Course Introduction

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Welcome video from Dr. Vimala Nair, one of the course instructors, giving an overview and objectives of the course.


Module 1: Welcome, Course Overview, and Conventional Techniques for Evaluating Phosphorus (P) Release from Soils


Lecture 1: Welcome and course overview

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Introduces the instructors and outlines the course structure, objectives, and the content for each module.



Lecture 2: Sampling soils for P risk assessment

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Describes tools and techniques for sampling upland and wetland soils and how to prepare a soil for analysis.



Lecture 3: Conventional techniques for evaluating phosphorus release from soils - water soluble P and soil test P

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Explains water soluble phosphorus (WSP) as an important parameter in P-related issues, the extraction procedure for WSP, and soil testing for phosphorus, including choice of extractant and the extraction procedure for Mehlich 1-P, and compares two procedures for phosphorus analysis.

  • Chrysostome, M., V.D. Nair, W.G. Harris, and R.D. Rhue. 2007. Minimizing confounding factors in phosphorus leaching assessment for dairy-and poultry-manure-amended soils. Commun. Soil Sci. Pl. Anal. 38:975 – 987.
  • Fixen, P.E., and J.H. Grove. 1990. Testing soils for phosphorus. p. 141–180. In R.L. Westerman (ed.) Soil testing and plant analysis, 3rd ed. SSSA Book Series No. 3. Soil Sci. Soc. Am., Madison, WI.
  • Hooda P.S., A.R. Rendell, and A.C. Edwards. 2000. Relating soil phosphorus indices to potential phosphorus release to water. Journal of Environmental Quality 29: 1166 – 1171.
  • Kleinman, P., D. Sullivan, A. Wolf, R. Brandt, Z. Dou, H. Elliott, J. Kovar, A. Leytem, R. Maguire, P. Moore, L. Saporito, A. Sharpley, A. Shober, T. Sims, J. Toth, G. Toor, H. Zhang and T. Zhang. 2007. Selection of water-extractable phosphorus test for manures and biosolids as an indicator of runoff loss potential. Journal of Environmental Quality 36:1357 – 1367.
  • Kovar, J.L. and G M. Pierzynski (editors). 2009. Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters. Second Edition. Southern Cooperative Series Bulletin No. 408.
  • McDowell, R. W., and A. N. Sharpley. 2001. Soil phosphorus fractions in solution: influence of fertilizer and manure, filtration and method of determination. Chemosphere 45: 737 – 748.
  • Mehlich, A. 1953. Determination of P, Ca, Mg, K, Na, and NH4. Soil Testing Div. Publ. 1 – 53. North Carolina Dep. of Agric., Raleigh.
  • Mehlich, A. 1984. Mehlich 3 soil test extractant: A modification of Mehlich 2 extractant. Commun. in Soil Sci. Plant Anal. 15:1409 – 1416.
  • Mylavarapu, R., Obreza, T., Morgan, K, Hochmuth, G., Nair, V., and Wright, A. 2014. Extraction of soil nutrients using Mehlich-3 reagent for acid-mineral soils of Florida. SL407.
  • Sims (1998). Soil testing for phosphorus: Environmental uses and implications. SERA-IEG 17 Minimizing agricultural phosphorus losses for protection of water resource. ISBN:1-58161-389-X



Lecture 4: Oxalate-extractable P, iron-oxide strip P, and total P

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Shows the laboratory techniques for evaluating P dynamics in soils and sediments by determining P extracted from soils, including oxalate-extractable P, iron-oxide strip P, and total P in soil.

  • Andersen, J.M., 1976. An ignition method for determination of total phosphorus in lake sediments. Water Res. 10, 329 – 331.
  • Chardon, W.J., RG. Menon, and S.H. Chien. 1996. Iron oxide impregnated filter paper (Pi test): a review of its development and methodological research. Nutr. Cycl. Agroecosys. 46:41 – 51.
  • Klatt, J.G., A.P. Mallarino, J.A. Downing, J.A. Kopaska, and D.J. Wittry. 2003. Soil phosphorus, management practices, and their relationship to phosphorus delivery in the Iowa Clear Lake agricultural watershed. J. Environ. Qual. 32:2140 – 2149.
  • McKeague, J.A., Day, J.H., 1966. Dithionate and oxalate-extractable Fe and Al as aids in differentiating various classes of soils. Can. J. Soil Sci. 46, 13 – 22.
  • Mehlich, A. 1953. Determination of P, Ca, Mg, K, Na, and NH4. Soil Testing Div. Publ. 1 – 53. North Carolina Dep. of Agric., Raleigh.
  • Menon, R.G., L.L. Hammond, and H.A. Sissingh. 1989. Determination of plant-available phosphorus phosphorus by iron hydroxide-impregnated filter paper (Pi) soil test. Soil Sci. Soc. Am. J. 53:110 – 115.
  • USEPA, 1993. Determination of phosphorus by semi-automated colorimetry. Methods for Chemical Analysis of Water and Wastes. Method 365.1. J.W. O’Dell (ed.) USEPA Cincinnati, OH.



Lecture 5: Soil phosphorus fractionation procedures

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Explains why soil P fractionation procedures are performed and compares fractionation schemes and their modifications.

  • Nair, V.D., D.A. Graetz, and D.O. Dooley. 2003. Phosphorus release characteristics of manure and manure-impacted soils. J. Food, Agriculture and Environment 1:217 – 223.
  • 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.
  • Pettersson, K., and V. Istvanovics. 1988. Sediment phosphorus in Lake Balaton – Forms and mobility. Ergeb. Limnol. 30:43 – 49.
  • Reddy, K.R., Y. Wang, W.F. Debusk, M.M. Fosher, and S. Newman. 1998. Forms of soil phosphorus in selected hydrologic units of the Florida Everglades. Soil Sci. Soc. Am. J. 62:1134 –1147.

Next - Module 2: How Florida Soils Interact with Phosphorus