Fig. 3: Abiotic and biotic factors controlling the proportion of surface soil free light and mineral-associated carbon fractions across biomes. | Communications Earth & Environment

Fig. 3: Abiotic and biotic factors controlling the proportion of surface soil free light and mineral-associated carbon fractions across biomes.

From: Ecosystem productivity has a stronger influence than soil age on surface soil carbon storage across global biomes

Fig. 3

a includes a structural equation model (SEM) of significant relationships among variables (p < 0.05) determining the proportion of carbon (C) fractions. Red and blue arrows represent positive and negative relationships, respectively, and their thicknesses the strength of the relationship. Numbers adjacent to arrows are standardized path coefficients, indicative of the sign and strength of the relationships among the variables. b shows the standardized total (direct + indirect) effects (STE) of abiotic and biotic predictors on the proportion of C fractions. MAT mean annual temperature, MAP mean annual precipitation, NPP (NDVI) plant productivity. Information on the direct effects for other SEM arrows can be found in Supplementary Table 2. *p < 0.05. Proportion of C fraction i (%) = C fraction i content × 100/sum of all C fraction contents. See text and Supplementary Data 1 for information on the chronosequences.

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