Table 1
Chemical properties and potential nitrification rates (PNR) of soil with different concentrations of N addition.
Treatment N addition (g N m2 yr1
) pH (H2O) Organic matter (%) NHþ
4 N (mg/kg) NO
3 AN (mg/kg) PNR (mg NO
2 AN kg1 d1
)
N0(CK) 0 6.63 ± 0.02ea 3.35 ± 0.26 3.74 ± 0.84a 2.27 ± 0.82a 11.57 ± 3.16c
N1.75 1.75 6.44 ± 011d 3.56 ± 0.37 6.90 ± 2.56a 12.27 ± 3.61ab 13.68 ± 2.19c
N5.25 5.25 6.37 ± 0.10d 3.68 ± 0.69 21.42 ± 1.42ab 26.86 ± 14.02ab 10.57 ± 3.98c
N10.5 10.5 5.93 ± 0.03c 3.17 ± 0.24 27.73 ± 18.9ab 27.93 ± 19.55ab 6.07 ± 0.48b
N17.5 17.5 5.58 ± 0.06b 3.51 ± 0.28 43.16 ± 22.1b 44.06 ± 3.75b 4.85 ± 2.26ab
N28 28 4.93 ± 0.19a 3.56 ± 0.37 87.52 ± 17.0c 97.9 ± 33.60c 1.74 ± 1.25a
a Mean ± SD. (n = 4) Values within the same column containing a same letter do not differ at P < 0.05.
X. Li