Wednesday, November 15, 2006 - 1:15 PM

Manure Phosphorus Reactivity from Phytase Fed Swine in Manitoba Soils.

O. Stephen Abioye, Oluwole Akinremi, Martin Nyachoti, and Don Flaten. Univ of Manitoba, 362 Ellis Bldg, Winnipeg, MB R3T 2N2, Canada

            Manipulation of animal diets can reduce manure phosphorus (P) in areas where animal production is intensified. Solubility of swine manure P in soils amended with phytase will provide information on what changes occur in manure P with time. Manure samples were collected from 28 growing pigs fed randomly with seven dietary treatments at different levels of phytase. The seven treatments were: A positive control (NRC) that contains P at NRC (1998) recommendations, a negative control (RED)  containing 0.1 percentage units reduction (about 33%) in available P from 1998 NRC recommendations, RED + PHY1 (RED plus 500U of phytase / kg of diet), RED + PHY2 (RED plus 1000U of phytase / kg of diet), a double negative control with no added inorganic P (DNC), DNC + PHY3 (with 2000U of phytase / kg of diet), and DNC + 4000U of phytase / kg of diet). Manure (feces+urine) from 4 replicates of each treatment were mixed to form a composite and the total P determined. This manure was added to four Manitoba soils to provide total P of 75 kg P ha-1. The soils were incubated in four replicates at field capacity water content for 1, 4, 16 wks at 200C and then extracted using H2O, NaHCO3, Kelowna and Mehlich-3 solutions for extractable P. The results obtained will be presented and discussed.