Changes in Soil Properties and Enzymatic Activities Following Manure Applications to a Rangeland

Manure amendments to rangelands may alter soil functions related to nutrient recycling. We investigated the influence of grazing and cattle manure on soil carbon, nitrogen, Mehlich 3 phosphorus, and activities of alkaline phosphatase and dehydrogenase. Fertilizer treatments (unamended, manure, or urea + potassium dihydrogen phosphate [KH2PO4] fertilizer) were imposed under grazed and nongrazed conditions in a short-grass native rangeland. Manure was applied at rates of ∼ 125 kg N ha−1 and ∼ 42 kg P ha−1, and urea + KH2PO4 was applied at 75 kg N ha−1 and 20 kg P ha−1, respectively. Total aboveground biomass and soil samples at 4 depths (0–200 mm) were collected throughout 2 growing seasons. A controlled environment study also evaluated fertilizer source effects on enzymatic activities at 5 P rates (0–120 mg·kg−1 P as manure or urea + KH2PO4). Amendments significantly (P