A simple, controllable, non-point source of gaseous ammonia, for use in field experiments

摘要

A type of controllable non-point source of gaseous NH_3 has been developed, which is simpler, more reliable and more versatile in use than earlier types of source. The source is based on a suitable length of a suitable type of permeable plastic tubing, to which pure NH_3 gas is supplied at a suitable pressure. Once steady state is achieved, the emission rate of NH_3 from the tubing equals the permeation rate through tubing wall: the rate is continuously monitored via the rate of weight loss from the cylinder supplying the NH_3 gas, mounted on a suitable recording electronic balance.