Biochar for a Sustainable Environment

electtronic supplementary material

Biochar for a Sustainable Environment

Interactive effects of biochar and polyacrylamide on decomposition of maize rhizodeposits: Implications from 14C labeling and microbial metabolic quotient

Yasser Mahmoud Awad1,4• Johanna Pausch2•Yong Sik Ok1 •Yakov Kuzyakov2,3,5

Received: 24 August 2015 / Accepted: 4 October 2016

© Springer-Verlag Berlin Heidelberg 2016

Responsible editor: Yu Luo

1Korea Biochar Research Center & School of Natural Resource and Environmental Sciences, Kangwon National University, Chuncheon 24341, Korea

2Department of Soil Science of Temperate Ecosystems, University of Göttingen, 37077 Göttingen, Germany

3Department of Agricultural Soil Science, University of Göttingen, 37077 Göttingen, Germany

4Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt

5Institute of Environmental Sciences, Kazan Federal University, 420049Kazan, Russia

Yasser Mahmoud Awad

Yong Sik Ok

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Table S1 Estimated CO2 efflux rates (µg C days-1 g-1 soil) driven from the decomposition of conditioners and maize rhizodeposits in soil

Incubation time (days)
Treatments / 2 / 4 / 8 / 13 / 18 / 25 / 32 / 46
Without rhizodeposits
BC† / 28.20 / ± / 8.38‡ / 0.00 / ± / 3.14 / 41.16 / ± / 37.38 / 13.22 / ± / 13.82 / -6.00 / ± / 13.28 / -2.02 / ± / 5.55 / 0.86 / ± / 2.97 / -5.18 / ± / 3.62
PAM / -4.04 / ± / 10.65 / 7.69 / ± / 5.44 / 6.52 / ± / 24.90 / -0.002 / ± / 6.24 / -2.40 / ± / 8.53 / -4.34 / ± / 2.89 / -6.88 / ± / 2.60 / -4.17 / ± / 4.26
BC+PAM / 36.26 / ± / 10.66 / 3.85 / ± / 4.97 / -0.50 / ± / 6.73 / -17.62 / ± / 3.87 / -33.60 / ± / 8.32 / -13.29 / ± / 2.85 / -2.00 / ± / 2.90 / -6.04 / ± / 8.98
With rhizodeposits
2 days after 14C labeling
BC / 39.03 / ± / 2.05 / -5.89 / ± / 8.08 / 0.51 / ± / 11.95 / -4.49 / ± / 18.31 / -1.22 / ± / 17.92 / -5.01 / ± / 11.59 / -3.21 / ± / 3.28 / -0.15 / ± / 3.69
PAM / -10.27 / ± / 2.05 / -3.92 / ± / 8.17 / -35.83 / ± / 6.11 / -6.53 / ± / 7.78 / -6.53 / ± / 10.70 / 2.36 / ± / 5.38 / -6.43 / ± / 1.75 / 8.22 / ± / 4.55
BC+PAM / 45.18 / ± / 4.11 / -7.85 / ± / 4.53 / -30.72 / ± / 22.19 / -11.23 / ± / 9.09 / -11.23 / ± / 6.05 / -2.65 / ± / 2.28 / -14.02 / ± / 4.89 / 4.69 / ± / 5.76
4 days after 14C labeling
BC / 28.89 / ± / 5.33 / 1.97 / ± / 6.73 / -3.60 / ± / 12.94 / 2.87 / ± / 14.52 / 9.02 / ± / 19.47 / 6.81 / ± / 6.76 / 7.33 / ± / 1.94 / -5.45 / ± / 1.79
PAM / -22.69 / ± / 8.51 / -9.85 / ± / 4.96 / 28.28 / ± / 23.82 / 18.87 / ± / 15.13 / 18.87 / ± / 16.57 / 2.96 / ± / 6.80 / -4.99 / ± / 4.19 / 3.98 / ± / 4.57
BC+PAM / 22.69 / ± / 8.50 / -3.95 / ± / 5.09 / 13.88 / ± / 32.13 / 9.43 / ± / 15.21 / 9.43 / ± / 7.47 / 2.07 / ± / 1.96 / -1.47 / ± / 3.26 / -5.16 / ± / 4.04
8 days after 14C labeling
BC / 27.16 / ± / 13.24 / 11.12 / ± / 4.78 / -18.85 / ± / 5.20 / -7.33 / ± / 7.51 / -0.38 / ± / 11.06 / -0.28 / ± / 2.66 / 0.28 / ± / 2.64 / -6.65 / ± / 4.16
PAM / 25.23 / ± / 15.95 / 42.61 / ± / 8.21 / -35.28 / ± / 15.35 / -13.49 / ± / 10.67 / -13.49 / ± / 12.14 / -9.18 / ± / 2.74 / -17.37 / ± / 5.72 / -9.69 / ± / 3.25
BC+PAM / 34.91 / ± / 6.72 / 27.78 / ± / 8.22 / -0.48 / ± / 3.65 / 13.11 / ± / 3.59 / 13.11 / ± / 6.72 / 4.17 / ± / 3.19 / -8.82 / ± / 6.32 / -13.02 / ± / 2.76
16 days after 14C labeling
BC / 54.44 / ± / 5.51 / 3.71 / ± / 7.11 / -25.68 / ± / 19.60 / -11.98 / ± / 11.94 / -3.86 / ± / 14.28 / 0.00 / ± / 3.35 / 2.76 / ± / 3.57 / 17.08 / ± / 5.95
PAM / 11.69 / ± / 9.79 / 13.01 / ± / 3.56 / -43.60 / ± / 19.16 / -10.05 / ± / 15.31 / -10.05 / ± / 24.02 / -2.23 / ± / 9.48 / -14.93 / ± / 5.86 / 7.09 / ± / 3.04
BC+PAM / -75.85 / ± / 4.90 / 18.56 / ± / 7.11 / -59.11 / ± / 33.03 / -9.28 / ± / 16.62 / -9.28 / ± / 12.65 / 6.41 / ± / 3.45 / -7.74 / ± / 2.51 / 7.64 / ± / 8.48

†Control: untreated soil, BC: 10 tons ha-1 biochar, PAM: 80 kg ha-1 polyacrylamide

‡the "±" values in each column are standard errors (n=4)

Table S2 Cumulative 14CO2 efflux (% of input 14C) from decomposition of maize exudates in soils treated with conditioners

Incubation time (days)
Treatments / 2 / 4 / 8 / 13 / 18 / 25 / 32 / 46
2 days after 14C labeling
Control† / 8.28 / ef‡ / 12.55 / de / 18.53 / ab / 22.83 / a / 25.68 / a / 28.21 / a / 29.96 / a / 32.14 / a
BC / 7.87 / fg / 11.33 / efg / 16.00 / cdef / 19.49 / abcd / 21.71 / abcd / 23.72 / abc / 25.11 / abcd / 27.10 / abc
PAM / 7.20 / gh / 10.68 / gh / 15.11 / efg / 18.61 / abcd / 20.88 / bcd / 23.04 / bc / 24.44 / bcd / 26.43 / bc
BC+PAM / 7.59 / fgh / 11.07 / fg / 15.55 / edf / 19.05 / abcd / 21.29 / bcd / 23.30 / bc / 24.71 / bcd / 26.67 / bc
4 days after 14C labeling
Control / 6.92 / hi / 9.61 / hi / 12.81 / ghi / 15.22 / bcd / 16.66 / ef / 17.94 / de / 18.81 / efg / 20.09 / edf
BC / 7.33 / gh / 10.26 / gh / 13.88 / fgh / 16.60 / abcd / 18.31 / def / 19.81 / cde / 20.83 / defg / 22.29 / cdef
PAM / 5.81 / j / 8.20 / j / 11.04 / i / 13.21 / d / 14.56 / f / 15.79 / e / 16.65 / g / 17.94 / f
BC+PAM / 6.10 / ji / 8.73 / ji / 11.84 / hi / 14.23 / cd / 15.75 / f / 17.12 / de / 17.88 / fg / 19.26 / ef
8 days after 14C labeling
Control / 10.58 / ab / 14.18 / ab / 18.07 / abc / 20.98 / abc / 22.81 / abc / 24.56 / ab / 25.78 / abc / 27.52 / abc
BC / 11.02 / a / 14.74 / a / 18.96 / a / 22.17 / ab / 24.17 / ab / 26.03 / ab / 27.41 / ab / 29.32 / ab
PAM / 10.19 / ab / 14.04 / abc / 18.12 / abc / 21.22 / abc / 23.21 / abc / 25.08 / ab / 26.37 / abc / 28.20 / ab
BC+PAM / 10.00 / bc / 13.59 / abcd / 17.73 / abcd / 15.42 / bcd / 22.96 / abc / 24.90 / ab / 26.21 / abc / 28.02 / ab
16 days after 14C labeling
Control / 9.97 / bcd / 13.41 / bcd / 16.91 / abcde / 19.46 / abcd / 21.12 / bcd / 22.65 / bc / 23.49 / bcde / 25.11 / bcd
BC / 9.89 / bcd / 13.35 / bcd / 17.05 / abcde / 19.78 / abcd / 21.68 / bcd / 23.46 / bc / 24.25 / bcd / 26.09 / bc
PAM / 9.08 / de / 12.31 / def / 15.70 / cdef / 18.27 / abcd / 19.95 / cde / 21.54 / bcd / 22.50 / cdef / 24.05 / bcde
BC+PAM / 9.24 / cd / 12.76 / cd / 16.47 / bcde / 19.06 / abcd / 21.02 / bcd / 22.84 / bc / 24.08 / bcd / 25.89 / bc

†Control: untreated soil, BC: 10 tons ha-1 biochar, PAM: 80 kg ha-1 polyacrylamide

‡the different letters in each column indicate significant differences at P <0.05

Table S3 Multifactor ANOVA for the effects of rhizodeposits, amendments (soil conditioners) and time on the tested variables

Source / DF* / Sum of squares / Mean square / F ratio / P > F / Source / DF / Sum of squares / Mean square / F ratio / P > F
CO2 efflux / µg C day-1 g-1 soil / Microbial biomass C / mg C kg-1
Rhizodeposits / R-1 = 4† / 54843.89 / 13710.97 / 13.84 / <0.0001 / Rhizodeposits / R-1 = 4 / 33429.74 / 8357.44 / 16.44 / <0.0001
Amendments / A-1 = 3 / 1675.20 / 558.40 / 0.56 / NS‡ / Amendments / A-1 = 3 / 1813.16 / 604.39 / 1.19 / NS
Time / T-1 = 7 / 111653.27 / 15950.47 / 16.09 / <0.0001 / Time / ST-1 = 1# / 1189.26 / 1189.26 / 2.34 / NS
Total / 14 / 168172.36 / 12012.31 / 12.12 / <0.0001 / Total / 8 / 36432.17 / 4554.02 / 8.96 / <0.0001
14CO2 efflux / % of the input 14C day-1 / qCO2 / mg CO2-C h−1 g biomass C
Rhizodeposits / R-C-1 = 3 / 6.40 / 2.13 / 28.61 / <0.0001 / Rhizodeposits / R-1 = 4 / 572.80 / 143.20 / 6.00 / 0.0003
Amendments / A-1 = 3 / 0.55 / 0.18 / 2.48 / NS / Amendments / A-1 = 3 / 295.91 / 98.64 / 4.14 / 0.0092
Time / T-1 = 7 / 942.49 / 134.64 / 1806.95 / <0.0001 / Time / ST-1 = 1 / 28730.06 / 28730.06 / 1204.66 / <0.0001
Total / 13 / 949.45 / 73.03 / 980.15 / <0.0001 / Total / 8 / 29598.77 / 3699.85 / 155.14 / <0.0001
Cumulative CO2 / mg С g-1 / Microbial biomass N / mg N kg-1
Rhizodeposits / R-1 = 4 / 18.20 / 4.55 / 93.81 / <0.0001 / Rhizodeposits / R-1 = 4 / 2488.56 / 622.14 / 34.84 / <0.0001
Amendments / A-1 = 3 / 1.00 / 0.33 / 6.85 / 0.0002 / Amendments / A-1 = 3 / 27.91 / 9.30 / 0.52 / NS
Time / T-1 = 7 / 256.58 / 36.65 / 755.66 / <0.0001 / Time / ST-1 = 1 / 15.70 / 15.70 / 0.88 / NS
Total / 14 / 275.78 / 19.70 / 406.10 / <0.0001 / Total / 8 / 2532.18 / 316.52 / 17.72 / <0.0001
Cumulative 14CO2 / % of input 14C / Microbial biomass 14C / (% of 14C input)
Rhizodeposits / R-C-1 = 3 / 2979.23 / 993.08 / 310.75 / <0.0001 / Rhizodeposits / R-C-1 = 3 / 2238.74 / 746.25 / <0.0001
Amendments / A-1 = 3 / 286.02 / 95.34 / 29.83 / <0.0001 / Amendments / A-1 = 3 / 211.85 / 70.62 / 0.82 / NS
Time / T-1 = 7 / 15104.94 / 2157.85 / 675.22 / <0.0001 / Time / ST-1 = 1 / 151.12 / 151.12 / 1.76 / NS
Total / 13 / 18370.19 / 1413.09 / 442.18 / <0.0001 / Total / 7 / 2601.71 / 371.67 / 4.34 / 0.0003

*DF= degrees of freedom, †R = soil without/with 14C-labeled rhizodeposits of different age (2, 4, 8 and 16 days after 14C labeling), ‡NS = no significant difference, #ST = sampling time. Where R = 5, A = 4, IT = 8, T = 2 and C = control soil without rhizodeposits.

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Table S4 Generalized linear model (GLM) analysis for the effects of amendments, time and their interaction (amendments × time) on the tested variables

Source / DF* / Sum of squares / Mean square / F ratio / P > F / Source / DF / Sum of squares / Mean square / F ratio / P > F
CO2 efflux / µg C day-1 g-1 soil / Microbial biomass C / mg C kg-1
Amendments / A-1 = 19† / 62721.53 / 3301.13 / 31.79 / <0.0001 / Amendments / A-1 = 19 / 54801.66 / 2884.30 / 2.25 / 0.0092
Time / T-1 = 7 / 111653.27 / 15950.47 / 153.62 / <0.0001 / Time / ST-1 = 1 / 411.62 / 411.62 / 0.32 / NS‡
Amendments × Time / 133 / 563354.14 / 4235.75 / 40.79 / <0.0001 / Amendments × Time / 19 / 18758.61 / 987.30 / 0.77 / NS
Total / 159 / 737728.94 / 4639.80 / 44.69 / <0.0001 / Total / 39 / 73971.88 / 1896.71 / 1.48 / NS
14CO2 efflux / % of the input 14C day-1 / qCO2 / mg CO2-C h−1 g biomass C
Amendments / A-C-1 = 15 / 7.22 / 0.48 / 91.91 / <0.0001 / Amendments / A-1 = 19 / 884.26 / 46.54 / 17.72 / <0.0001
Time / T-1 = 7 / 942.49 / 134.64 / 25710.60 / <0.0001 / Time / ST-1 = 1 / 34266.84 / 34266.84 / 13043.50 / <0.0001
Amendments × Time / 105 / 34.83 / 0.33 / 63.34 / <0.0001 / Amendments × Time / 19 / 1559.61 / 82.08 / 31.25 / <0.0001
Total / 127 / 984.54 / 7.75 / 1480.34 / <0.0001 / Total / 39 / 36710.71 / 941.30 / 358.30 / <0.0001
Cumulative CO2 / mg С g-1 / Microbial biomass N / mg N kg-1
Amendments / A-1 = 19 / 23.30 / 1.23 / 26.26 / <0.0001 / Amendments / A-1 = 19 / 2447.39 / 128.81 / 5.70 / <0.0001
Time / T-1 = 7 / 256.58 / 36.65 / 784.95 / <0.0001 / Time / ST-1 = 1 / 16.27 / 16.27 / 0.72 / NS
Amendments × Time / 133 / 3.80 / 0.03 / 0.61 / 0.9996 / Amendments × Time / 19 / 1127.94 / 59.37 / 2.63 / 0.0023
Total / 159 / 283.68 / 1.78 / 38.21 / <0.0001 / Total / 39 / 3591.60 / 92.09 / 4.08 / <0.0001
Cumulative 14CO2 / % of input 14C / Microbial biomass 14C / (% of 14C input)
Amendments / A-C-1 = 15 / 3610.46 / 240.70 / 119.34 / <0.0001 / Amendments / A-C-1 = 15 / 3603.10 / 240.21 / 9.87 / <0.0001
Time / T-1 = 7 / 15104.94 / 2157.85 / 1069.90 / <0.0001 / Time / ST-1 = 1 / 151.12 / 151.12 / 6.21 / NS
Amendments × Time / 105 / 471.80 / 4.49 / 2.23 / <0.0001 / Amendments × Time / 15 / 6795.19 / 453.01 / 18.61 / <0.0001
Total / 127 / 19187.20 / 151.08 / 74.91 / <0.0001 / Total / 31 / 10549.41 / 340.30 / 13.98 / <0.0001
Percentage of 14C rhizodeposits of different age retained in soils (% of the 14C input)
Rhizodeposits / R-1 = 3 / 325.10 / 108.37 / 10.05 / 0.0006
Amendments / SA-1 = 3 / 185.45 / 61.82 / 5.73 / 0.0073
Rhizodeposits × Amendments / 9 / 451.04 / 50.12 / 4.65 / 0.0038
Total / 15 / 961.59 / 64.11 / 5.95 / 0.0005

*DF= degrees of freedom, †A = Amendments, C= soil without rhizodepositsbut amended with conditioners (control, BC, PAM and BC+PAM), R = soil with 14C-labeled rhizodeposits of different age, #ST = sampling time ‡NS = no significant difference. Where A = 20, R = 4, T = 8, ST = 2 and C = 4

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Figure captions

Fig. S1 CO2 efflux (mg C day-1 g-1 soil) from soil without and with 2-, 4-, 8-, and 16-day-aged rhizodeposits in response to the addition of 10 tons ha-1 of biochar (BC), 80 kg ha-1 of polyacrylamide (PAM), and their combination (BC+PAM), compared to the control soils (no conditioner) without/with rhizodeposits. Error bars represent the standard error of the mean (n = 4)

Fig.S2 The retention of rhizodeposits 14C in soil at 46-day incubation depending on their age in response to the treatments with 10 tons ha-1 BC, 80 kg ha-1 of PAM, and their combination (BC+PAM), compared to the control soil (no conditioner) with rhizodeposits.Bars with the same letters are not significantly different at p ≤ 0.05 (n = 4)

Fig.S3 Microbial metabolic quotient (qCO2), and microbial biomass carbon (MBC) and nitrogen (MBN) in the soil at 2 and 46 days of the incubation in response to the addition of 10 tons ha-1 of biochar (BC), 80 kg ha-1 of polyacrylamide (PAM), and their combination (BC + PAM), compared to the control soil (no conditioner) without rhizodeposits. Bars with the same letters are not significantly different at p ≤ 0.05 (n = 4)

Fig. S1

Fig. S2

Fig. S3

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