Green Pi
The Phosphate Knowledge Center
Article Record
Title:Enhancing soil carbon sequestration on phosphate mine lands in florida by planting short-rotation bioenergy crops
Section:General -
Author:Stan D. Wullschleger, Steve A. Segrest, Donald L. Rockwood, Charles T. Garten Jr.
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Phosphate mines in northern and central Florida provide a valuable resource for the national and international production of agricultural fertilizers. However, separating phosphate-rich ore from the underlying sand and clay matrix creates large containment ponds or clay settling areas (CSA). The physical and chemical characteristics of CSAs make restoration a critical priority for post-mining activities. Therefore, to demonstrate the potential use of these areas for bioenergy crop production and carbon sequestration, a 50-ha demonstration planting consisting of Eucalyptus grandis, E. amplifolia, cottonwood, cypress, and slash pine hybrid trees was established on a CSA beginning in 2000 near Lakeland, Florida. Establishment costs may be as high as $1,250 per acre, including costs of site preparation and planting. Yield estimates for 2.5-year-old E. grandis planted in single rows varied from 10 to 16 dry tons of biomass per acre. In addition to providing a carbon-neutral option for mitigating rising CO2 in the atmosphere, an important opportunity exists for promoting soil carbon sequestration as a result of restoration. Our analysis, using a simple model that describes the soil carbon dynamics indicates the potential for long-term increases in soil carbon under bioenergy crop plantations. Science in support of these observations will require investigations aimed at (1) selecting tree species for site restoration, (2) identifying management practices to ensure plant survival and maximize growth, (3) improved characterization of below-ground biomass and determining inputs of roots to soil organic matter pools, (4) documenting the colonization of bulk and rhizosphere soils with micro-organisms beneficial to carbon and nitrogen cycling, and (5) quantifying changes in soil carbon and nitrogen stocks over time.

Submited to Green Pi:2010-05-20 By admin
Modified on Green Pi:2013-03-28 By farzi