St Augustine, Trinidad and Tobago | bharrison4@ucmerced.edu

Dr. Gaius Eudoxie is a Senior Lecturer of Soil Science at the University of West Indies (St. Augustine Campus) with responsibility for teaching and research in soil physical and fertility management. He has over 20 years teaching and research experience in soil management. He has successfully supervised several graduate students researching various aspects of soil management, composting and agronomy. Dr. Eudoxie has consulted across the Caribbean on sustainable soil management, composting, crop nutrition, contaminant risk assessment and remediation, fcousing mainly on training and development. He has partcipated in numberous webinars as a panelist and guest speaker. Dr. Eudoxie is a vice-president of the Latin America and the Caribbean Regional Soil Partnership and former Co-chair of the Intergovernmental Working Group on Drought under the UNCCD. He serves are the science advisor to the Partnership Initiative for Sustainable Land management and co-coordinates IWRM capacity building in the Caribbean through Caribbean WaterNet. 

Session Code: A2

Track: Current Research (hosted by CREF)

Session Name: Biological Indicators, Biochar Co-composting, Increasing SOC

Session Time: Wednesday, Jan 25, 1:45 to 3:15 PM

Presentation Title: Increasing Soil Organic Carbon (SOC) of a Mined Ultisol through the Application of Stable Carbon

Presentation Description: Amending spent aggregate mining soils with organic carbon not only contributes to climate change mitigation and adaptation but also improves soil health, which is critical for ecological restoration. Coarse textured tropical soils present high organic carbon turnover rates which may limit the benefits from organic amendments unless applied at appropriate rates and in a form that minimizes losses. A pot trial was performed to compare the degradation of stable (compost) and unstable (brewers spent grain) carbon sources applied to a disturbed Ultisol. Amendments were applied at equivalent rates of 0, 50, 100, 200 and 400 t ha-1. Soil health properties were monitored at 7, 30 and 90 days post application. pH, EC, SOC, Soil basal Respiration (SBR), Available Nitrogen (AN) and Aggregate Stability (AS) all showed significant (p < 0.05) responses to the interaction between application rate and C type. Soil pH showed a significant (p<0.05) linear incraese with increasing rate of compost. The response for both amendmets occurred after 28 days of incubation. SOC increased with the application of both amendments with maximum contents at 28 days after incorporation. Both carbon sources resulted in a decraese in SOC ~ 50% after 90 days of incubation, irrespective of application rate. Soil biological activtiy peaked after 28 days and was significantly (p<0.05) higher for BSG at all application rates. However, aggregate stability was improved onl with the addition of 400 t ha-1 of compost. Compost applied at high rates provide the greastest improvement in soil quality in the short term.