Location: Soil Dynamics ResearchTitle: Results using flue gas desulfurization gypsum in soilless substrates for greenhouse crops Author
|Brown, B - Auburn University|
|Sibley, J - Auburn University|
|Pickens, J - Auburn University|
|Torbert, Henry - Allen|
Submitted to: Southern Nursery Association Research Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/9/2018
Publication Date: 1/9/2018
Citation: Brown, B.W., Sibley, J.L., Pickens, J.M., Torbert III, H.A. 2018. Results using flue gas desulfurization gypsum in soil-less substrates for greenhouse crops. In: Proceedings of the Southern Nursery Association Research Conference, January 8-9, 2018, Baltimore, Maryland. CDROM.
Interpretive Summary: Recent availability of Flue Gas Desulfurization gypsum (FGDG) has led to interested in its possible use in horticulture greenhouse production. Three studies were conducted to determine the effects of increasing rates of FGDG on six greenhouse crops. While positive responses were noted, more research is needed regarding the efficacy of gypsum use.
Technical Abstract: Recent availability of Flue Gas Desulfurization gypsum (FGDG) has led to interested in its possible use in horticulture greenhouse production. Three studies were conducted to determine the effects of increasing rates of FGDG on six greenhouse crops. In the first study, substrates (6:1 pine bark:sand) for two greenhouse crops: zonal geranium (Pelargonium x hortorum) and petunia (Petunia x hybrida) were pre-plant incorporated with 4 rates of FGDG and 2 rates of dolomitic limestone. A second study incorporated seven rates of FGDG and 1 dolomitic lime for ‘poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch) and three species of fern: Nephrolepis obliterata. A third study with poinsettias used similar and higher rates of FGDG . Cell wall stability and stem strength are often attributed to calcium, poinsettias were included to evaluate calcium effect of stem breakage in poinsettia, often a problem in poinsettia production. In study 1, Geranium growth index (GI) increased as FGDG levels increased and dry weight increased slightly. Petunia GI was significantly less as levels of FGDG increased and GI increased at the lowest FGDG rate compared to the control, however; no differences were observed for fresh or dry shoot weights. Based on the results of this study, geranium greenhouse production may benefit from incorporating FGDG when using pine bark-based substrate. In study 2, both fern species had varying responses for GI. Means of growth indices varied across all treatments, and means were similar for the control. In study 3, poinsettia dry weights varied across treatments with the maximum observed dry weight at the FGDG rate of 48.95 kg/m3. During both experiments, sufficiency levels were within recommended ranges across all treatments and there was no observable bract necrosis or nutrient deficiency or toxicity observed on any treatment. Plants at the higher rates of gypsum did not dry out between watering compared to the control and the lowest gypsum rate. In study 3, there was a slight increase in stem strength at FGDG. While positive responses were noted, more research is needed regarding the efficacy of gypsum use.