Soil Assessment of Lockerly Arboretum: Density and Water Availability at Potential Sites for New Collections
Abstract
Lockerly Arboretum in Milledgeville, GA is looking to expand their horticultural collection with two new exhibits. They need a comprehensive soil assessment of two potential sites, Forest Hill and Sand Hill. Both study sites are visible from the most frequently used parts of the property, yet each is home to a different soil series, Vance and Enon, respectively. The NRCS Web Soil Survey was used to map the property for soil data. Soil cores and loose samples were taken from the top six inches of both sites and used to experimentally estimate physical characteristics including texture, bulk density, porosity, and volumetric water content (VWC) at field capacity. Data collected within the same site were averaged to provide indications of each soil’s potential as a medium for plant growth. Textural analysis was performed by observing the rate at which sample particles fell from aqueous suspension in accordance with Stoke’s Law; hydrometer readings showed samples from both sites to mostly exhibit sandy clay loam texture. Bulk density was determined by measuring solid mass and total volume of soil core samples. Porosity was calculated with a commonly assumed particle density of 2.65 g/cm3. Results showed a 1.56 and 1.40 g/cm3 bulk density and a 41.0 and 47.2% porosity, respectively. To assess water availability, saturated soil samples were drained via a hanging water column simulating field capacity conditions to estimate VWC (28.3 and 34.4%, respectively). Results show relatively high water retention capacity at the surface layer due to elevated clay content, as determined by textural analysis. This is associated with low permeability, which may restrict water availability and root growth for plants and provide challenges during cultivation of new collections. Recommendations include application of organic material, such as compost, which may serve to increase water and nutrient availability to plants through vulnerable developmental stages.
Soil Assessment of Lockerly Arboretum: Density and Water Availability at Potential Sites for New Collections
Lockerly Arboretum in Milledgeville, GA is looking to expand their horticultural collection with two new exhibits. They need a comprehensive soil assessment of two potential sites, Forest Hill and Sand Hill. Both study sites are visible from the most frequently used parts of the property, yet each is home to a different soil series, Vance and Enon, respectively. The NRCS Web Soil Survey was used to map the property for soil data. Soil cores and loose samples were taken from the top six inches of both sites and used to experimentally estimate physical characteristics including texture, bulk density, porosity, and volumetric water content (VWC) at field capacity. Data collected within the same site were averaged to provide indications of each soil’s potential as a medium for plant growth. Textural analysis was performed by observing the rate at which sample particles fell from aqueous suspension in accordance with Stoke’s Law; hydrometer readings showed samples from both sites to mostly exhibit sandy clay loam texture. Bulk density was determined by measuring solid mass and total volume of soil core samples. Porosity was calculated with a commonly assumed particle density of 2.65 g/cm3. Results showed a 1.56 and 1.40 g/cm3 bulk density and a 41.0 and 47.2% porosity, respectively. To assess water availability, saturated soil samples were drained via a hanging water column simulating field capacity conditions to estimate VWC (28.3 and 34.4%, respectively). Results show relatively high water retention capacity at the surface layer due to elevated clay content, as determined by textural analysis. This is associated with low permeability, which may restrict water availability and root growth for plants and provide challenges during cultivation of new collections. Recommendations include application of organic material, such as compost, which may serve to increase water and nutrient availability to plants through vulnerable developmental stages.