Application of biochar-coated urea controlled loss of fertilizer nitrogen and increased nitrogen use efficiency

Chemical and Biological Technologies in Agriculture

Table 2 Cumulative leaching loss of NO₃⁻–N, NH₄⁺–N and inorganic N in different fertilized soils during experiment for 65 days (mg/kg)

Treatments	NH₄⁺–N	NO₃⁻–N	total nitrogen
CK	0.38 ± 0.04e	7.93 ± 0.98d	6.34 ± 2.19f
U1	4.47 ± 0.63a	60.62 ± 0.61a	78.03 ± 7.50a
U2	3.95 ± 0.55ab	55.31 ± 5.11ab	67.65 ± 1.23b
U1 + B	4.08 ± 0.21ab	57.11 ± 5.21a	74.95 ± 6.15ab
U2 + B	3.62 ± 0.03b	45.68 ± 7.28c	57.78 ± 6.10c
BCU1	2.74 ± 0.35c	48.61 ± 4.58bc	49.81 ± 2.33 cd
BCU2	2.10 ± 0.29d	41.67 ± 5.36c	42.94 ± 4.89de
BCU1 + B	1.68 ± 0.04d	40.44 ± 2.89c	41.35 ± 2.59e

CK, no fertilizer; U1, urea at 100% N rate; U2, urea at 80% N rate; U1 + B, biochar combined with urea at 100% N rate; U2 + B, biochar combined with urea at 80% N rate; BCU1, biochar-coated urea at 100% N rate; BCU2, biochar-coated urea at 80% N rate; BCU1 + B, biochar combined with biochar-coated urea at 100% N rate
Different letters in the same column indicate a significant difference at the 5% level according to the LSD test