Table 1. Description of the five long-term fumigated study sites in Watsonville, CA, USA * Means followed by different letters in a column are significantly different by Tukey’s test at p < 0.05. Ca, Calcium; K, potassium; Mg, magnesium; Na, sodium; S, sulfur; dissolved organic carbon, DOC; TN, total nitrogen; TC, total carbon. Table 2. pH, macronutrients, dissolved organic carbon (DOC), total nitrogen (TN), and total carbon in fumigated and non-fumigated sites at the 0-5 cm depth. Figure 1. Total phospholipid fatty acid (PLFA) for fumigated and non-fumigated sites at (A) 0-5 cm; (B) 5-15 cm; and (C) 15-30 cm depths. Different letters indicate significant differences (p < 0.05). Error bars indicate standard error. Soil samples were collected from 15, 26, 33, 39a, 39b yaf sites as well as non-fumigated (NF-15, NF-33 and NF-39) sites. Figure 1. Total phospholipid fatty acid (PLFA) for fumigated and non-fumigated sites at (A) 0-5 cm; depth, total PLFA in NF-33 site was higher than in fumigated 26, 39a, 39b and non-fumigated 39 sites whereas at 15-30 cm depth, total microbial biomass in non-fumigated sites (33 and 15) was higher ir comparison to 26 yaf site (Figure 1B,C). Values are least square means. Values for each effect within a column with the same letter were not significantly different (p < 0.05). Standard errors are in parentheses. Table 3. PLFA biomarker proportions at the 0-5 cm depth. Values are least square means. Values for each effect within a column with the same letter were not significantly different (p < 0.05). Standard errors are in parentheses. Table 4. PLFA biomarker proportions at the 5-15 cm depth. Figure 2. (A) AMF, (B) fungal, (C) gram positive, (D) gram negative, (E) actinomycetes, and (F) eukaryotic PLFA proportions at the 0-5 cm depth. Different letters indicate significant differences (p < 0.05). Error bars indicate standard error. Samples were collected from 15, 26, 33, 39a and 39b yaf sites. Values are least square means. Values for each effect within a column with the same letter were not significantly different (p < 0.05). Standard errors are in parentheses. Table 5. PLFA biomarker proportions at the 15-30 cm depth. Figure 4. (A) AMF, (B) fungal, (C) gram positive, (D) gram negative, (E) actinomycetes, and (F) eukaryotic PLFA proportions at the 15-30 cm depth. Different letters indicate significant differences (p < 0.05). Error bars indicate standard error. Samples were collected from 15, 26, 33, 39a and 39b yaf sites. Figure 5. Canonical multivariate analysis of variance of phospholipid fatty acid biomarkers for 0-5 cm, 5-15 and 15-30 cm depths. Vectors represent standardized canonical coefficients and indicate the relative contribution of each biomarker group to each canonical variate. Soil samples were collected from 15, 26, 33, 39a, 39b yaf sites as well as non-fumigated (NF-15, NF-33 and NF-39) sites. Figure 5. Canonical multivariate analysis of variance of phospholipid fatty acid biomarkers for 0-5 cm, t+ CV, Canonical variate. Table 6. Structure matrix (pooled with canonical structure) and function at group centroid for 0-5, 5-15, and 15-30 cm soil depths. Table 7. Changes in the ratio of saturated /monounsaturated PLFAs and cyclopropyl PLFAs to their precursors for fumigated and non-fumigated sites at 0-5, 5-15, and 15-30 cm depths. Different letters indicate significant differences (p < 0.05). Soil samples were collected from 15, 26, 33, 39a, 39b yaf sites as well as non-fumigated (NF-15, NF-33 and NF-39) sites.
