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