Table 4.

Summary of two-way ANOVA results for the soil chemical properties in terms of soil sample years and parthenium biochar dosages.

Source of variations	DF	pH (H2O)		pH (KCl)		EC (ms/cm)		Ca (cmol+/kg)		K (cmol+/kg)		Na (cmol+/kg)		Mg (cmol+/kg)		CEC(cmol+/kg)		AvP (ppm)		OC (%)
		MS	P	MS	P	MS	P	MS	P	MS	P	MS	P	MS	P	MS	P	MS	P	MS	P
SSY	1	3.17	p ≤ 0.01	4.02	p ≤ 0.01	2.14	p ≤ 0.001	85.5	p ≤ 0.001	34.0	p ≤ 0.001	0.3	p ≤ 0.001	41.1	p ≤ 0.01	268.5	p ≤ 0.001	4285.7	p ≤ 0.001	5.2	p ≤ 0.001
PBD	5	4.9	p ≤ 0.001	4.04	p ≤ 0.001	1.6	p ≤ 0.001	25.9	p ≤ 0.001	35.7	p ≤ 0.001	0.2	p ≤ 0.001	8.9	p > 0.05	73.6	p ≤ 0.001	2561.7	p ≤ 0.001	1.84	p ≤ 0.001
SSY∗PBD	5	0.14	p > 0.05	0.05	p > 0.05	0.15	p ≤ 0.001	6.5	p ≤ 0.005	2.7	p > 0.05	0.009	p ≤ 0.005	2.5	p > 0.05	11.9	p ≤ 0.005	227.8	p ≤ 0.001	0.34	p ≤ 0.001
Error	24	0.26	—	0.28	—	1.015	—	1.11	—	11.16	—	0.002	—	2.6	—	2.3	—	19.8	—	0.0016	—
Mean		7.1	—	6.44	—	0.01	—	15.4	—	4.5	—	0.59	—	6.2	—	26.24	—	48.3	—	1.5	—
R-square (R2)		0.82	—	0.78	—	0.97	—	0.90	—	0.89	—	0.81	—	0.60	—	0.92	—	0.97	—	0.97	—

SSY, soil sample years; PBD, parthenium biochar dosages; MS, mean square; P, probability level; and DF, degree of freedom.