title: Predicting Phosphorus Release from Anaerobic, Alkaline, Flooded Soils.
abstract: Anaerobic conditions induced by prolonged flooding often lead to an enhanced release of phosphorus (P) to floodwater; however, this effect is not consistent across soils. This study aimed to develop an index to predict P release potential from alkaline soils under simulated flooded conditions. Twelve unamended or manure-amended surface soils from Manitoba were analyzed for basic soil properties, Olsen P (Ols-P), Mehlich-3 extractable total P (M3P), Mehlich-3 extractable molybdate-reactive P (M3P), water extractable P (WEP), soil P fractions, single-point P sorption capacity (P), and Mehlich-3 extractable Ca (M3Ca), and Mg (M3Mg). Degree of P saturation (DPS) was calculated using Ols-P, M3P or M3P as the intensity factor, and an estimated adsorption maximum based on either P or M3Ca + M3Mg as the capacity factor. To develop the model, we used the previously reported floodwater dissolved reactive P (DRP) concentration changes during 8 wk of flooding for the same unamended and manured soils. Relative changes in floodwater DRP concentration (DRP), calculated as the ratio of maximum to initial DRP concentration, ranged from 2 to 15 across ten of the soils, but were ≤1.5 in the two soils with the greatest clay content. Partial least squares analysis indicated that DPS3 calculated using M3P as the intensity factor and (2 × P) + M3P as the capacity factor with clay percentage can effectively predict DRP ( = 0.74). Results suggest that P release from a soil to floodwater may be predicted using simple and easily measurable soil properties measured before flooding, but validation with more soils is needed.
authors.forename: Geethani
authors.initials: G
authors.lastname: Amarawansha
authors.forename: Darshani
authors.initials: D
authors.lastname: Kumaragamage
authors.forename: Don
authors.initials: D
authors.lastname: Flaten
authors.forename: Francis
authors.initials: F
authors.lastname: Zvomuya
authors.forename: Mario
authors.initials: M
authors.lastname: Tenuta
mesh_terms: D000327:Adsorption; D055868:Floods; D008372:Manure; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*
chemical_list: D008372:Manure; D012987:Soil; D010758:Phosphorus