Storage of Pine Tree Substrate Influences Plant Growth, Nitrification, and Substrate Properties

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dc.contributor.authorTaylor, Linda Leaen
dc.contributor.committeechairNiemiera, Alexander X.en
dc.contributor.committeememberWright, Robert D.en
dc.contributor.committeememberHarris, James Rogeren
dc.contributor.committeememberEvanylo, Gregory K.en
dc.contributor.committeememberThomason, Wade E.en
dc.contributor.departmentHorticultureen
dc.date.accessioned2014-03-14T21:23:09Zen
dc.date.adate2011-12-05en
dc.date.available2014-03-14T21:23:09Zen
dc.date.issued2011-10-28en
dc.date.rdate2011-12-05en
dc.date.sdate2011-11-15en
dc.description.abstractPine tree substrate (PTS) is a relatively new substrate for container crop production. There are no detailed studies that elucidate how storage time impacts PTS chemical, physical, and biological aspects. The objective of this research was to determine how PTS storage time influenced PTS chemical and physical properties, nitrification, and plant growth. Pine tree substrate was manufactured by hammer-milling chips of loblolly pine trees (Pinus taeda L.) through two screen sizes, 4.76 mm (PTS) and 15.9 mm amended with peat (PTSP). PTS and PTSP were amended with lime at five rates. A peat-perlite mix (PL) served as a control treatment. Prepared substrates were placed in storage bags and stored in an open shed in Blacksburg, Virginia. Subsamples were taken at 1, 42, 84, 168, 270, and 365 days. At each subsampling day, twelve 1-L containers were filled with each substrate. Six containers were left fallow and six were planted with marigold (Tagetes erecta L. "Inca Gold") seedlings. Substrate was also collected from select treatments for Most Probable Number assays to estimate density of nitrifying microorganisms, and for chemical and physical property analyses. Pour-through extracts were collected from fallow containers at 0, 2, and 4 weeks, and from marigold containers at harvest for determination of pH, electrical conductivity, ammonium-N and nitrate-N. At harvest, marigold height, width, and dry weight were measured. At least 1 kg·m-3 lime for PTS, and 2 to 4 kg·m-3 lime for PTSP were needed to maintain pH values ≥ 5.5 for 365 days. Bound acidity of unlimed PTS increased but cation exchange capacity for unlimed PTS and PTSP decreased over 365 days. Carbon to nitrogen ratio and bulk density values were unchanged over time in all treatments. There were minor changes in particle size distribution for limed PTS and unlimed and limed PTSP. Marigold growth in PTS and PTSP was ≥ PL in all limed treatments, except at day 1. Nitrite-oxidizing microorganisms were present and nitrification occurred in PTS and PTSP at all subsampling days. Pine tree substrate is relatively stable in storage, but pH decreases, and lime addition may be necessary to offset this decrease.en
dc.description.degreePh. D.en
dc.identifier.otheretd-11152011-125714en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11152011-125714/en
dc.identifier.urihttp://hdl.handle.net/10919/40342en
dc.publisherVirginia Techen
dc.relation.haspartTaylor_LL_D_2011.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectbound acidityen
dc.subjectelectrical conductivityen
dc.subjectcarbon to nitrogen ratioen
dc.subjectbulk densityen
dc.subjectLoblolly pineen
dc.subjectPinus taeda L.en
dc.subjectparticle size distributionen
dc.subjectTagetes erecta L. 'Inca Gold'en
dc.subjectmarigolden
dc.subjectpHen
dc.subjectcation exchange capacityen
dc.subjectammoniumen
dc.subjectnitrateen
dc.subjectMost Probable Numberen
dc.titleStorage of Pine Tree Substrate Influences Plant Growth, Nitrification, and Substrate Propertiesen
dc.typeDissertationen
thesis.degree.disciplineHorticultureen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en
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