Fig. 3
Discriminating factors in soil VOC profiles with or without soybean plants in the flowering period in the Koriyama field. A two-way orthogonal partial least squares-discriminant analysis (O2PLS-DA) score scatter plot (A) and loading column plot (B). The structure of Peak 19, pentanoic acid, 2,2,4-trimethyl-3-carboxyisopropyl, isobutyl ester (C). In (A), the yellow circle represents soil samples without cultivating soybean plants, while the purple square represents soil samples with soybean plants. Observations = 44, variables = 20, including two dummy variables. Significant, analysis of variance testing of cross-validated predictive residuals (CV-ANOVA), pCV < 0.05. t[1], the first X-score; to[1], the first orthogonal X-score; pq[1], X loading weight p and Y loading weight q combined into one vector.
