Figure 2. Physicochemical characterization of soils used for Jatropha cultivation with or without torrefied biomass.

The moisture contents of saturated absorption (A) and compression mechanical stress under wet soil conditions (B). T₂ relaxation time of binding (C) and free water contents (D). The error bars show the standard error of the mean and the p value for comparison of the control with each sample calculated using Welch’s t test. ^*p < 0.05, ^†p < 0.01, and ^‡p < 0.005.