2008 Joint Annual Meeting (5-9 Oct. 2008): Phosphorus Fractionation in Managed and Natural Wetlands in Northern California.
Start | Author Index

775-12 Phosphorus Fractionation in Managed and Natural Wetlands in Northern California.



Wednesday, 8 October 2008
George R. Brown Convention Center, Exhibit Hall E
Matthew D. Ruark, Bruce Linquist and Chris van Kessel, Plant Sciences, University of California-Davis, One Shields Ave., Davis, CA 95616
Phosphorus (P) cycling and availability in managed and natural wetlands in the Sacramento Valley have both agronomic and environmental implications.  Quantifying progressively extracted P fractions provides insight into how agricultural management has altered P cycling in this region, how much P may be available for rice uptake during the growing season, and the potential for P losses to surface waterways.  The objective of this study was to compare contents of P fractions in soils among conventional rice systems, organic rice fields, and natural wetlands in the Sacramento Valley.  Ninety-three soils were collected over three years (2005, 2006, and 2007).  The P from each soil was fractionated into exchangeable P (sodium bicarbonate extraction), iron-bound P (sodium hydroxide extraction), calcium-bound P (dilute hydrochloric acid extraction) and residual P (sulfuric acid digestion).  Results indicate that geographic location within the Sacramento Valley (and subsequent soil properties) had a large effect on P fraction contents.  Soils in or near the Sacramento River flood bypass (southern valley) had the highest total P contents.  Soils in the western valley had much greater calcium-bound P compared to soils from the eastern valley.  There did not appear to be major differences between managed wetland soils and agricultural soils with respect to total P content.  Overall, these results provide a clear indication that P fertilizer recommendations need to be developed separately for each geographic area within the Sacramento Valley. 
See more of: Wetland Soils (includes Graduate Student Competition) (Posters)
See more of: S10 Wetland Soils