INFERRING OZONE DEPOSITION ON AGRICULTURAL SURFACES - AN APPLICATION TO HERBACEOUS AND TREE CANOPIES

A combined gradient transfer-inferential technique was tested to evalu ate ozone deposition on two agricultural systems, an herbaceous crop ( soybean) and a fruit tree orchard (peach). The measurements were perfo rmed at a rural site in northern Italy's Po valley, where summer ozone concentration values often register levels exceeding the national hea lth standard because of the presence of industrial facilities. Canopy resistance, which is mainly the result of stomatal regulation, proved in both cases the most important component of total resistance to dry deposition. The fruit tree canopy evinced a more marked propensity for ozone uptake. The average deposition velocity on soybean was 0.43 cm s(-1), and a mean value about three-fold higher was calculated on peac h.