Plant and Soil Jaiswal et al.

Supplementary Material

GC/MS analysis of aqueous biochar extracts

Aqueous extracts of the biochars were prepared by shaking 1 g biochar in 10 ml deionized water (hereafter, water) in 15 ml polypropylene centrifuge tubes in the dark for 24 hours, followed by sedimentation and filtration of the liquid solution via membrane filters of 0.22-µm pore size (Durapore PVDF membrane, Millipore Corp., Carrigtwohill, Ireland). Aliquots (2 ml) of the extracts were lyophilized and the dried residue subjected to a two-stage derivatization procedure immediately prior to analysis by GC/MS following the methods detailed in Graber et al. (2014). The residue was first methoxyamininated to stabilize carbonyl moieties, and then functional groups with active hydrogens were silylized with N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). The derivatized extracts were analyzed by quadrupole GC/MS (Agilent Technologies, Santa Clara, California, USA) using electron impact ionization. Separation was achieved on a 30-m long, VF-5M, 0.25 µm film, capillary column (Varian Inc., Palo Alto, California, USA). Total ion chromatograms (TIC) were analyzed with freely available deconvolution software (Automated Mass Spectral Deconvolution and Identification System; AMDIS) at a minimum match probability of 75% and retention indices based on a series of alkanes. The deconvoluted mass spectra were compared with a specialty library for plant, animal and microorganism metabolites (Golm Metabolite Database) freely provided by the Max Planck Institute for Metabolic Plant Physiology (Golm, Germany) and to the NIST08 mass spectral library. Results given in Table 5, Supplementary Material.

Table 1 Analysis of variance (ANOVA) to determine the effect of interaction between pyrolysis temperature (HTT) and concentration of eucalyptus (EUC) and greenhouse pepper plant wastes (GHW) biochar on disease caused by R. solani in bean.

Source / EUC / GHW
AUMPCa
(%×days) / Disease severity (%)b / AUMPCa
(%×days) / Disease severity (%)b
ANOVA
Model / 0.0028* / <0.0001* / <0.0001* / <0.0001*
R2 / 0.3047 / 0.4687 / 0.4047 / 0.4075
P-value
Temperature (T) / 0.0870 / 0.2148 / 0.7078 / 0.1504
Concentration (C ) / 0.0078* / <0.0001* / 0.0015* / <0.0001*
T×C / 0.3666 / 0.0590 / 0.7327 / 0.2239

aArea under mortality progress curve

bValues were normalized by an arcsine square root transformation before analysis.

*Significant at α < 0.05

Table 2 Analysis of variance (ANOVA) to determine the effect of interaction between feedstocks and concentration of biochar on disease caused by R. solani in bean.

Source / AUMPCa (%×days) / Disease severity (%)b
ANOVA
Model / 0.0057* / 0.0006*
R2 / 0.2566 / 0.3233
P-value
Feedstock (F) / 0.8654 / 0.4740
Concentration (C ) / 0.0224* / 0.0244*
F×C / 0.0084* / 0.0005*

aArea under mortality progress curve

bValues were normalized by an arcsine square root transformation before analysis

*Significant at α < 0.05

Table 3 Analysis of variance (ANOVA) to determine the effect of interaction between R. solani inoculation (inoculated and non-inoculated), pyrolysis temperature (HTT) and concentration of eucalyptus (EUC) and greenhouse pepper plant wastes (GHW) biochar on growth parameters of bean.

Source / EUC / GHW
Plant height
(cm) / Shoot dry weight (g) / Plant height
(cm) / Shoot dry weight (g)
ANOVA
Model / <0.0001* / <0.0001* / <0.0001* / <0.0001*
R2 / 0.7297 / 0.7999 / 0.7108 / 0.6757
P-value
Rhizoctonia inoculation (I) / <0.0001* / <0.0001* / <0.0001* / <0.0001*
Temperature (T ) / 0.0636 / 0.1025 / 0.0002* / 0.0090*
Concentration (C ) / 0.5377 / 0.0362* / 0.0049* / 0.4418
I×T / 0.2140 / 0.5891 / 0.0003* / 0.0034*
I×C / 0.0820 / 0.0239* / 0.7185 / 0.0759
T×C / 0.8353 / 0.9835 / <0.0001* / <0.0001*
I×T×C / 0.8892 / 0.3383 / 0.0139* / 0.0864

*Significant at α < 0.05

Table 4 Analysis of variance (ANOVA) to determine the effect of pyrolysis temperature (HTT) and concentration of eucalyptus (EUC) biochar on growth parameters of bean (non-inoculated).

Source / EUC / GHW
Plant height
(cm) / Shoot dry weight (g) / Plant height
(cm) / Shoot dry weight (g)
ANOVA
Model / <0.0001* / <0.0001* / <0.0001* / <0.0001*
R2 / 0.8055 / 0.7967 / 0.8095 / 0.7057
P-value
Temperature (T ) / 0.0111* / 0.1570 / <0.0001* / <0.0001*
Concentration (C ) / 0.0574 / 0.0117* / 0.0068* / 0.5742
T×C / 0.8499 / 0.6069 / <0.0001* / <0.0001*

*Significant at α < 0.05

Table 5 Putative identifications by gas chromatograph/mass spectrometer (GC/MS) of compounds in aqueous extracts of eucalyptus woodchips (EUC) biochars produced at 350◦C (EUC-350) and 600◦C (EUC-600) and greenhouse pepper plant waste (GHW) biochars produced at 350◦C (GHW-350) and 600◦C (GHW-600).

Compound / Retention time / EUC-350 / EUC-600 / GHW-350 / GHW-600
2-Hydroxypropanoic acid / 18.379 / Y / Y / Y
Lactic acid / 18.396 / Y / Y / Y / Y
Hexanoic acid / 19.297 / Y / Y
Hydroxyacetic acid (glycolic acid) (alpha-hydroxy acid) / 19.542 / Y / Y / Y / Y
1,2-Butanediol / 22.163 / Y / Y
3-Hydroxypropanoic acid / 23.074 / Y
Heptanoic acid / 24.102 / Y / Y
4-Hydroxybutanoic acid / 26.660 / Y / Y
Benzoic acid / 26.920 / Y / Y / Y
Octanoic acid / 27.598 / Y
Glycerol / 27.898 / Y / Y / Y
Succinic acid / 29.189 / Y / Y / Y
3-Methylbenzoic acid / 29.333 / Y
2-Methylbutanedioic acid / 29.516 / Y / Y / Y
Glyceric acid / 29.654 / Y
2-Methylbenzoic acid / 30.216 / Y
Nonanoic acid / 30.554 / Y
Oxalic acid / 31.522 / Y
Glutaric acid / 31.831 / Y
Benzenepropanoic acid / 32.120 / Y
Sulfurous acid, 2-ethylhexyl isohexyl ester / 33.982 / Y
Decanoic acid / 33.208 / Y
Salicylic acid / 34.432 / Y
1,4,5-Pentatriol / 34.462 / Y
Pyroglutamic acid / 34.765 / Y / Y
2-Piperidinecarboxylic acid / 34.825 / Y
Erythronic acid / 35.297 / Y
Threonic acid / 35.299 / Y
4-Hydroxybenzoic acid / 35.887 / Y
3-hydroxybenzoic acid / 37.344 / Y
Methyl α-d-lyxofuranoside / 38.043 / Y / Y
D-Altro-2-Heptulose (sedoheptulose) / 38.307 / Y
1,6-Anhydro-beta-d-glucose / 38.520 / Y
1,6-Anhydroglucose / 38.986 / Y / Y / Y
Cyperaquinone / 39.205 / Y
4-Benzylimidazole-5-(1-propenoic acid), methyl ester / 39.274 / Y
Tetradecanoic acid / 42.248 / Y
Mannitol / 43.613 / Y
Silane, dimethyl(4-(2-phenylprop-2-yl)phenoxy)butoxy- / 43.748 / Y
Hexadecanoic acid / 46.035 / Y / Y / Y
Myo-Inositol / 46.618 / Y / Y
Octadecanoic acid / 49.573 / Y
Trehalose / 57.061 / Y
Melezitose / 57.130 / Y

References

Graber ER, Tsechansky L, Lew B, Cohen E (2014) Reducing capacity of water extracts of biochars and their solubilization of soil Mn and Fe. Eur J Soil Sci 65:162-172.

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