Fig nbsp xA Periodograms of
3.4. EMD analysis of GSK461364 EC1:5
The variations in soil EC1:5 along each transect were separated into six IMFs and the residue (Fig. 4). The IMFs were similar for major axes (P1 and A1) and for minor axes (P2 and A2) but were different between major and minor axes (Fig. 4). IMF1 (Fig. 4) represented the smallest scales of variations (peaked at 200–500 m) (Fig. 5b) and contributed a large amount of variance (ranging 16–20%) to the total variance in soil EC1:5 (Table 2). However, none of the soil properties were significantly correlated with IMF1 (Fig. 6) indicating weak controls on soil salinity from those properties at the scale of 200–500 m. These may therefore be attributed to random variations in soil salinity, as well as to variations that might arise from interpolation and resampling. These small scale variations may also be caused by different land use types and uneven irrigation ditches (Shi et al., 2002).
Fig. 4. IMFs of soil EC1:5 along P1, P2, A1, and A2, with soil EC1:5 plotted on the top.Figure optionsDownload full-size imageDownload as PowerPoint slide