Table 1 Physical, chemical and biological parameters of the constructed soil mixtures underlining different soil functions

From: Constructing (multi)functional soil using urban organic and sediment wastes

Substrate mixtures

Controls

Single biochar mixtures

Dual biochar mixtures

Subsoil

+ 4% mGWC

+ 2% mGWC + 2% GAC

+ 2% mGWC + 2% WW | 850

+ 2% mGWC + 2% WW | 540

+ 2% mGWC + 2% GW | 680

+ 2% mGWC + 1% WW | 850 + 1% GW | 680

+ 2% mGWC + 1% WW | 540 + 1% GW | 680

+ 2% mGWC + 1% WW | 850 + 1% WW | 540

Bulk density (g cm−3)

 Medium sand

1.31 ± 0.06

1.26 ± 0.02

1.22 ± 0.01

1.24 ± 0.07

1.20 ± 0.05

1.20 ± 0.07

1.19 ± 0.07 *

1.22 ± 0.03

1.22 ± 0.03

 Sandy clay loam

1.36 ± 0.01

1.23 ± 0.04 *

1.24 ± 0.01 *

1.25 ± 0.02

1.23 ± 0.01 *

1.23 ± 0.04 *

1.26 ± 0.03

1.22 ± 0.03

1.24 ± 0.06 *

SSA after dry mixing (m2 g−1)

 Medium sand

7.21 ± 0.12

6.81 ± 0.22

22.84 ± 9.11

9.16 ± 0.32

8.62 ± 0.63

6.71 ± 0.08

7.89 ± 0.08

7.49 ± 0.02

8.30 ± 0.65

 Sandy clay loam

8.23 ± 0.11

7.26 ± 0.12

25.31 ± 3.05

8.86 ± 0.43

7.34 ± 0.56

6.76 ± 0.31

8.07 ± 0.53

7.53 ± 0.35

7.88 ± 0.74

pH

 Medium sand

7.00 ± 0.02

7.16 ± 0.07

7.45 ± 0.05 *

7.39 ± 0.02 *

7.69 ± 0.15 *∆

8.22 ± 0.09 *∆†

7.30 ± 0.38 *

7.67 ± 0.03 *∆

7.36 ± 0.11 *

 Sandy clay loam

8.30 ± 0.10

8.31 ± 0.01

8.52 ± 0.01

8.45 ± 0.05

8.44 ± 0.03

8.94 ± 0.05 *∆†

8.75 ± 0.01 *∆

8.68 ± 0.03 *∆

8.45 ± 0.02

CEC (cmol•c kg−1)

 Medium sand

4.75 ± 0.89

8.54 ± 1.61 *

6 23 ± 0.72

6.63 ± 0.81 *∆

6.59 ± 0.87 *∆

6.52 ± 0.46 *∆

6.12 ± 0.47 ∆

6.33 ± 0.61

5.82 ± 1.11 ∆

 Sandy clay loam

9.320 ± 1.57

11.74 ± 0.65 *

10.25 ± 0.48

10.12 ± 0.51

10.01 ± 0.25 ∆

10.47 ± 0.55

10.21 ± 0.57

10.24 ± 0.52

10.21 ± 0.08

TN (mg g−1)

 Medium sand

0.24 ± 0.01

0.98 ± 0.17 *

0.61 ± 0.11 *

0.90 ± 0.20 *†§

0.86 ± 0.27 *†

1.22 ± 0.18 *†§

0.66 ± 0.10 *∆

1.00 ± 0.23 *

0.65 ± 0.10 *∆

 Sandy clay loam

0.79 ± 0.04

1.58 ± 0.13 *

1.18 ± 0.04 *

1.16 ± 0.07 *∆

1.23 ± 0.09 *∆

1.55 ± 0.16 *†

1.28 ± 0.05 *∆

1.39 ± 0.10 *

1.24 ± 0.08 *∆

C to N ratio

 Medium sand

10.2 ± 0.6

15.7 ± 0.4 *

40.9 ± 7.7 *

36.6 ± 2.7 *∆§

35.6 ± 3.0 *∆†

20.2 ± 0.8 *†§

24.3 ± 1 *∆†

28.1 ± 2.8 *∆†

36.5 ± 2.5 *∆

 Sandy clay loam

10.2 ± 2.7

17.1 ± 1 *

32.8 ± 3.6 *

26.5 ± 2.5 *∆†

27.1 ± 2.1 *∆†

16.4 ± 0.5 *†§

20.5 ± 1.2 *†

22.7 ± 3.4 *∆†

26.1 ± 3.4 *∆†

TOC (mg g−1)

 Medium sand

1.44 ± 0.15

14.66 ± 3.32 *

24.98 ± 8.28 *

32.77 ± 6.5 *∆§

31.25 ± 12.74 *∆

24.34 ± 4.81 *

15.86 ± 3.13 *

27.66 ± 9.23 *∆

24.04 ± 5.33 *

 Sandy clay loam

9.94 ± 0.73

26.19 ± 3.12 *

38.79 ± 2.25 *

30.99 ± 4.41 *

33.88 ± 2.57 *

29.96 ± 4.06 *†

27.04 ± 1.85 *†

35.02 ± 4.47 *

34.46 ± 3.23 *

CaCO3 (mg g−1)

 Medium sand

0

ng

ng

ng

ng

ng

ng

ng

ng

 Sandy clay loam

512 ± 18

447 ± 19

465 ± 20

451 ± 24

470 ± 22

500 ± 14

481 ± 9

460 ± 36

483 ± 34

Respired mgC-CO2 g−1 soil

 Medium sand

0.10 ± 0.01

0.27 ± 0.03 *

0.28 ± 0.04 *

0.29 ± 0.02 *

0.27 ± 0.03 *

0.38 ± 0.03 *∆†§

0.32 ± 0.02 *

0.32 ± 0.01 *∆

0.30 ± 0.02 *

 Sandy clay loam

0.31 ± 0.02

0.39 ± 0.01 *

0.38 ± 0.02 *

0.36 ± 0.01 *

0.39 ± 0.02 *

0.44 ± 0.02 *∆†

0.40 ± 0.02 *

0.42 ± 0.01 *

0.40 ± 0.02 *

  1. Values are represented as means ± one standard deviation. Abbreviations: mGWC, municipal green-waste compost; GAC, granulated activated carbon; WW | 850, high-temperature wood-waste biochar; WW | 540, low-temperature wood-waste biochar; GW | 680, green-waste biochar; CEC, cation exchange capacity; TN, total nitrogen; TOC, total organic carbon. Percentages indicate mass contribution of high carbon organic amendments to the mixtures. Fig. 1 provides further clarifications. All parameters contain n = 5 replicates, with the exception of bulk density (sandy clay loam, n = 3; medium sand, n = 4) and specific surface area (SSA) after dry mixing (n = 2). Total nitrogen, organic carbon and calcium carbonate contents are representative of dry-mixed soils, whereas respired carbon is accumulated total across 30 days of incubation. Differences between treatments were analyzed using one-way ANOVA, with targeted post-hoc orthogonal contrasts restricted to predefined comparisons.
  2. * Significant difference found between the property of the subsoil and amended mixture
  3. ∆ Significant difference found between the property of the the green-waste compost control and a biochar-amended mixture
  4. † Significant difference found between the property of the granulated activated carbon control and a biochar-amended mixture
  5. § Significant difference found between the property of a singular biochar mixture compared to the related dual biochar mixtures
Back to article page