Fig 3. The N-cycling gene copies under different fertilization treatments.

CK, no N fertilizer input; CF, conventional fertilization; 80%U+UI, 80%U+NI and 80%U+1/2(UI+NI) indicate 80% of urea input with NBPT, with DMPP and with half NBPT and half DMPP, respectively. Different lowercase letters above the bars represent significant differences (p < 0.05) between treatments.