About

Alex Niemiera is a professor in the School of Plant and Environmental Sciences at Virginia Tech, with a primary focus on horticulture, landscape plants, and plant-environment interactions. He holds a Ph.D. and M.S. in Horticulture from Virginia Polytechnic and State University, and a B.S. in Horticulture from the University of Kentucky. His academic appointment involves a 90% teaching and 10% extension split, where he teaches six courses annually that mainly explore the interaction between horticultural species and humans. His expertise includes woody landscape plants, plant-environment interactions, cannabis science, industry and culture, plants in urban communities, and plant nutrition. Niemiera has contributed significantly to research on nutrient management, especially phosphorus and nitrogen in nursery and containerized crop production, and has been recognized with awards such as the Virginia Tech William E. Wine Award for Teaching Excellence and the Teaching Award of Merit from Gamma Sigma Delta. His work encompasses both research and education, aiming to improve horticultural practices and understanding of plant-environment dynamics.

Research topics

• Ecology
• Biology
• Botany
• Chemistry
• Horticulture
• Geography
• Agronomy
• Environmental science
• Animal science
• Mineralogy

Selected publications

• Growth and Quality Response of Four Container-grown Nursery Crop Species to Low-phosphorus Controlled-release Fertilizer

  HortTechnology · 2022 · 1 citations

  • Horticulture
  • Biology
  • Botany

  The amount of phosphorus (P) conventionally recommended and applied to container nursery crops commonly exceeds plant requirements, resulting in unused P leaching from containers and potentially contributing to surface water impairment. An experiment was replicated in the Middle Atlantic Coastal Plain (MACP) and Ridge and Valley ecoregions of Virginia to compare the effect of a low-P controlled-release fertilizer (CRF, 0.9% or 1.4% P depending on species) vs. a conventional CRF formulation (control, 1.7% P) on plant shoot growth, crop quality, and substrate nutrient concentrations of four species: ‘Natchez’ crape myrtle ( Lagerstroemia indica × Lagerstroemia fauriei ), ‘Roblec’ Encore azalea ( Rhododendron hybrid), ‘Radrazz’ Knock Out rose ( Rosa hybrid), and ‘Green Giant’ arborvitae ( Thuja plicata × Thuja standishii ). In both ecoregions, the low-P CRF resulted in 9% to 26% lower shoot dry weight in all four species compared with those given the conventional formulation, but quality ratings for two economically important species, ‘Radrazz’ Knock Out rose and ‘Green Giant’ arborvitae, were similar between treatments. When fertilized with the low-P CRF, ‘Roblec’ Encore azalea and ‘Natchez’ crape myrtle in both ecoregions, and ‘Green Giant’ arborvitae in the MACP ecoregion had ∼56% to 75% lower substrate pore-water P concentrations than those that received the control CRF. Nitrate-nitrogen (N) concentrations in substrate pore water at week 5 were more than six times greater in control-fertilized plants than in those that received a low-P CRF, which may have been a result of the greater urea-N content or the heterogeneous nature of the low-P CRFs. Lower water-extractable pore-water P and N indicate less environmental risk and potentially increased crop efficiency. Our results suggest low-P CRFs can be used to produce certain economically important ornamental nursery crops successfully without sacrificing quality; however, early adopters will need to evaluate the effect of low-P CRFs on crop quality of specific species before implementing on a large scale.

  DOI

• Using Compost in Your Landscape

  2021

  1st authorCorresponding
  • Environmental science
  • Geography
  • Ecology

  Compost is produced when organic matter, such as garden and lawn waste, is broken down by bacteria and fungi. When added to soil it improves soil structure; sandy soils will hold water better while clays will drain faster. Compost also promotes a biologically healthy soil by providing food for earthworms, soil insects, and beneficial microorganisms.

• Dolomite and Micronutrient Fertilizer Affect Phosphorus Fate When Growing Crape Myrtle in Pine Bark

  HortScience · 2020 · 8 citations

  • Chemistry
  • Horticulture
  • Animal science

  Soilless substrates are routinely amended with dolomite and sulfate-based micronutrients to improve fertility, but the effect of these amendments on phosphorous (P) in substrate pore-water during containerized crop production is poorly understood. The objectives of this research were as follows: compare the effects of dolomite and sulfate-based micronutrient amendments on total P (TP), total dissolved P (TDP), orthophosphate P (OP), and particulate P (PP; TP − TDP) concentrations in pour-through extracts; to model saturated solid phases in substrate pore-water using Visual MINTEQ; and to assess the effects of dolomite and micronutrient amendments on growth and subsequent P uptake efficiency (PUE) of Lagerstroemia L. ‘Natchez’ (crape myrtle) potted in pine bark. Containerized crape myrtle were grown in a greenhouse for 93 days in a 100% pine bark substrate containing a polymer-coated 19N–2.6P–10.8K controlled-release fertilizer (CRF) and one of four substrate amendment treatments: no dolomite or micronutrients (control), 2.97 kg·m −3 dolomite (FL); 0.89 kg·m −3 micronutrients (FM); or both dolomite and micronutrients (FLM). Pour-through extracts were collected approximately weekly and fractioned to measure pore-water TP, TDP, and OP and to calculate PP. Particulate P concentrations in pour-through extracts were generally unaffected by amendments. Relative to the control, amending pine bark with FLM reduced water-extractable OP, TDP, and TP concentrations by ≈56%, had no effect on P uptake efficiency, and resulted in 34% higher total dry weight (TDW) of crape myrtle. The FM substrate had effects similar to those of FLM on plant TDW and PUE, and FM reduced pore-water OP, TDP, and TP concentrations by 32% to 36% compared with the control. Crape myrtle grown in FL had 28% lower TDW but pour-through OP, TDP, and TP concentrations were similar to those of the control. Chemical conditions in FLM were favorable for precipitation of manganese hydrogen phosphate (MnHPO 4 ), which may have contributed to lower water-extractable P concentrations in this treatment. This research suggests that amending pine bark substrate with dolomite and a sulfate-based micronutrient fertilizer should be considered a best management practice for nursery crop production.

  DOI

Frequent coauthors

• Robert D. Wright

  14 shared

• Jacob H. Shreckhise

  Agricultural Research Service

  7 shared

• James S. Owen

  Agricultural Research Service

  6 shared

• Rick M. Bates

  6 shared

• J. Roger Harris

  5 shared

• Nabila S. Karam

  Jordan University of Science and Technology

  4 shared

• James E. Altland

  Agricultural Research Service

  4 shared

• Linda L. Taylor

  Virginia Tech

  3 shared

Awards & honors

• Virginia Tech William E. Wine Award for Teaching Excellence…
• Teaching Award of Merit, Gamma Sigma Delta (Virginia Tech Ch…
• Virginia Tech Award for Excellence in Career Advising (2014)

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