title: Impact of manure phosphorus fractions on phosphorus loss from manured soils after incubation.
abstract: The risk of P loss from manured soils is more related to P fractions than total P concentration in manure. This study examined the impact of manure P fractions on P losses from liquid swine manure- (LSM), solid cattle manure- (SCM), and monoammonium phosphate- (MAP) treated soils. Manure or fertilizer was applied at 50 mg P kg soil, mixed, and incubated at 20°C for 6 wk to simulate the interaction between applied P and soil when P is applied well in advance of a high risk period for runoff. Phosphorus fractions in manure were determined using the modified Hedley fractionation scheme. We used simulated rainfall (75 mm h⁻¹ for 1 h) to quantify P losses in runoff from two soils (sand and clay loam). The proportion of total labile P (total P in water+NaHCO fractions) in manure was significantly greater in LSM (70%) than SCM (44%). Mean dissolved reactive P (DRP) load in runoff over 60 min was greatest from MAP-treated soil (18.1 mg tray⁻¹), followed by LSM- (14.0 mg tray⁻¹) and SCM- (11.0 mg tray⁻¹) treated soils, all of which were greater than mean DRP load from the check (5.2 mg tray⁻¹). Total labile P (water+NaHCO) in manure was a more accurate predictor of runoff DRP loads than water extractable P, alone, for these two soils. Therefore, NaHCO extraction of manure P may be a useful tool for managing the risk of manure P runoff losses when manure is applied outside a high risk period for runoff loss.
authors.affiliation: Environmental Studies Program, Univ. of Winnipeg, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Kumaragamage
authors.forename: D N
authors.initials: DN
authors.lastname: Flaten
authors.forename: O O
authors.initials: OO
authors.lastname: Akinremi
authors.forename: C A
authors.initials: CA
authors.lastname: Sawka
authors.forename: D
authors.initials: D
authors.lastname: Ige
authors.forename: F
authors.initials: F
authors.lastname: Zvomuya
mesh_terms: D000818:Animals; D002417:Cattle; D005308:Fertilizers; D008372:Manure / Q000032:analysis*; D010758:Phosphorus / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D013997:Time Factors; D014872:Water Movements
chemical_list: D005308:Fertilizers; D008372:Manure; D012987:Soil; D010758:Phosphorus