Urea Hydrolysis and Calcium Carbonate Precipitation in Gypsum-Amended Broiler Litter
| Autor: | Christopher D B Burt, Michael J. Rothrock, David E. Kissel, Miguel L. Cabrera |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Environmental Engineering
Urease Bicarbonate 010501 environmental sciences Management Monitoring Policy and Law 01 natural sciences Calcium Sulfate Calcium Carbonate chemistry.chemical_compound Animal science Animals Urea Ammonium Waste Management and Disposal reproductive and urinary physiology 0105 earth and related environmental sciences Water Science and Technology biology Hydrolysis Broiler 04 agricultural and veterinary sciences Ammonia volatilization from urea Pollution Manure Calcium carbonate chemistry 040103 agronomy & agriculture biology.protein Litter 0401 agriculture forestry and fisheries Chickens |
| Zdroj: | Journal of environmental quality. 47(1) |
| ISSN: | 0047-2425 |
| Popis: | Broiler () litter is subject to ammonia (NH) volatilization losses. Previous work has shown that the addition of gypsum to broiler litter can increase nitrogen mineralization and decrease NH losses due to a decrease in pH, but the mechanisms responsible for these effects are not well understood. Therefore, three laboratory studies were conducted to evaluate the effect of gypsum addition to broiler litter on (i) urease activity at three water contents, (ii) calcium carbonate precipitation, and (iii) pH. The addition of gypsum to broiler litter increased ammonium concentrations ( < 0.0033) and decreased litter pH by 0.43 to 0.49 pH units after 5 d ( < 0.0001); however, the rate of urea hydrolysis in treated litter only increased on Day 0 for broiler litter with low (0.29 g HO g) and high (0.69 g HO g) water contents, and on Day 3 for litter with medium (0.40 g HO g) water content ( < 0.05). Amending broiler litter with gypsum also caused an immediate decrease in litter pH (0.22 pH units) due to the precipitation of calcium carbonate (CaCO) from gypsum-derived calcium and litter bicarbonate. Furthermore, as urea was hydrolyzed, more urea-derived carbon precipitated as CaCO in gypsum-treated litter than in untreated litter ( < 0.001). These results indicate that amending broiler litter with gypsum favors the precipitation of CaCO, which buffers against increases in litter pH that are known to facilitate NH volatilization. |
| Databáze: | OpenAIRE |
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