Table 2.

Unimodal van Genuchten model parameters according to Equation (3). The averaged bulk densities of the samples and Available Water Content (AWC) values derived from the difference between soil water contents at pF = 2.0 and 4.2.

Biochar Dose	Biochar Size Fraction	Bulk Density (mean ± SD)	${\mathit{\theta }}_{\mathit{S}}$	${\mathit{\theta }}_{\mathit{r}}$	$\mathit{\alpha }$	$\mathit{n}$	AWC	$\mathit{\Delta }$
wt.%	µm	g cm−3	m3 m−3	m3 m−3	cm−1		m3 m−3	m3 m−3
0		1.460 ± 0.029	0.3794	0.0747	0.067	1.692	0.078
0.95	<50	1.666 ± 0.029	0.3082	0.0594	0.017	1.432	0.155	0.077
2.24	<50	1.665 ± 0.025	0.3075	0.0597	0.015	1.559	0.157	0.079
4.76	<50	1.580 ± 0.018	0.3381	0	0.102	1.069	0.084	0.006
9.52	<50	1.523 ± 0.008	0.3662	0.0002	0.645	1.028	0.043	−0.035
0.95	50–100	1.666 ± 0.036	0.3131	0.0501	0.021	1.447	0.152	0.075
2.24	50–100	1.627 ± 0.021	0.3191	0.0637	0.017	1.411	0.157	0.080
4.76	50–100	1.563 ± 0.023	0.3386	0.0765	0.024	1.166	0.119	0.041
9.52	50–100	1.524 ± 0.017	0.3627	0	0.069	1.061	0.084	0.006
0.95	100–250	1.511 ± 0.004	0.3498	0.0684	0.029	1.946	0.097	0.020
2.24	100–250	1.512 ± 0.001	0.3516	0.0718	0.031	1.530	0.135	0.057
4.76	100–250	1.534 ± 0.003	0.3406	0.0719	0.028	1.321	0.145	0.067
9.52	100–250	1.481 ± 0.005	0.3804	0.1038	0.042	1.172	0.120	0.043
0.95	<2000	1.540 ± 0.022	0.4024	0.0628	0.151	1.392	0.100	0.023
2.24	<2000	1.440 ± 0.008	0.418	0.0949	0.126	1.435	0.095	0.017
4.76	<2000	1.327 ± 0.033	0.4209	0.1078	0.117	1.477	0.088	0.010

SD–the standard deviation, ${\theta }_S$—saturation soil water content, ${\theta }_r$—residual soil water content, $\alpha$—air entry pressure, $n$—dimensionless parameter.