Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/25/2001
Publication Date: 4/25/2001
Citation: Compston, S.R., West, C.P., Sauer, T.J., Parkin, T.B. 2001. Nitrous oxide emissions from poultry litter-amended bermudagrass pastures. American Forage and Grassland Conference Proceedings. 10:126-130. Interpretive Summary: Many atmospheric scientists believe that increasing amounts of certain gases in the atmosphere are changing the earth's temperature. One of these "greenhouse gases" is nitrous oxide. Nitrous oxide can be formed from reactions in soil, especially if the soil has received nitrogen fertilizer. This experiment involved measuring nitrous oxide production in a bermudagrass pasture in northwestern Arkansas that had turkey litter (manure with bedding material) applied as a source of nitrogen. The measurements showed that turkey litter application increases nitrous oxide production significantly. Several soil properties that affect nitrous oxide production like nitrogen concentration in the soil, soil pH, soil water content, and soil temperature were measured but did not clearly explain the trends in nitrous oxide production. It is likely that no single factor was more important than another but a combination of factors influenced the amount of nitrous oxide produced. This research is important for growers because it shows that adding too much nitrogen fertilizer can lead to increased production of nitrous oxide with possible negative effects on the global climate.
Technical Abstract: Nitrous oxide (N2O) is a greenhouse gas that is produced naturally in the soil during nitrification and denitrification. Production is often accelerated on agricultural soils because nitrogen (N) fertilizers act as a source of N for N2O production. Data are lacking on the magnitude of N2O losses from pasture soils receiving poultry litter as N fertilizer. Research was conducted on a commercial turkey/beef farm to determine the effects of poultry litter and interseeded rye (Secale cereale L.) on N2O emission from a bermudagrass (Cynodon dactylon [L.] Pers.) pasture. Nitrous oxide was collected in vented soil covers to quantify losses. We measured nitrate, ammonium, pH, water-filled pore space, and temperature to characterize soil conditions during sampling and to explore their relationships with N2O production. Rye had no effect on N2O production (P = 0.88). Poultry litter fertilization increased (P = 0.02) N2O production from 61 to 102 ug/m**2/hr. Rates of nitrous oxide emission did not correlate well with field measurements. The strongest correlation was found with temperature during spring N2O sampling (r = 0.45, P = 0.05). Poor correlation was likely due to several environmental factors combining to affect N2O production.