Skip to main content
Skip to main content
Give      University of Florida

PHOSPHORUS IN FLORIDA WATERSHEDS: SCIENCE AND APPLICATIONS

 

Module 4: Recent Developments in Techniques for Evaluating Phosphorus Release from Soils

 

Lecture 1: Degree of P saturation & the P saturation ratio: Theory and calculations

View on YouTube

Describes why the degree of P saturation ratio (DPS) is used and how to calculate it, including the extractants that can be used for DPS calculations. Explains the P saturation ratio (PSR), the preferred extractants, and molar calculations. Describes the change point concept and the difference between soil test phosphorus (STP) and PSR.

  • References
    • Beck et al., 2004. Soil Sci. Soc. Am. J. 68:1762−1771.
    • Breeusma, A and S. Silva. 1992. Phosphorus fertilization and environmental effects in The Netherlands and the Po region (Italy). Rep. 57. Winard Staring Center, Wageningen, The Netherlands.
    • Freese, D., R. Lookman, R. Merckx, and W.H. van Riemsdijk. 1995. New method for assessment of long-term phosphate desorption from soils. Soil Sci. Soc. Am. J. 59:1295–1300.
    • Khiari, L., L.E. Parent, A. Pellerin, A.R.A. Alimi, C. Tremblay, R.R. Simard, and J. Fortin. 2000. An agri-environmental phosphorus saturation index for acid coarse-textured soils. J. Environ. Qual. excessive losses of P from agricultural land continue to 29:1561–1567
    • Maguire, R.O., and J.T. Sims. 2002. Soil testing to predict phosphorus leaching. J. Environ. Qual. 31:1601−1609.
    • Nair, V.D., and D.A. Graetz. 2002. Phosphorus saturation in Spodosols impacted by manure. J. Environ. Qual. 31:1279-1285.
    • Nair, V.D., K.M. Portier, D.A. Graetz, and M.L. Walker. 2004. An environmental threshold for degree of phosphorus saturation in sandy soils. J. Environ. Qual. 33:107–113.
    • Paulter, M.C., and J.T. Sims. 2000. Relationships between soil test phosphorus, soluble phosphorus, and phosphorus saturation in Delaware soils. Soil Sci. Soc. Am. J. 64:765-733.
    • Sims, J.T., R.O. Maguire, A.B. Leytem, K.L. Gartley, and M.C. Pautler. 2002. Evaluation of Mehlich 3 as an agri-environmental soil phosphorus test for the mid-Atlantic United States of America. Soil Sci. Soc. Am. J. 66:2016−2032.

 

 

Lecture 2: Degree of P saturation and the P saturation ratio: Examples from literature

View on YouTube

Gives examples from the literature of reported change points, including those for Florida soils, for the spodic horizon and for wetland soils, and summarizes threshold PSR values from the literature for soils globally and in Florida.

  • References
    • Breeusma, A and S. Silva. 1992. Phosphorus fertilization and environmental effects in The Netherlands and the Po region (Italy). Rep. 57. Winard Staring Center, Wageningen, The Netherlands.
    • Casson, J.P., Bennett, D.R., Nolan, S.C., Olson, B.M., Ontkean G.R., and J.L. Little. 2006. Degree of phosphorus saturation thresholds in Alberta soils. 40 pp. In Alberta Soil Phosphorus Limits Project. Volume 3: Soil sampling, manure application, and sorption characteristics. Alberta Agriculture, Food and Rural Development, Lethbridge, Alberta, Canada.
    • Chakraborty, D., V.D. Nair, M. Chrysostome, and W.G. Harris. 2011. Soil phosphorus storage capacity in manure-impacted Alaquods: Implications for water table management. Agric. Ecosyst. Environ. 142: 167–175. 
    • Hooda, P.S., A.R. Rendell, A.C. Edwards, P.J.A. Withers, M.N. Aitken, and V.W. Truesdale. 2000. Relating soil phosphorus indices to potential phosphorus release to water. J. Environ. Qual. 29:1166-1171.
    • Indiati, R., and Sequi, P. 2004. Phosphorus intensity-quantity relationships in soils highly contrasting in phosphorus adsorption properties. Comm. Soil Sci. Plant Anal. 35:131-143.
    • Laboski, C.A.M., and J.A. Lamb. 2004. Impact of manure application on soil phosphorus sorption characteristics and subsequent water quality implications. Soil Science 169: 440-448.
    • Maguire, R.O., and J.T. Sims. 2002. Soil testing to predict phosphorus leaching. J. Environ. Qual. 31:1601−1609.
    • Nair, V.D. 2014. Soil phosphorus saturation ratio for risk assessment in land use systems. Front. Environ. Sci. 2:6. doi:10.3389/fenvs.2014.00006
    • Nair, V. D., M. W. Clark, and K.R. Reddy. 2015. Evaluation of legacy phosphorus storage and release from wetland soils. J. Environ. Qual. 44: 1956 – 1964. doi:10.2134/jeq2015.03.0154.
    • Nair, V.D., K.M. Portier, D.A. Graetz, and M.L. Walker. 2004. An environmental threshold for degree of phosphorus saturation in sandy soils. J. Environ. Qual. 33:107–113.
    • Nair, V.D., and K.R. Reddy. 2013.  Phosphorus sorption and desorption in wetland soils.  pp 667 – 678. In: DeLaune, R., Reddy, K.R., Richardson, C.J., and Megonigal, P. (ed). Methods on biogeochemistry of wetlands. Soil Science Society of America Publication.
    • Paulter, M.C., and J.T. Sims. 2000. Relationships between soil test phosphorus, soluble phosphorus, and phosphorus saturation in Delaware soils. Soil Sci. Soc. Am. J. 64:765-733.Pote, D.H., T.C. Daniel, D.J. Nichols, A.N. Sharpley, P.A., Moore, Jr., D.M. Miller, and D.R. Edwards. 1999. Relationship between phosphorus levels in three Ultisols and phosphorus concentrations in runoff. J. Environ. Qual. 28:170-175.
    • Sharpley. 1998. Personal Communication.
    • Sims, J.T., A.C. Edwards, O.F. Schoumans, and R.R. Simard. 2000. Integrating soil phosphorus testing into environmentally based agricultural management practices.  J. Environ. Qual. 29:60−71.
    • Vadas, P.A., Kleinman, P.J.A., Sharpley, A.N., and Turner, B.L. 2005. Relating soil phosphorus to dissolved phosphorus in runoff: A single extraction coefficient for water quality modeling. J. Environ. Qual. 34:572-580.

 

 

Lecture 3: The P saturation ratio (PSR) and isotherm parameters

View on YouTube

Reviews isotherm models and their components, including equilibrium P concentration and Smax under aerobic and anaerobic conditions, and relates isotherm parameters to soil test data.

 

 

Lecture 4: Soil phosphorus storage capacity (SPSC)

View on YouTube

Describes the soil P storage capacity (SPSC), a new indicator for evaluating P release from soils, how it is used, how to calculate it for A and E horizons, for the Bh horizon and for the spodic horizon, discusses the relationship between SPSC and WSP for wetland soils, and explains the application of PSR and SPSC in risk assessment of soils.

 

 

Lecture 5: Relating recently developed techniques (PSR & SPSC) to existing data

View on YouTube

Reviews the QPT procedure and the relationship between QPT and Mehlich 1-P and PSR, discusses the effects of biochar application to a low-P retentive soil and a high-P retentive soil using SPSC, and describes how to use the recently developed technique to explain the Florida-P index, with suggested modifications to the Florida-P index based on the SPSC.

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