IMPROVING CHEMICAL, PHYSICAL, AND BIOLOGICAL PROPERTIES OF DEGRADED SANDY SOILS FOR ENVIRONMENTALLY SUSTAINABLE PRODUCTION
Location: Coastal Plain Soil, Water and Plant Conservation Research
Project Number: 6657-12130-002-00
Start Date: May 02, 2011
End Date: May 01, 2015
1. Develop specifically designed biochar or biochar mixtures that amend sandy SE coastal soils to increase aggregation, improve nutrient retention, sequester organic carbon, improve microbial characteristics, and decrease overall soil strength.
1a. Evaluate designer biochars and biochar blends impact on soil quality in laboratory incubations.
2. Determine relationships between cover crop selection, crop residue addition/removal, C loss pathways, and C sequestration to develop management practices that increase profile soil organic C (SOC) contents and maintain/improve soil microbial populations related to plant productivity.
2a. Determine the effects of sandy coastal soils and their management such as harvest frequency and N fertilizer rates on the following: a) switchgrass yields, b) improvements of in-profile SOC, c) C sequestration, d) switchgrass thermal bioenergy value, and e) nutrient removal with harvested biomass.
2b. Determine amount of residue that can be removed from a Coastal Plain soil while still maintaining crop productivity.
2c. Assess management practices that increase SOC contents in long-term tillage experiments.
The current method to improve degraded soils would be incorporation of crop residues which do not persist. To improve soils and their productive potential, there is a need to develop better management systems and more recalcitrant forms of soil organic C (SOC), such as biochar (a charcoal-like byproduct made during pyrolysis of organic feedstocks). First, biochars that have been designed (produced under specific conditions) and characterized will be catalogued and matched to the needs of these soils – to improve fertility, increase water holding capacities, and reduce root penetration resistance. Designed biochars and/or biochar blends will be lab tested in soils for effectiveness as recalcitrant SOC amendments. Second, impacts of alternative management and crops on SOC levels will be studied in field experiments with residue addition/removal at the surface and residue addition at root depths. In one case, cover crops will replace removed residues. Technologies resulting from these lines of research will improve soil physical, chemical, and microbial properties for enhanced soil quality, water retention, and crop/bioenergy productivity. These improvements help meet administration goals of enhanced food security, sequestered C, and reduced greenhouse gas (GHG) emissions. The immediate beneficiaries are Coastal Plain agribusinesses and farmers. The ultimate beneficiaries will be individuals and families who will be provided with sufficient food and clean water. More effective soil and crop management will enable agriculture and other sectors of society to share water/soil resources, maintain environmental quality, and improve food production.