Table 4. Recovery and loss of ¹⁵ N-labeled urea in the rice-soil system under different biochar treatments at the harvest stage.

Temperaturea	Treatment		Recovery of 15N in rice (mg pot−1)		Residual soil 15N content (mg pot−1)		Residual soil 15N rate (%)		Recovery of 15N in rice-soil system (mg pot−1)		Recovery rate in rice-soil system (%)		15N lost (mg pot−1)		15N loss rate (%)
			Mean	Std. error	Mean	Std. error	Mean	Std. error	Mean	Std. error	Mean	Std. error	Mean	Std. error	Mean	Std. error
B400	N210	C0	316.03	13.47	169.24	134.51	8.46	6.73	485.27	125.44	24.26	6.27	1,514.73	125.44	75.74	6.27
		C0.7	248.08	31.50	159.68	18.06	7.98	0.90	407.76	19.31	20.39	0.97	1,592.24	19.31	79.61	0.97
		C2.1	142.13	42.86	313.59	146.55	15.68	7.33	455.72	176.95	22.79	8.85	1,544.28	176.95	77.21	8.85
	N168	C0	245.59	2.39	78.19	27.59	4.86	1.71	323.78	27.74	20.11	1.72	1,286.22	27.74	79.89	1.72
		C0.7	202.32	4.08	177.97	29.45	11.05	1.83	380.30	33.09	23.62	2.06	1,229.70	33.09	76.38	2.06
		C2.1	113.63	18.83	426.93	268.08	26.52	16.65	540.56	249.26	33.58	15.48	1,069.44	249.26	66.42	15.48
B700	N210	C0	306.00	25.56	246.63	37.83	12.33	1.89	552.63	15.52	27.63	0.78	1,447.37	15.52	72.37	0.78
		C0.7	230.51	54.28	213.57	74.53	10.68	3.73	444.08	41.30	22.20	2.06	1,555.92	41.30	77.80	2.06
		C2.1	171.26	57.10	288.98	23.15	14.45	1.16	460.24	66.52	23.01	3.33	1,539.76	66.52	76.99	3.33
	N168	C0	245.51	21.15	92.85	26.85	5.77	1.67	338.36	31.18	21.02	1.94	1,271.64	31.18	78.98	1.94
		C0.7	211.12	24.25	85.53	27.89	5.31	1.73	296.64	52.14	18.43	3.24	1,313.36	52.14	81.57	3.24
		C2.1	109.21	21.22	391.56	97.98	24.32	6.09	500.77	118.94	31.10	7.39	1,109.23	118.94	68.90	7.39

Notes.

^aB400 and B700

^bC0, C0.7, and C2.1; and N0, N210, and N168 are defined in Table 2 footnote.