Fig. 5: Speciation of sulfur (S) in NaOH and ultrapure water extracts of Kohala soils along the rainfall gradient. | Nature Communications

Fig. 5: Speciation of sulfur (S) in NaOH and ultrapure water extracts of Kohala soils along the rainfall gradient.

From: Understanding soil selenium accumulation and bioavailability through size resolved and elemental characterization of soil extracts

Fig. 5

Panel a provides the distribution of S among the five identified size exclusion chromatography (SEC) fractions in NaOH extracts of soil horizons A and B. Panel b shows the proportion of NaOH-extractable organic S (sum of SEC fractions F2-F4) in all analyzed soils (n = 25) as a function of soil organic carbon (SOC) concentrations. Panel c provides the distribution of S among the five identified SEC fractions in ultrapure water extracts of soil horizons A and B. Panel d shows the proportion of water-soluble organic S (sum of SEC fractions F2–F4) in all analyzed soils (n = 25) as a function of dissolved organic carbon (DOC) concentrations. Correspondence between soil horizons and soil depths is given in Supplementary Table 1. For all presented data, the error bars represent standard deviations, which consider i) the standard deviation obtained during the SEC peak deconvolution; ii) the standard deviation of soil S concentrations that were determined in triplicate (for data in panels b and d); and iii) the standard deviation resulting from averaging the measured data for soil depth samples to obtain the data for soil A and B horizons (for data in panels a and c).

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