Thrust Areas Ecosystem Water Institute Classification Level
Water, Land Use and Ecosystems Water and Climate Water and Society Water Resources Sustainability Springs Wetlands Watersheds Aquifers Lakes Coastal Zone  Water Institute Classification 1  Water Institute Classification 2  Water Institute Classification 3  Water Institute Classification 4

Wetland Soils Nutrient Index Development and Evaluation of “Safe” Soil Phosphorus Storage Capacity
Contract No:  73946
Goals and Objectives
To better manage legacy phosphorus (P) in the Lake Okeechobee Watershed, reliable techniques to predict P storage and release from its uplands, ditches, streams and wetlands must be developed. Soil test P (STP) procedures such as Mehlich 1-P fail to precisely indicate whether a given soil is capable of retaining additional P (P “sink”) as opposed to functioning as a P source that would pose an environmental risk. The P saturation ratio (PSR) is the molar ratio of sorbed P (P held by the soil) to the sum of likely sorption components (Fe and Al) in the soil. When related to some measure of releasable P in the soil (i.e. water soluble P), PSR can be used as an indicator of the “change point” at which a soil becomes a P source to the environment. This project intended to determine the threshold PSR (or change point) for wetland soils and sediments, ditches and streams using techniques developed for upland soils. In this approach, water soluble P (WSP) is regressed against PSR for soils with a wide range of P, Fe, and Al concentrations, and the change point determined statistically using a non-linear equation. As part of the exploratory process of obtaining a threshold PSR value, compiled archived data were used to evaluate the feasibility of using some of the data for change point determinations, with the objective of using soils with a good range of P, Fe, and Al values which may not easily be obtained if fresh soils were used.
Available Outputs

Title: Prediction of phosphorus release from wetland soils. Poster. INTECOL 9 Wetlands Conference. June 2012. Orlando, Florida.
Authors: Nair, V.D., M. W. Clark, and K. Reddy

Title: Wetland Soils Nutrient Index Development and Evaluation of “Safe” Soil Phosphorus Storage Capacity
Authors: Nair, V.D., M.W. Clark and K.R. Reddy

Title: Wetland soils nutrient index evaluation. ASA/CSSA/SSSA 2011 International Annual Meetings. CD Rom Publication.
Authors: Nair, V.D., M.W. Clark, and K.R. Reddy
Project Lead
Nair, Vimala D
Project Participants
Nair, Vimala D
Additional Participants
Mark Clark
Konda Ramesh Reddy
Level 1: WI Affiliated Faculty Project
Water, Land Use and Ecosystems
Grant Award Dates
6/19/2009 to 8/31/2010