Abstract
Aluminum (Al) applied to land in the form of water treatment residuals (Al‐WTR) can reduce soluble soil phosphorus (P). Two experiments (145 and 148 d) using 36 grazing Holstein steers were conducted to determine effects of Al‐WTR applications to pasture on mineral status of cattle and bahiagrass (Paspalum notatum). Four treatments were with and without Al‐WTR and P‐free mineral supplementation. Total pasture application of Al‐WTR over 2 years was 75.8 metric tons dry weight/ha. There were few treatment effects on weight gains and mineral tissue concentrations. Forage mineral concentrations were generally unaffected by treatment but were affected (P < 0.05) by collection dates. Most forage samples were deficient in sodium (Na), copper (Cu), selenium (Se), and cobalt (Co) and at various collections deficient in calcium (Ca), P, iron (Fe), and zinc (Zn). Applications of Al‐WTR are effective in reducing P contamination without affecting forage or cattle mineral concentrations.
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