabeth Agro Advisors:
University of Guelph, 2014 Dr. Youbin Zheng
Dr. Jonathan Newman

Controlled release fertilizers (CRF) are the primary method of fertilization for container grown
plants in North American nurseries. Region specific trials examining optimum CRF rates for container
nursery production in Ontario are limited, as most field trials occur in temperate to warm regions of the
United States and use production practices for those areas. This study was conducted to determine
optimum CRF ranges for 17 economically significant container grown plants at three southern Ontario
nurseries (south central, western and eastern) using production practices, fertilizer types and growing
substrate typical to those nurseries. Results of the study indicate that an acceptable range of CRF
application rates can be utilized for each species depending on the production goals, (i.e.: decreased
production time, maximum growth or decreased nutrient leachate). The highest rate in the range produced
maximized growth where the lowest rate ensured marketable quality, but limited the losses of nitrogen
and phosphorus.
ACKNOWLEDGEMENTS

I would like to express my deep gratitude to Dr. Youbin Zheng for his patient guidance, enthusiastic
encouragement and useful critiques of this research work. Youbin, your vast knowledge of horticulture is
astounding, thank you for all of your help over these past two years. What a wonderful education it has
been!
I would also like to thank Dr. Jonathan Newman and Wayne Brown for their advice, assistance,
constructive recommendations and keen editing skills. It is a better thesis thanks to your contributions.
My grateful thanks are also extended to Mary Jane Clark for always offering to help in anyway and being
available to chat through ideas. Also, I am very appreciative of her extra support during the site
measurements.
Thank you to Pieper, Sheridan and Willowbrook nurseries for supplying the space and plants. Chris,
Kathy and Olu, thank you for your help, patience and expertise over these past two year, it has been
gratefully appreciated.
There were several supporting organizations without which, this would never have happened. The
contributions of Agriculture and Agri-Food Canada through the Canadian Agricultural Adaptation
Program (CAAP), Landscape Ontario, and Agrium Advanced Technologies are gratefully appreciated.
Thanks to Gro-Bark (Ontario) Ltd. for providing materials, time and expertise.
Finally, I wish to thank my parents for their never ending support and encouragement throughout my
study.

iii
Table of Contents

ABSTRACT .............................................................................................................................................. ii
ACKNOWLEDGEMENTS ..................................................................................................................... iii
List of Tables ......................................................................................................................................... viii
List of Figures ........................................................................................................................................... x
List of Abbreviations, Symbols and Nomenclature ............................................................................... xvi
Chapter 1 ....................................................................................................................................................... 1
Introduction ............................................................................................................................................... 1
The Canadian Ornamental Nursery Industry ........................................................................................ 5
Containerized Plant Production ............................................................................................................ 5
Nutrient requirements for container grown plants ................................................................................ 7
Nitrogen ............................................................................................................................................ 9
Phosphorus ...................................................................................................................................... 13
Potassium ........................................................................................................................................ 13
Nitrogen Dynamics in Containerized Plants ....................................................................................... 14
Nitrification ..................................................................................................................................... 14
Denitrification ................................................................................................................................. 16
Environmental Concerns over Nitrate and Phosphate Contamination ................................................ 17
Controlled Release Fertilizers ............................................................................................................. 19
Nutrient leaching and CRFs ............................................................................................................ 21
Ornamental Plant Quality.................................................................................................................... 22
Chapter 2 ..................................................................................................................................................... 24
Controlled-release fertilizer application rates for one-gallon container nursery crop production in
southwestern Ontario, Canada ................................................................................................................ 24
Introduction ......................................................................................................................................... 24
Materials and Methods ........................................................................................................................ 25
2012................................................................................................................................................. 25
Plant materials and Treatments ................................................................................................... 25
Experimental design .................................................................................................................... 28
Sampling and Analysis................................................................................................................ 28
Winter injury assessment ............................................................................................................ 30
Nutrient loss calculations ............................................................................................................ 30
iv
2013................................................................................................................................................. 31
Plant material and treatments ...................................................................................................... 31
Experimental design .................................................................................................................... 31
Sampling and analysis ................................................................................................................. 31
Statistical analysis ....................................................................................................................... 32
Results ................................................................................................................................................. 33
2012................................................................................................................................................. 33
Growth response ......................................................................................................................... 33
Winter Injury Assessment ........................................................................................................... 39
Environmental nutrient loss ........................................................................................................ 41
Growing substrate EC and pH .................................................................................................... 43
2013................................................................................................................................................. 46
Growth response ......................................................................................................................... 46
Leaf nutrient content ................................................................................................................... 53
Growing substrate EC and pH .................................................................................................... 53
Discussion ........................................................................................................................................... 57
Conclusion .......................................................................................................................................... 63
Chapter 3 ..................................................................................................................................................... 65
Controlled-release fertilizer application rates for one-gallon container nursery crop production in south
central Ontario, Canada .......................................................................................................................... 65
Introduction ......................................................................................................................................... 65
Materials and Methods ........................................................................................................................ 66
2012................................................................................................................................................. 66
Plant material and treatments ...................................................................................................... 66
Experimental design .................................................................................................................... 69
Sampling and analysis ................................................................................................................. 69
Winter injury assessment ............................................................................................................ 70
Nutrient loss calculations ............................................................................................................ 71
2013................................................................................................................................................. 71
Plant material and treatments ...................................................................................................... 71
Experimental design .................................................................................................................... 72
Sampling and analysis ................................................................................................................. 72
Statistical analysis ....................................................................................................................... 74
v
Results ................................................................................................................................................. 75
2012................................................................................................................................................. 75
Plant growth ................................................................................................................................ 75
Plant nutrient status ..................................................................................................................... 81
Winter injury assessment ............................................................................................................ 83
Environmental nutrient loss ........................................................................................................ 85
Growing substrate pH and EC .................................................................................................... 87
2013................................................................................................................................................. 90
Plant growth ................................................................................................................................ 90
Plant nutrient status ..................................................................................................................... 98
Growing substrate pH and EC .................................................................................................... 98
Discussion ......................................................................................................................................... 102
Conclusion ........................................................................................................................................ 108
Chapter 4 ................................................................................................................................................... 110
Optimal controlled release fertilizer rate for one gallon nursery crop production in south eastern
Ontario, Canada .................................................................................................................................... 110
Introduction ....................................................................................................................................... 110
Materials and Methods ...................................................................................................................... 112
2012............................................................................................................................................... 112
Plant material and treatments .................................................................................................... 112
Experimental design .................................................................................................................. 115
Sampling and analysis ............................................................................................................... 115
Winter Injury Assessment ......................................................................................................... 116
Nutrient loss calculations .......................................................................................................... 117
2013............................................................................................................................................... 118
Plant material and treatments .................................................................................................... 118
Experimental design .................................................................................................................. 118
Sampling and analysis ............................................................................................................... 119
Statistical analysis ..................................................................................................................... 119
Results ............................................................................................................................................... 121
2012............................................................................................................................................... 121
Plant growth .............................................................................................................................. 121
Winter injury assessment .......................................................................................................... 128
vi
Environmental nutrient loss ...................................................................................................... 130
Growing substrate pH and EC .................................................................................................. 132
2013............................................................................................................................................... 135
Plant growth .............................................................................................................................. 135
Growing substrate pH and EC .................................................................................................. 142
Discussion ......................................................................................................................................... 146
Conclusion ........................................................................................................................................ 151
Chapter 5 ................................................................................................................................................... 152
General Discussion and Conclusions .................................................................................................... 152
Going Forward .................................................................................................................................. 154
Expanding the scope ..................................................................................................................... 154
Comparison of cultivars ................................................................................................................ 154
Irrigation ....................................................................................................................................... 155
CRF Formulations ......................................................................................................................... 156
Denitrification ............................................................................................................................... 157
Final thoughts ................................................................................................................................ 157
Literature Cited ..................................................................................................................................... 158
Appendices ............................................................................................................................................ 171
Appendix 1 ........................................................................................................................................ 171

vii
List of Tables

Table 1.1: Distinction in classification and source between the macronutrient and the micronutrient
elements required for adequate plant growth. (Adapted from Mills and Jones, 1996). ............ 9

Table 2.1: Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from Cornus sericea
‘Cardinal’, Weigela florida ‘Alexandra’, Salix purpurea ‘Nana’, Hydrangea paniculata
‘Bombshell’, Hibiscus syriacus ‘Ardens’, and Spiraea japonica ‘Magic Carpet’ grown with
five rates of Polyon®16N-2.6P-10K, 5-6 month controlled-release fertilizer, in 2012.
Eigenvalues for each species, and their percent contribution to the total variation, are listed
at the bottom of the columns. .................................................................................................. 38

Table 2.2: Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from Cornus sericea
‘Cardinal’, Weigela florida ‘Alexandra’, Salix purpurea ‘Nana’, Hydrangea paniculata
‘Bombshell’, Hibiscus syriacus ‘Ardens’, and Spiraea japonica ‘Magic Carpet’ grown with
five rates of Polyon®16N-2.6P-10K, 5-6 month controlled-release fertilizer, in 2013.
Eigenvalues for each species and their percent contribution to the total variation are listed .. at
the bottom of the columns. ...................................................................................................... 51

Table 3.1: Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from six shrub species
grown with five rates of Polyon®19N-1.8P-8.3K , 8-9 month controlled release fertilizer in
2012. Eigenvalues for each species, and their percent contribution to the total variation, are
listed at the bottom of the columns. ...................................................................................... 78

Table 3.2: Post winter injury assessment as evaluated on 3 Jun. 2013 of six ornamental shrubs grown
with five different rates of Polyon®19N-1.8P-8.3K, 8-9 month controlled-release fertilizer,
after overwinter storage (12 Oct. 2012 – 22 Apr. 2013) under a 0.07 mm (3 mil) polyethylene
covered hoop house. ................................................................................................................ 84

Table 3.3: Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from five shrub species
grown with five rates of Polyon®19N-1.8P-8.3K, 8-9 month controlled-release fertilizer in
2013. Eigenvalues for each species, and their percent contribution to the total variation, are
listed at the bottom of the columns. ...................................................................................... 95

Table 4.1 Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from six ornamental
species grown with five rates of Polyon®19N-2.6P- 10.8K , 8-9 month controlled-release
fertilizer in 2012. Eigenvalues for each species, and their percent contribution to the total
variation, are listed at the bottom of the columns. ............................................................... 125
viii
Table 4.2: Winter injury assessment as evaluated on 7 Jun. 2013 of Hydrangea macropylla ‘Penny
Mac’, Spiraea japonica ‘Magic Carpet’, Hemerocallis ‘Stella d’Oro’, Hibiscus syriacus
‘Woodbridge’, Buxus ‘Green Velvet’, and Syringa meyeri ‘Palibin’ grown with five
different rates of Polyon®19N-2.6P-10.8K, 8-9 month controlled-release fertilizer after
overwinter storage (19 Oct. 2012 – 26 Apr. 2013) under a 0.07 mm (3 mil) white
polyethylene covered hoop house. ........................................................................................ 129

Table 4.3: Eigenvectors (V) and loadings (W) from principal component axes 1 and 2 (PC 1 and PC 2)
from the principal component analysis (PCA) of growth parameters from Hydrangea
macropylla ‘Penny Mac’, Spiraea japonica ‘Magic Carpet’, Hemerocallis ‘Stella d’Oro’,
Hibiscus syriacus ‘Woodbridge’, Buxus ‘Green Velvet’, and Syringa meyeri . ‘Palibin’grown
with five rates of Polyon®19N-2.6P- 10.8K, 8-9 month controlled-release fertilizer in .. 2013.
Eigenvalues for each species, and their percent contribution to the total variation, are listed at
the bottom of the columns. .................................................................................................... 140

ix
List of Figures

Fig. 1.1: A typical yield response curve between N supply and plant growth depicting the three
well-defined regions associated with increased N supply; (1) the deficient range, where
any increase in the amount of nitrogen supplied will result in increasing plant growth; (2)
the adequate range, where plant growth has reached asymptotic behaviour and any
additional increase in N will not alter the growth and (3) the toxic range, where any further
increase in N will results in a decrease of plant growth. Adapted from Chen et al. (2001).
12

Fig. 2.1: Daily average (solid line), minimum (lower dotted line), maximum (upper dotted line) and 10
year historical daily average (red line) outdoor air temperatures and total rainfall from 3 Jul.
2012 to 5 Oct. 2012 (A) and 3 Jun. 2013 – 28 Aug. 2013 (B) at the London Central Weather
Station (Lat. 43°02'00" N, Long. 81°09'00 W) (Adapted from Environment Canada, 2013a).
The black horizontal line on air temperature graph indicates the temperature at which the
product longevity of Polyon®16N-2.6P-10K, 5-6 month controlled-release fertilizer was
determined by Agrium Advanced Technologies Inc............................................................... 27

Fig. 2.2: Leaf area, shoot dry weight and growth index as measured in Oct. 2012 of Cornus sericea
‘Cardinal’ (●), Spiraea japonica ‘Magic Carpet’(▼), Hydrangea paniculata ‘Bombshell’
(▲), Hibiscus syriacus ‘Ardens’(○), Salix purpurea ‘Nana’ (♦) and Weigela florida
‘Alexandra’ (□) after growth with five rates of Polyon®16N-2.6P-10K, 5-6 month
controlled-release fertilizer. Data are the means of four replicates ± SE. If line is not shown,
the relationship is not significant (P > 0.05). .......................................................................... 35

Fig. 2.3: Overall plant quality as measured on 5 Oct. 2012 for Cornus sericea ‘Cardinal’, Weigela
florida ‘Alexandra’, Salix purpurea ‘Nana’, Hydrangea paniculata ‘Bombshell’, Hibiscus
syriacus ‘Ardens’, and Spiraea japonica ‘Magic Carpet’ grown with five rates of
Polyon®16N-2.6P-10K, 5-6 month controlled-release fertilizer. Data are means ± SE (n = 4).
Symbols baring the same letter are not significantly different for each species at P < 0.05,
according to Tukey’s multiple comparison test. According to the grower’s opinion, the ‘>’
indicates the lowest acceptable CRF rate for that species. ...................................................... 37

Fig. 2.4 : Response of ‘plant growth’ (PC 1) to application rate of Polyon®16N-2.6P-10K , 5-6 month
controlled-release fertilizer, for Cornus sericea ‘Cardinal’, Weigela florida ‘Alexandra’, . Salix
purpurea ‘Nana’, Hydrangea paniculata ‘Bombshell’, Hibiscus syriacus ‘Ardens’, and
Spiraea japonica ‘Magic Carpet’ grown in 2012. Data are the means of four replicates ± SE. If
line is not shown, the relationship is not significant (P > 0.05). ................................................. 40

Fig. 2.5: Effect of CRF application rate on amount of N (●) and P (▲) lost to the environment
(g·pot-1) from Cornus sericea ‘Cardinal’, Weigela florida ‘Alexandra’, Salix purpurea
‘Nana’, Hydrangea paniculata ‘Bombshell’, Hibiscus syriacus ‘Ardens’, and Spiraea
x