Table 1.
Application levels of fertilizers and inhibitors.
Table 2.
Maize N uptake, NUE and harvest index under different fertilization treatments.
Fig 1.
Mean content in the 0–60 cm soil depth band from 5 to 90 days after fertilization.
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. Vertical bars represent LSD0.05 between treatments.
Fig 2.
The activities of urease (A) and nitrate reductase (B) 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. Vertical bars represent LSD0.05 between treatments.
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.
Fig 4.
Correlation analysis between N-cycling genes, enzyme activities and physicochemical parameters in the soil.
OC, organic C; TN, total N; AP and AK, available P and K; MT, moisture; AOA, amoA AOA; AOB, amoA AOB; Ure., urease activity; Nr., nitrate reductase activity. * represents significant correlation (p < 0.05).