Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)

The first objective was to evaluate wood components for differences in nitrogen (N) immobilization and effects on substrate physical properties. The second objective was to evaluate peat substrates amended with pine wood components for effects on plant growth, shoot tissue N, and fertigation practic...

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Main Authors: Ryan W. Dickson, Kalyn M. Helms, Brian E. Jackson, Leala M. Machesney
Format: Article
Language:English
Published: American Society for Horticultural Science (ASHS) 2022-01-01
Series:HortScience
Subjects:
Online Access:https://journals.ashs.org/hortsci/view/journals/hortsci/57/2/article-p304.xml
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author Ryan W. Dickson
Kalyn M. Helms
Brian E. Jackson
Leala M. Machesney
author_facet Ryan W. Dickson
Kalyn M. Helms
Brian E. Jackson
Leala M. Machesney
author_sort Ryan W. Dickson
collection DOAJ
description The first objective was to evaluate wood components for differences in nitrogen (N) immobilization and effects on substrate physical properties. The second objective was to evaluate peat substrates amended with pine wood components for effects on plant growth, shoot tissue N, and fertigation practices during production. Substrates consisted of a coarse sphagnum peat blended with four types of processed pine wood at rates of 15%, 30%, 45%, and 60% (by volume). For comparison, peat was also blended with an aged pine bark, perlite, and coconut coir. Nitrogen immobilization was measured for individual components, except perlite. Individual components and blended substrates were evaluated for particle size distribution, total air porosity, container capacity, and dry bulk density. In a greenhouse experiment, petunia (Petunia × hybrida Vilm.-Andr.) were grown in hanging basket containers with each substrate blend as well as 100% peat, which served as a nonblended control substrate, and fertilized at each irrigation with 200 mg·L−1 N. Blended component and blend percent interacted in effects on all measured substrate physical properties; however, physical properties of all substrate blends were considered adequate for horticultural purposes. In the laboratory, pine bark immobilized 9% of total N supplied, whereas the remaining pine wood components immobilized <5% of total N. In the greenhouse experiment, blend component influenced shoot growth and flowering, which were greatest for petunia grown in 100% peat. Increasing the blend percent of all components decreased shoot growth and flowering with all blended components. Blended substrates had minimal effects on number of fertigation events, and substrate treatments differed by a maximum of three fertigation events per container over a 56-d period. This study illustrates the challenges of measuring N immobilization because results from the laboratory were not consistent with plant performance in the greenhouse. Increasing blends of each substrate (including perlite) were also observed to interact with fertigation practices and therefore applied N, tissue N, shoot dry weight, and total N uptake. As a practical conclusion from this study, peat incorporated with 60% wood fiber increased the risk of reduced plant growth and N uptake, but this risk was lower as the blend percentage decreased. In addition, other analytical methods to test N immobilization, such as microbial respiration, should be further explored.
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spelling doaj.art-eba52820db864db2a13a2a1f39cbd34d2022-12-22T04:10:10ZengAmerican Society for Horticultural Science (ASHS)HortScience2327-98342022-01-01572304311https://doi.org/10.21273/HORTSCI16177-21Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)Ryan W. DicksonKalyn M. HelmsBrian E. JacksonLeala M. MachesneyThe first objective was to evaluate wood components for differences in nitrogen (N) immobilization and effects on substrate physical properties. The second objective was to evaluate peat substrates amended with pine wood components for effects on plant growth, shoot tissue N, and fertigation practices during production. Substrates consisted of a coarse sphagnum peat blended with four types of processed pine wood at rates of 15%, 30%, 45%, and 60% (by volume). For comparison, peat was also blended with an aged pine bark, perlite, and coconut coir. Nitrogen immobilization was measured for individual components, except perlite. Individual components and blended substrates were evaluated for particle size distribution, total air porosity, container capacity, and dry bulk density. In a greenhouse experiment, petunia (Petunia × hybrida Vilm.-Andr.) were grown in hanging basket containers with each substrate blend as well as 100% peat, which served as a nonblended control substrate, and fertilized at each irrigation with 200 mg·L−1 N. Blended component and blend percent interacted in effects on all measured substrate physical properties; however, physical properties of all substrate blends were considered adequate for horticultural purposes. In the laboratory, pine bark immobilized 9% of total N supplied, whereas the remaining pine wood components immobilized <5% of total N. In the greenhouse experiment, blend component influenced shoot growth and flowering, which were greatest for petunia grown in 100% peat. Increasing the blend percent of all components decreased shoot growth and flowering with all blended components. Blended substrates had minimal effects on number of fertigation events, and substrate treatments differed by a maximum of three fertigation events per container over a 56-d period. This study illustrates the challenges of measuring N immobilization because results from the laboratory were not consistent with plant performance in the greenhouse. Increasing blends of each substrate (including perlite) were also observed to interact with fertigation practices and therefore applied N, tissue N, shoot dry weight, and total N uptake. As a practical conclusion from this study, peat incorporated with 60% wood fiber increased the risk of reduced plant growth and N uptake, but this risk was lower as the blend percentage decreased. In addition, other analytical methods to test N immobilization, such as microbial respiration, should be further explored.https://journals.ashs.org/hortsci/view/journals/hortsci/57/2/article-p304.xmlbarkfoirpine wood fiberpine tree substrateperlitefloriculture
spellingShingle Ryan W. Dickson
Kalyn M. Helms
Brian E. Jackson
Leala M. Machesney
Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
HortScience
bark
foir
pine wood fiber
pine tree substrate
perlite
floriculture
title Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
title_full Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
title_fullStr Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
title_full_unstemmed Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
title_short Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)
title_sort evaluation of peat blended with pine wood components for effects on substrate physical properties nitrogen immobilization and growth of petunia petunia hybrida vilm andr
topic bark
foir
pine wood fiber
pine tree substrate
perlite
floriculture
url https://journals.ashs.org/hortsci/view/journals/hortsci/57/2/article-p304.xml
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