In this study, to properly compare CO2 emissions from Amng and
Lmng soils (and their changes due to band position), measurements
occurred at noon within a
∼2 h interval, when air (and soil) temperature
are usually roughly stable. This has restricted the number
of positions to be monitored (×30 a treatment) and likely renders
not easy to extrapolate data on emissions at whole orchard
scale. However, despite this study was not design to extrapolate
data at orchard scale, preliminary measurements were done to
evaluate the variability of CO2 emission across the orchard comparing
emissions at various positions (×15) around a tree in 15
randomly distributed trees. Measurements were collected at noon
(11:00–13:30 h) in three consecutive clear days. The effect of tree
was not significant at P = 0.05 (n = 225, Tukey–Kramer test) possibly
because of the uniformity of soil and plant (La Scala et al., 2000; Xu
and Qi, 2001).