Browsing by Subject "manure"
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Item Chemical fractionation and solubility of phosphorus in dairy manure-amended soils as a predictor of phosphorus concentration in runoff(Texas A&M University, 2007-04-25) Harstad, Laura ElizabethNutrient over-loading in many dairy manure-amended soils in the dairy producing areas of Texas has led to environmental problems as such eutrophication of local surface water bodies. One of the nutrients contributing to eutrophication problems is phosphorus (P). This project focused on fractionation and solubility of selected P forms in an effort to determine a relationship with P found in runoff from dairy manureamend soils. Ten soils (5 calcareous, 5 noncalcareous) were collected from the dairy producing areas of Texas. Triplicate soil samples were analyzed for 0-5 cm and 5-15 cm depths. An acid-base extraction method was used to determine total P (TP), inorganic P, and organic P. Sequential extractions were used to determine the loosely-bound P, iron (Fe) phosphates, aluminum (Al) phosphates, reductant soluble P, occluded apatite P, and calcium (Ca) phosphates for calcareous and noncalcareous samples. The ammonium oxalate method was used to determine extractable Fe, Al, and silicon (Si). Potassium chloride extraction was used to determine soluble Ca, Al, Fe, Mg, and P. A weak NaOH extract was used to determined the amount of bioavalible P. Dissolved P in runoff events and soil pH were collected in a previous study. Calcareous and noncalcareous soils displayed varying concentrations of P indifferent fractions and with separate comparisons, stronger relationships could be achieved. It was also determined that KCl soluble Mg could be used as a predictor for dissolved and total P in runoff for calcareous soils (r2??????s ranging from 0.865 to 0.928 and 0.801 to 0.886, respectively). Ammonium oxalate extractable Al also yielded high correlations in calcareous soils for dissolved and total P in runoff (r2 ranging from 0.798 to 0.991 and 0.766 to 0.973, respectively). In noncalareous soils, pH resulted in a less correlated relationship with dissolved P (r2 = 0.600). This study shows that there are simple and effective ways of predicting dissolved and total P in runoff to improve best management practice recommendations for manure-amended soils.Item Occurrence and Fate of Escherichia Coli from Non-Point Sources in Cedar Creek Watershed, Texas(2011-08-08) Padia, ReemaFecal contamination is the pollution caused by the microorganisms residing in the intestine of warm blooded animals and humans. Bacteria are the prime cause of contamination of surface waters in the US. The transport of microorganisms into waterways can have detrimental effects on water quality and human health especially if the pathogenic strains are ingested. E. coli is used as an indicator of fecal contamination. Detection of these bacteria in a water body above set limits poses a potential health hazard. Various sources contribute to the bacterial contamination of a water body. The sources need to be identified and quantified for their E. coli content to measure bacteria loads in the waterbody accurately. In many cases, in-situ re-growth is also believed to be a considerable source of E. coli. Also re-growth of E. coli in landscapes due to favorable environmental conditions (e.g., rainfall after dry weather conditions) is one of the major phenomena affecting E. coli concentration in streams. Thus the environmental factors like temperature and soil moisture that influence transport, persistence, re-growth, and survival of E. coli in landscapes were studied. The objective of this study was to identify, characterize and quantify E. coli loads from feces of four different animals and monitor survival, growth and re-growth at four different temperatures and moisture contents over a period of seven days. Findings of this research will aid in Watershed Protection Plan (WPP) development and Total Maximum Daily Load (TMDL) development to address impairment from point and non-point source pollution of E. coli. Wildlife and range cattle manure samples responsible for fecal contamination of Cedar Creek were identified and four fecal sources out of those were quantified for the E. coli concentrations. No significant difference was found upon comparing the E. coli concentration for each species between the genders. Sub-adult cattle demonstrated significantly higher E. coli concentrations than adult cattle. Growth and die-off rates were measured at different temperatures (0degreesC, 10degreesC, 25degreesC, and 50degreesC) and moisture conditions (1%, 25% 56.5% and 83%). E. coli concentrations in cattle and raccoons feces showed highest survivability and growth at 20degreesC out of all the temperatures studied. There was no survival of E. coli from either species at 50degreesC after 24 h. E. coli in cattle and raccoons samples exhibited greater growth at lower, nearly aerobic soil moisture content (25%) for all days compared to nearly anaerobic soil moisture content (83%).Item Phosphorus reduction in dairy effluent through flocculation and precipitation(Texas A&M University, 2005-02-17) Bragg, Amanda LeannPhosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.