. 2024 Mar 8;14:5692. doi: 10.1038/s41598-024-54307-2

Table 2.

Changes in soil chemical properties affected by different nitrogen rates and biochar amendments.

Treatments		pH (1:5, H₂O)	EC (dS m⁻¹)	TC (%)	TN (%)	OM (%)	Avail. N (mg kg⁻¹)	Avail. P (mg kg⁻¹)	Exchangeable cations
Treatments		pH (1:5, H₂O)	EC (dS m⁻¹)	TC (%)	TN (%)	OM (%)	Avail. N (mg kg⁻¹)	Avail. P (mg kg⁻¹)	Ca²⁺ (cmol_c kg⁻¹)	K⁺ (cmol_c kg⁻¹)	Mg²⁺ (cmol_c kg⁻¹)	Na⁺ (cmol_c kg⁻¹)
Initial soil		7.00 ± 0.20^c	0.35 ± 0.05^d	0.71 ± 0.19^d	0.11 ± 0.05^b	1.22 ± 0.33^d	24.77 ± 0.76f.	94.10 ± 21.08^b	4.50 ± 0.21^ab	0.21 ± 0.03^c	1.24 ± 0.11^b	0.19 ± 0.00^a
Control		7.45 ± 0.16^a	0.40 ± 0.06^d	0.44 ± 0.23^e	0.04 ± 0.01^c	0.76 ± 0.40^e	48.11 ± 9.34^e	89.26 ± 4.73^b	4.48 ± 0.14^ab	0.23 ± 0.04^c	1.20 ± 0.10^b	0.19 ± 0.01^a
N_0.5		7.16 ± 0.36^bc	0.75 ± 0.39^b	0.61 ± 0.19^d	0.16 ± 0.02^a	1.05 ± 0.33^d	74.51 ± 11.07^d	113.38 ± 3.90^a	4.59 ± 0.10^ab	0.23 ± 0.04^c	1.46 ± 0.05^a	0.18 ± 0.02^a
N_1.0		6.80 ± 0.17^cd	1.12 ± 0.29^a	0.66 ± 0.13^d	0.19 ± 0.03^a	1.14 ± 0.22^d	88.75 ± 17.32^c	117.40 ± 17.30^a	4.62 ± 0.05^ab	0.27 ± 0.05^bc	1.50 ± 0.01^a	0.20 ± 0.01^a
N_2.0		6.59 ± 0.18^e	1.26 ± 0.49^a	0.64 ± 0.18^d	0.21 ± 0.03^a	1.10 ± 0.31^d	104.34 ± 12.46^bc	112.74 ± 9.97^a	4.69 ± 0.30^b	0.29 ± 0.08^bc	1.48 ± 0.18^a	0.21 ± 0.02^a
AB	N_0.5	7.19 ± 0.18^bc	0.52 ± 0.09^c	1.03 ± 0.12^c	0.17 ± 0.02^a	1.78 ± 0.21^c	94.51 ± 16.07^cd	120.69 ± 19.97^a	4.60 ± 0.13^ab	0.23 ± 0.05^c	1.54 ± 0.12^a	0.21 ± 0.05^a
	N_1.0	7.19 ± 0.49^bc	0.58 ± 0.34^c	1.19 ± 0.06^c	0.18 ± 0.02^a	2.05 ± 0.10^c	101.33 ± 14.02^bc	119.69 ± 19.63^a	4.63 ± 1.05^ab	0.33 ± 0.03^b	1.56 ± 0.09^a	0.22 ± 0.04^a
	N_2.0	7.12 ± 0.43^bc	1.09 ± 0.38^a	1.14 ± 0.17^c	0.20 ± 0.03^a	1.97 ± 0.29^c	124.98 ± 25.78^a	115.08 ± 11.34^a	4.90 ± 0.37^a	0.48 ± 0.04^a	1.59 ± 0.08^a	0.22 ± 0.02^a
NB	N_0.5	7.26 ± 0.22^b	0.64 ± 0.37^c	1.64 ± 0.37^b	0.17 ± 0.01^a	2.83 ± 0.64^b	97.90 ± 18.08^c	118.01 ± 17.98^a	4.54 ± 0.57^ab	0.31 ± 0.09^b	1.52 ± 0.03^a	0.20 ± 0.01^a
	N_1.0	7.14 ± 0.36^bc	0.69 ± 0.34^c	1.78 ± 0.68^b	0.18 ± 0.01^a	3.07 ± 1.17^b	115.80 ± 14.48^b	120.56 ± 11.74^a	4.66 ± 0.21^ab	0.37 ± 0.03^ab	1.57 ± 0.25^a	0.22 ± 0.04^a
	N_2.0	7.13 ± 0.69^bc	1.16 ± 0.40^a	1.62 ± 0.49^b	0.21 ± 0.01^a	2.79 ± 0.84^b	143.31 ± 23.44^a	123.44 ± 5.80^a	4.96 ± 0.52^a	0.44 ± 0.09^a	1.56 ± 0.08^a	0.25 ± 0.09^a
BB	N_0.5	7.48 ± 0.21^a	0.67 ± 0.16^c	2.09 ± 0.58^a	0.20 ± 0.01^a	3.60 ± 1.00^a	93.87 ± 17.01^cd	113.42 ± 6.22^a	4.33 ± 0.07^b	0.32 ± 0.04^b	1.55 ± 0.02^a	0.21 ± 0.02^a
	N_1.0	7.44 ± 0.22^a	0.88 ± 0.04^b	2.06 ± 0.53^a	0.21 ± 0.01^a	3.55 ± 0.91^a	104.33 ± 12.46^bc	125.05 ± 9.92^a	4.61 ± 0.34^ab	0.41 ± 0.07^a	1.58 ± 0.11^a	0.26 ± 0.08^a
	N_2.0	7.24 ± 0.64^ab	1.18 ± 0.24^a	2.36 ± 0.45^a	0.23 ± 0.01^a	4.07 ± 0.76^a	138.61 ± 19.82^a	117.17 ± 34.87^a	4.97 ± 0.55^a	0.43 ± 0.06^a	1.57 ± 0.08^a	0.20 ± 0.02^a
p-value		*	**	***	**	***	*	***	**	*	***	***

N_0.5, 160 kg N ha⁻¹; N_1.0, 320 kg N ha⁻¹; N_2.0, 640 kg N ha⁻¹.

AB acidic (pH 6.1) rice husk biochar, NB neutral (pH 7.1) rice husk biochar, BB basic (pH 11.0) rice husk biochar, EC electrical conductivity, TC total carbon, TN total nitrogen, OM organic matter, Avail. N available nitrogen, Avail. P available phosphorus.

*, **, and *** are used to indicate statistically significant differences at the p < 0.05, p < 0.01, and p < 0.001, respectively.

^a^–fEach value with different letters within a column are significantly different from each other as determined by Duncan’s multiple range test (p < 0.05).