Comparison of gas use efficiency and treatment uniformity in a forest ecosystem exposed to elevated [CO] using pure and prediluted free-air CO enrichment technology

摘要

A direct comparison of treatment uniformity and CO use of pure and prediluted free-air CO enrichment (FACE) systems was conducted in a forest ecosystem. A vertical release pure CO fumigation system was superimposed on an existing prediluted CO fumigation system and operated on alternate days. The FACE system using prediluted CO fumigation technology exhibited less temporal and spatial variability than the pure CO fumigation system. The pure CO fumigation system tended to over-fumigate the upwind portions of the plot and used 25% more CO than the prediluted CO fumigation system. The increased CO use by the pure CO system was exacerbated at low wind speeds. It is not clear if this phenomenon will also be observed in plots with smaller diameters and low-stature vegetation.