AN INEXPENSIVE LABORATORY AND FIELD CHAMBER FOR MANURE VOLATILE GAS FLUX ANALYSIS

摘要

Understanding the interactions between the environment and emissions from livestock manure is essential in developing management practices intended to minimize negative environmental consequences. However, protocols and equipment necessary to investigate these interactions at the laboratory or field-scale are cumbersome and can be expensive. An inexpensive dynamic flux chamber (cost < USD400 per unit) was designed to measure gaseous emissions from cattle manure in laboratory and field experiments. The hemispherical stainless steel chamber (emission surface = 0.08 m{sup}2) was constructed with an internal gas mixing fan. A port was attached to the chamber top, which facilitated the collection of headspace gas samples for greenhouse gases and volatile organic compounds (VOC) by solid-phase microextraction (SPME). The chamber was tested to evaluate flow characteristics and was found to perform very similarly to a continuous-flow stirred reactor. As such, concentrations measured at the sampling port were indicative of concentrations anywhere in the headspace. In laboratory and field applications, the inexpensive dynamic flux chamber was easy to use and required little operator input to quickly obtain multiple samples to measure the relative emissions of greenhouse gases, ammonia (NH{sub}3), and VOC from multiple sites in cattle feedlot pens.