Solubility of Macrominerals from Tall Fescue Fertilized with Different Swine Manure Treatments and Harvested on Four Dates

摘要

Fertilization with animal manures provides numerous mineral nutrients to the desired crop. Our objective was to determine the impacts of fertilization with manure from different swine dietary or manure treatments on mineral solubility from tall fescue(Festuca arundinacea Schreb.) harvested at four growth stages. Manure from pigs fed a normal growing and finishing diet (NORM) or a diet with added phytase (0.03%; PHY) was collected. This manure was applied on March 14, 2003 to supply 113 Ib N/acre tothree of four experimental tall fescue pastures. The four pastures received either no swine manure (negative control; CONT), NORM, PHY, or PHY with the manure treated with aluminum chloride (0.75%) at application (PHY+AL). Dacron bags containing these forages were either rinsed directly or inserted in the rumen of five ruminally cannulated steers (1,208 Ib BW) to determine water solubility and ruminal mineral solubility. Water-soluble phosphorus (P), calcium (Ca), and magnesium (Mg), and ruminally-soluble P, Ca, Mg, and sulfur (S) trends varied across growth stages with respect to the different fertility treatments. In general, water solubility of P and Mg was high (> 70%), while that of S was intermediate (46 to 70%) and that of Ca was low (19 to 36%). Ruminal solubility of P, Mg, and S were high (> 75%) in most instances and that of Ca was greater than 50% in most instances. Therefore, fertilization with different swine manure treatments did not alter forage mineral solubility in a consistent manner, and ruminal solubility is not a limiting factor in fnrape mineral utilization.