Examining the Impact of Silicon Substrate Amendments and Biochar Aggregates on Plant Growth and Nutrient Uptake on Greenhouse Produced Crops
Patrick Veazie, MS Seminar
Wednesday, February 21, 2024, 9:00 am
(Under the direction of Dr. Brian Whipker, Chair)

Location: 121 Kilgore Hall / Hybrid
Join Zoom Meeting: https://ncsu.zoom.us/j/94536602170?pwd=Rm0ranhCbDh6Q2ZYTlFmV2YrazJLUT09
Meeting ID:  945 3660 2170
Passcode:  780482 

Veazie.Abstr.pdf

Abstract:
Greenhouse substrates traditionally utilize perlite or bark as aggregates to promote drainage within a substrate. However, alternative substrate components such as coconut coir, wood chip, wood fiber, and biochar, have been evaluated as alternative substrate components. Biochar is a charred feedstock material similar to charcoal that is the result of pyrolysis, gasification, or hydrothermal carbonization. Recently, biochar has been evaluated as an alternative soil and greenhouse substrate amendment with promising success as an alternative to traditional aggregates. Additionally, research examining calcium silicate as a substrate amendment has demonstrated it to be an effective alternative to foliar spray applications to increase silicon (Si) concentrations within a plant. However, the impact of these substrate amendments on the physical and chemical properties of soilless substrates and plant growth has not been examined together. Therefore, the objective of this work was to classify the cultural parameters with biochar as an alternative aggregate to perlite and silicon substrate amendments in greenhouse production. First, the response of Si on heavy metal micronutrient uptake and plant growth for greenhouse-cultivated cannabis at varying Si substrate amendments was evaluated. The results of this study suggest that plants that receive a Si substrate amendment can prevent toxic accumulation of micronutrients in various plant parts including the roots, most recently mature leaves, and floral material. A second objective of examining plant growth and substrate chemical properties when amending a substrate with both Si substrate amendment and biochar aggregate. Plant dry weight or plant growth metrics were not significantly impacted when both substrate amendments were incorporated for tomato (Solanum lycopersicum), pepper (Capsicum annum), French marigold (Tagetes patula), or cannabis. Additionally, when examining the efficacy of paclobutrazol, a GA inhibitor plant growth regulator, was not affected by the incorporation of biochar in soilless substrates. Drench concentrations of paclobutrazol exhibited similar control for poinsettia, pansy, and begonia up to 15% or 30% biochar when compared to similar perlite aggregate substrates. This work suggests that biochar is a suitable alternative to perlite and no changes in cultural practices are needed when biochar is incorporated up to 30% for greenhouse substrates.