Coapplication of Chicken Litter Biochar and Urea Only to Improve Nutrients Use Efficiency and Yield of Oryza sativa L. Cultivation on a Tropical Acid Soil

Table 6

Effects of biochar and nitrogen fertilization on soil chemical properties in the field study.

Treatment	T1	T2	T4	T5	T6	T7	T8	Before
pHw	4.6^a  ±  0.16	4.6^a  ±  0.20	4.9^a  ±  0.20	4.9^a  ±  0.19	5.0^a  ±  0.14	4.7^a  ±  0.17	4.5^a  ±  0.11	4.9^a  ±  0.04
	%
Organic matter	7.5^c  ±  0.65	8.3^c  ±  1.38	15.3^a  ±  1.55	13.0^a  ±  0.95	14.3^ab  ±  0.91	13.3^a  ±  0.25	14.5^a  ±  0.95	10.8^bc  ±  0.85
Total carbon	0.87^c  ±  0.07	0.96^c  ±  0.16	1.77^a  ±  0.18	1.51^a  ±  0.11	1.65^b  ±  0.11	1.54^a  ±  0.03	1.68^a  ±  0.11	1.25^bc  ±  0.10
Total N	0.04^b  ±  0.008	0.05^b  ±  0.013	0.11^a  ±  0.013	0.11^a  ±  0.013	0.09^ab  ±  0.013	0.09^ab  ±  0.007	0.07^b  ±  0.008	0.05^b  ±  0.007
	mg kg^−1
Available	0.88^a  ±  0.18	1.05^a  ±  0.20	2.10^a  ±  0.29	1.75^a  ±  0.20	1.75^a  ±  0.20	1.93^a  ±  0.34	1.40^a  ±  0.29	1.05^a  ±  0.35
Exchangeable	1.93^d  ±  0.18	3.33^d  ±  0.34	3.68^cd  ±  0.18	2.80^a  ±  0.08	2.98^bc  ±  0.15	2.98^abc  ±  0.18	2.28^ab  ±  0.22	1.58^abc  ±  0.18
Available P	1.14^a  ±  0.18	2.64^a  ±  0.21	3.60^a  ±  0.54	4.88^a  ±  0.82	4.03^a  ±  0.74	2.64^a  ±  0.49	3.34^a  ±  2.08	2.84^a  ±  0.64
Total P	68.03^a  ±  12.99	77.35^a  ±  6.39	77.06^a  ±  7.97	86.22^a  ±  8.08	74.02^a  ±  5.63	83.05^a  ±  8.31	76.94^a  ±  2.29	64.80^a  ±  4.64
	cmol kg^−1
Total K	2.89^a  ±  0.56	2.28^a  ±  0.17	1.76^a  ±  0.28	2.22^a  ±  0.81	1.92^a  ±  0.14	2.87^a  ±  1.12	2.65^a  ±  0.80	3.30^a  ±  1.14
Available K	0.40^d  ±  0.05	1.07^ab  ±  0.05	0.71^bc  ±  0.05	0.75^bc  ±  0.03	0.99^ab  ±  0.18	0.66^cd  ±  0.06	0.37^d  ±  0.06	1.01^ab  ±  0.12
CEC	2.88^c  ±  0.18	2.75^c  ±  0.36	6.65^ab  ±  0.68	5.93^ab  ±  0.22	5.55^ab  ±  0.54	7.25^a  ±  0.48	6.50^ab  ±  0.59	4.58^bc  ±  0.10
Exchangeable Acidity	1.10^ab  ±  0.04	1.06^abc  ±  0.13	0.73^cd  ±  0.05	0.74^cd  ±  0.05	0.55^d  ±  0.04	0.79^bcd  ±  0.09	0.68^d  ±  0.06	1.32^a  ±  0.07
Exchangeable Al^3+	0.91^a  ±  0.06	0.71^b  ±  0.07	0.43^d  ±  0.04	0.40^d  ±  0.01	0.36^d  ±  0.03	0.52^d  ±  0.04	0.49^bc  ±  0.03	1.24^cd  ±  0.05
Exchangeable H^+	0.19^a  ±  0.07	0.35^a  ±  0.06	0.30^a  ±  0.08	0.34^a  ±  0.06	0.19^a  ±  0.03	0.27^a  ±  0.05	0.19^a  ±  0.07	0.08^a  ±  0.02
Exchangeable Cu^2+	0.0076^a  ±  0.0004	0.0069^b  ±  0.0002	0.0069^b  ±  0.0009	0.0060^ab  ±  0.0005	0.0052^ab  ±  0.0010	0.0032^ab  ±  0.0001	0.0067^b  ±  0.0002	0.0119^ab  ±  0.0006
Exchangeable Mn^2+	0.44^a  ±  0.06	0.39^a  ±  0.07	0.37^a  ±  0.05	0.37^a  ±  0.06	0.40^a  ±  0.04	0.56^a  ±  0.05	0.33^a  ±  0.07	0.27^a  ±  0.07
Exchangeable Fe^2+	1.88^b  ±  0.08	1.82^a  ±  0.07	0.15^b  ±  0.10	0.04^b  ±  0.01	0.06^b  ±  0.01	0.05^b  ±  0.02	0.08^a  ±  0.01	0.16^b  ±  0.01
Exchangeable Zn^2+	0.0017^a  ±  0.0004	0.0018^b  ±  0.0009	0.0011^ab  ±  0.0003	0.0009^b  ±  0.0002	0.0023^b  ±  0.0011	0.0018^ab  ±  0.0012	0.0037^b  ±  0.0019	0.0068^b  ±  0.0008
Exchangeable Na^+	5.21^a  ±  0.34	4.77^a  ±  0.21	4.49^a  ±  0.09	4.43^a  ±  0.08	4.68^a  ±  0.18	4.32^a  ±  0.15	4.87^a  ±  0.63	5.25^a  ±  0.39
Exchangeable Ca^2+	17.70^a  ±  1.37	18.12^b  ±  1.23	19.41^b  ±  1.17	19.82^ab  ±  0.70	18.96^ab  ±  1.93	19.90^ab  ±  0.47	16.89^b  ±  1.85	26.39^ab  ±  2.76
Exchangeable Mg^2+	14.79^b  ±  0.28	12.22^a  ±  2.01	11.23^a  ±  1.30	11.42^ab  ±  0.56	12.14^ab  ±  1.48	15.55^a  ±  1.31	13.23^a  ±  2.25	5.27^a  ±  0.93

Different letters within a row indicate significant difference between means of four replicates ± standard error using Tukey’s test at ≤ 0.05.