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PHOSPHORUS IN FLORIDA WATERSHEDS: SCIENCE AND APPLICATIONS

 

Module 5: Phosphorus Storage and Release from P-impacted Soils

 

Lecture 1: Long-term contribution of phosphorus from agricultural lands: “legacy” P

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Describes P loss from Spodosols, explains the relationship between SPSC and water quality, and examines various P-impacted soils in the Lake Okeechobee Basin, with emphasis on what happens to P after a dairy is abandoned, what soil factors should be considered for sustainable dairy farming, and the role of the SPSC as a tool to indicate the amount of P that can be added before the soil becomes an environmental risk.

  • References
    • Graetz, D.A., and V.D. Nair. 1995. Fate of phosphorus in Florida Spodosols contaminated with cattle manure. Ecol. Eng. 5:163-181.
    • Nair, V.D., W.G. Harris, and D. Chakraborty. 2010. An Indicator for Risk of Phosphorus Loss from Sandy Soils. SL 333. http://edis.ifas.ufl.edu/pdffiles/SS/SS53900.pdf
    • Nair, V.D. W.G. Harris, D. Chakraborty, and M. Chrysostome. 2010. Understanding Soil Phosphorus Storage Capacity. SL 336. http://edis.ifas.ufl.edu/pdffiles/SS/SS54100.pdf
    • Nair, V.D., D.A. Graetz, and K.M. Portier. 1995. Forms of phosphorus in soil profiles from dairies of South Florida. Soil Sci. Soc. Am. J. 59:1244-1249

 

 

Lecture 2: Inorganic vs organic sources of P

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Describes how different P sources affect P storage and release from impacted soils, which in turn affects water quality of nearby water bodies. Discusses the relationship between manure components and P release, including P source characteristics such as P solubility that must be accounted for when evaluating P loss risk during land application of organic amendments. Details examples of P losses from different P sources and the relationships between the amounts of P leached and WSP and TP concentrations.

  • References
    • Harris, W.G., V.D. Nair, R.D. Rhue, and D.A. Graetz. 2007. Deliverable 2. Progress report on source materials characterization and implications for effects. Site-specific determination of soil capacity to assimilate or release P applied as manure, fertilizer, compost, or biosolids. Report to FDACS. Contract number 0061873. Tallahassee, FL.
    • Nair, V.D. and W.G. Harris. 2011. Phosphorus Sources and Risk Potential: Organic and Inorganic Fertilizers. SL 358. http://edis.ifas.ufl.edu/pdffiles/SS/SS55900.pdf
    • Rew, T.J., D.A. Graetz, M.S. Josan, V.D. Nair, and W.G. Harris. 2007. Phosphorus Mobility from Organic and Inorganic Soil Amendments: Rainfall Simulation Studies. ASA/CSSA/SSSA 2007 International Annual Meetings. CD Rom Publication.

 

 

Lecture 3: Reduction of soil P loss through amendment additions

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Discusses how to reduce P loss from soils though addition of amendments, with a focus on water treatment residues (WTRs) and biochar amendments.

 

 

Lecture 4: Natural and anthropogenic sources of P

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Examines differences in P loss risk from natural and anthropogenic sources of P (e.g., dairies or inorganically-fertilized soils), paying particular attention to some of the other components of the P source.

 

 

Lecture 5: Risk assessment of wetland soils

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Discusses phosphorus storage and release from P-impacted wetland soils and describes conventional risk assessment techniques and the use of SPSC for wetland soils.

Next - Module 6: Other Applications of the PSR and SPSC Concepts