Table 1 Some relevant properties of the soil and biochar used

Sand

g kg^-1

800

-

Silt

g kg^-1

34

-

Clay

g kg^-1

166

-

pH (1:2.5 or 1:20 water)

4.37

9.59

Cation exchange capacity (1 M NH₄OAc, pH 7)

cmol(+) kg^-1

2.34

13.87

Organic C (Walkley & Black)

g kg^-1

6.7

nd^*

Ash content (ASTM D2974 1988)

g kg^-1

963

53

Available P (1 M NH4F/0.5 M HCl, pH 1.8)

mg kg^-1

8

747

Exchangeable K (1 M NH₄OAc, pH 7)

mg kg^-1

51

6895

Exchangeable Mg (1 M NH₄OAc, pH 7)

mg kg^-1

13

908

Exchangeable Ca (1 M NH₄OAc, pH 7)

mg kg^-1

159

9799

Total N (Se/H₂SO₄ + Na₂SO₄)

g kg^-1

1.19

5.1

Total P (Se/H₂SO₄ + Na₂SO₄)

g kg^-1

0.423

1.3

Total K (Se/H₂SO₄ + Na₂SO₄)

g kg^-1

0.998

9.1

Total Mg (Se/H₂SO₄ + Na₂SO₄)

g kg^-1

0.0225

4.3

Total Ca (Se/H₂SO₄ + Na₂SO₄)

g kg^-1

0.0395

14.9