. 2019 Jun 4;7:e7027. doi: 10.7717/peerj.7027

Table 2. Basic physical properties of soil under different biochar treatments with or without nitrogen fertilization.

Treatment^a		Bulk density (g cm⁻³)						Soil porosity (%)						Capillary porosity (%)						Air-filled porosity (%)
		B400			B700			B400			B700			B400			B700			B400			B700
		Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL	Mean	Std. error	SL
N0	C0	1.49	0.03	a	1.42	0.05	bc	43.83	1.17	b	46.23	2.03	c	34.73	1.24	a	34.33	0.68	ab	9.09	1.12	a	11.90	2.09	bcd
	C0.7	1.42	0.07	ab	1.42	0.01	bcd	46.32	2.71	ab	46.58	0.34	bc	35.29	0.68	a	37.29	2.75	a	11.03	2.10	a	9.28	2.45	d
	C2.1	1.26	0.17	b	1.27	0.06	e	52.54	6.52	a	52.05	2.18	a	33.17	2.56	ab	34.98	0.22	ab	19.37	9.05	a	17.07	1.95	a
N210	C0	1.40	0.10	ab	1.49	0.00	a	47.20	3.60	ab	43.62	0.15	d	29.43	2.56	b	30.10	1.53	c	17.77	6.07	a	13.51	1.58	bc
	C0.7	1.38	0.02	ab	1.43	0.04	ab	48.09	0.71	ab	46.07	1.45	c	35.15	5.19	a	34.14	1.12	b	12.94	5.84	a	11.93	2.18	bcd
	C2.1	1.31	0.07	b	1.35	0.04	d	50.43	2.70	a	49.09	1.46	b	34.41	2.70	ab	35.30	0.13	ab	16.02	4.73	a	13.78	1.54	abc
N168	C0	1.41	0.06	ab	1.43	0.03	ab	46.70	2.36	ab	45.96	1.22	c	32.94	0.69	ab	32.97	1.20	b	13.76	3.05	a	12.99	2.41	bc
	C0.7	1.35	0.08	ab	1.38	0.05	bcd	48.95	3.04	ab	47.92	1.77	bc	32.68	2.78	ab	37.30	2.60	a	16.27	5.30	a	10.62	0.92	cd
	C2.1	1.28	0.03	b	1.36	0.06	cd	51.54	1.11	a	48.77	2.17	b	34.37	1.39	ab	33.97	1.20	b	17.17	2.48	a	14.80	3.36	ab

Notes.

B400 and B700 represent biochar prepared by pyrolysis at temperatures of 400 and 700 °C , respectively; C0, C0.7, and C2.1 represent biochar application rates of 0, 0.7%, and 2.1% (w/w), respectively; and N0, N210, and N168 represent urea-nitrogen fertilizer levels of 0, 168, and 210 kg N ha ⁻¹, respectively. SL, significant level. Lowercase letters within each column are significantly different at p <0.05.