Spatial and Temporal Variability of Phosphorus Retention in a Riparian Forest Soil

Abstract

Riparian zones remove P from surface runoff and can act as filters of nonpoint source (NPS) P pollution for surface waters. Riparian forest soils were investigated in spring and fall for their capacity to retain PO4~--P. Samples (300 on each date) were taken from a soil drainage catena from moderately well (MWD), somewhat poorly (SPD), and poorly drained (PD) soil in May and November of to examine spatial and temporal variability of P retention and its relationship to soil properties. The equilibrium P concentration at zero sorption (EPC0) was determined for each sampling point (lower EPC0, = higher P retention capacity). Mean (coefficient of variation, CV) EPC0 values were 3.8 (0.49) mg -t in M ay and no P sorption was apparent in November for SPD soil, 1.0 (1.34) and 1.5 (1.03) P L-1 in May and November, respectively for MWD soil, and 0. 5 (1.87) and 1.3 (1.13) mg -~, respectively for PD s oil. The EPC0 was significantly and positively correlated to organic matter (OM) for all drainage classes on both dates. Low EPC0 values--high P retention capacity--in MWD and PD soil corresponded with high Feo~ and AIox values. For SPD soil, .high mean EPC0 corresponded with low mean Feox and Alox values. The relationship between EPC0and Feox and AIox was described by a hyperbolic function for MWD and PD soil, but not for SPD soil. The EPC0 did not exhibit spatial structure at the sampling scale used for any of the drainage classes, even though Feox, Aloe, and OM content showed spatial structure. B WoodwardHall, Univ. of Rhode Island, Kingston, RI 02881.

Variabilité spatiale des réserves de nutriments dans les humus et les sols d’un massif forestier (Fougères, France)

“…A lower stock variability by level was observed in the Alocrisols-Neoluvisols compared with the Colluviosols-Fluviosols (Fig. 3) and confirmed the high spatial variability of soil properties in these locations [12,23,30,41].…”

“…3). Lyons et al [30] noted that soil properties, such as organic matter, soil moisture, pH, amorphous Fe and Al are known to influence phosphorus retention. Stevenson [40] specified that organic matter may coat Fe and Al oxides, thus blocking potential sorption sites and decreasing phosphorus adsorption.…”

Phosphorus release from coastal sediments: Impacts of the oxidation-reduction potential and sulfide

“…In particular, oxidation-reduction potential (ORP) may be an especially crucial factor controlling the release of P to the overlying water from sediments. In this regard, P-sediment adsorption experiments may be useful in examining the ORP-dependent ability of sediment to either remove or release P to the overlying water (Lyons et al, 1998;Pan et al, 2002).…”

Impact of Suspended Inorganic Particles on Phosphorus Cycling in the Yellow River (China)

“…Equilibrium phosphorus concentration (EPC 0 ), a parameter obtained from phosphate-sediment adsorption experiments, has been used to provide quantitative information on whether sediments remove or release P to the overlying water, 9,10 to calculate the P flux between sediment and the overlying waters, 10 and to estimate the exposure history of sediment to anthropogenic inputs of P. 11 The nature and history of the particulate matter is a crucial factor influencing P cycling. Most of the particulate matter in the Yellow River comes from soil erosion from the Loess Plateau.…”