Semester of Graduation

Fall 2023

Degree

Master of Science (MS)

Department

Plant, Environmental and Soil Sciences

Document Type

Thesis

Abstract

The Covid-19 pandemic and ensuing lockdowns led to an increase in revenue and production for green industry products in early 2020. In Study 1. an evaluation of fertigation (liquid feed, quick release) and controlled release fertilizers (CRFs, slow release) were applied to container-grown (7 gallon) live oak (Quercus virginiana) and Nutall oak (Quercus nuttallii) trees (100% Liquid feed, 0% CRF, 67% Liquid feed, 33% CRF, 33% Liquid feed, 67% CRF, 100% Liquid feed, 0% CRF). Live oak trees fertilized with CRFs had increased stem calipers (>30%). Nuttall stem caliper and height were significantly increased by 62% and 58%, respectively, with substrate incorporation of CRFs. Live oak tree height was increased by 35% and stem caliper when CRFs were incorporated. In study 2, the effect of alkaline water quality on live oak tree production was initiated at a nursery in Point Coupee Parish. Ca and Mg sources were used to study the impact of water quality on live oak tree container-growth and study the benefits of using different rates of lime and gypsum [0% dolomitic lime (Ca, Mg), 100% gypsum (Ca) + Epsom salt (Mg), 25% dolomitic lime (Ca, Mg), 75% gypsum (Ca) + Epsom salt (Mg), 50% dolomitic lime (Ca, Mg), 50% gypsum (Ca) + Epsom salt (Mg), 75% dolomitic lime (Ca, Mg), 25% gypsum (Ca) + Epsom salt (Mg), 100% dolomitic lime (Ca, Mg) + 0% dolomitic lime]. Live oak tree growth measurements increased with the reduction of dolomitic lime and increase of Epsom salt and gypsum applications. Leaf Na content was significantly reduced using higher proportions of gypsum and Epsom salt. Soil pH was also reduced by more than 1 pH unit after a growing season. Soil pH did increase when irrigated with highly alkaline water. Growers using alkaline water need to manage irrigation water and soil pH and consider using gypsum and Epsom salt reducing dolomitic lime rates as a source of Ca and Mg. All Ca and Mg sources provided greater than the threshold levels of leaf Ca and Mg content.

Date

10-31-2023

Committee Chair

Bush, Edward

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