Report - ICP Forests

58 3. Intensive Monitoring
3.3.3. Results
3.3.3.1 BC/Al and pH
Overall variation of BC/Al and pH in all measurements for four different soil depth classes is
displayed in Figures 3.3.3.1-1 and 3.3.3.1-2. In all soil depths overall variation was large and
differences between lysimeter types were small. Mean pH slightly increased with sampling
depth, for BC/Al no such trend can be detected. BC/Al ratio and pH positively correlated for all
available measurements (r s = 0,55; p = 0,01).
Figure 3.3.3.1-1: Overall variation within all single measurements of pH in different sampling depths; Boxes
represent first and third quartile and median; whiskers represent 5 and 95% of all data; dots and stars
represent outliers and extremes. N = 4 739 for zero tension lysimetry; N = 14 836 for tension lysimetry.
Figure 3.3.3.1-2: Overall variation within all single measurements of BC/Al ratio in different sampling depths; note
logarithmic scaling of Y-axis. Boxes represent first and third quartile and median; whiskers represent 5 and
95% of all data; dots and stars represent outliers and extremes. N = 7 704 for zero tension lysimetry; N =
24 233 for tension lysimetry.