Showing papers by "George A. O'Connor published in 2000"
TL;DR: Results were similar to those observed in the previous year, with reapplication of biosolids having no cumulative effects in most cases, although the soil P levels of some treatments did appear higher in year two.
Abstract: Effects of applications of exceptional quality biosolids (sludge) to bahiagrass (Paspalum notatum) pastures in successive years, or residual effects of applications the previous year, on macromineral crude protein (CP) and in vitro digestibility (IVOMD) status of forage and soils in north Florida were studied in relation to beef cattle nutrient requirements. Thirty 0.8 ha pastures were assigned one of 9 treatments representing two sources of biosolids. Biosolids (Baltimore and Tampa) were applied at an “agronomic rate” (X) and 2X. Four of the treatments represented residual applications of the Baltimore and Tampa biosolids which had been applied to pastures as in the previous year. The control plot received NH4NO3. Forages were analyzed for calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na), crude protein (CP), and in vitro organic matter digestibility (IVOMD), and soils were analyzed for Mehlichl extractable Ca, P, Mg, and K. Single (agronomic or twice this) applications, or reappli...
48 citations
TL;DR: In this article, the effects of applying exceptional quality biosolids (sludge) to bahiagrass (Paspalum notatum) pastures in successive years, or residual effects of applications the previous year, on micromineral status of forage and soils in north Florida were studied in relation to beef cattle requirements.
Abstract: Effects of applications of exceptional quality biosolids (sludge) to bahiagrass (Paspalum notatum) pastures in successive years, or residual effects of applications the previous year, on micromineral status of forage and soils in north Florida were studied in relation to beef cattle requirements. Thirty 0.8 ha pastures were assigned one of 9 treatments representing three sources of biosolids. Two biosolids (Baltimore and Tampa) were applied at an “agronomic rate” (X) and 2X. Four of the treatments represented residual applications of Baltimore and Tampa biosolids which had been applied to pastures as in the previous year. The control plot received NH4NO3. Forages were analyzed for copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), molybdenum (Mo), cobalt (Co) and selenium (Se), and soils were analyzed for Mehlich-l extractable Cu, Mn, and Zn. Forage Co, Cu, and Se concentrations were low and deficient in relation to beef cattle requirements for most of the grazing season. Forages receiving Tampa treatment...
47 citations
TL;DR: The decline of animal Cu status (liver and plasma) reflects the low Cu status of bahiagrass and the possibility of high forage S interfering with Cu metabolism, which had a tendency to decline in plasma and for all biosolids treatments declined in liver.
Abstract: Angus x Hereford heifers (n = 50) were randomly assigned to bahiagrass pastures treated with biosolids varying in mineral content and evaluated for mineral status, with special attention to Cu. Biosolids and NH4NO3 were all applied at the rate of either 179 kg N/ha (X) or twice this (2X). Fertilizer was applied to .81-ha pastures for the following treatments: 1) Baltimore biosolids (1X = 179 kg N/ha); 2) Baltimore biosolids (2X = 358 kg N/ha); 3) Tampa biosolids (1X = 179 kg N/ha); 4) Tampa biosolids (2X = 358 kg N/ha); or 5) control NH4NO3 (1X = 179 kg N/ha) applied at two times. Pastures were divided into five blocks with each treatment represented once in each block. Copper loads varied from 8.8 to 42.2 kg/ha, and Mo loads varied from .27 to 1.11 kg/ha. Heifers (two per pasture) grazed their assigned pastures exclusively for 176 d. Liver biopsies were taken from all animals at d 1, 99, and 176, and blood samples on d 1, 50, 99, 135, and 176. Liver and plasma were analyzed for selected mineral contents, and blood was analyzed for hemoglobin and hematocrit. Experimental animals were generally low in mineral status when assigned to pastures and deficient in Se and P. By d 50, plasma Ca, Mg, Se, P, and Zn were adequate for all treatments. Plasma Cu declined (P < .03) for all treatments from d 50 to 176. Plasma Cu reflected depleted liver Cu storage, with the two Tampa and highest Baltimore treatment means lower in plasma Cu than the control at 176 d. Liver Fe concentrations were adequate for all treatments, and Mo concentrations (< 2.18 mg/kg) did not approach levels indicative of toxicity. Liver Cu declined (P < .05) with time for all treatments. By d 99, animals receiving the two Baltimore treatments and the lowest Tampa application rate had lower (P < .05) liver Cu than the control, and all treatments were lower at 176 d. The decline of animal Cu status (liver and plasma) reflects the low Cu status of bahiagrass and the possibility of high forage S (.30 to .47%) interfering with Cu metabolism. Forage Mo was low but was slightly higher in biosolids-treated pastures. High levels of biosolids applications to bahiagrass pastures were not detrimental to mineral status except Cu, which had a tendency to decline in plasma and for all biosolids treatments declined in liver.
18 citations