3. Results
3.1 Changes in enzyme activities and microbial CUEC:N
NT significantly increased BG and NAG activities on average relative to CT (Fig. 1). BG and NAG activities decreased with soil depth under NT, whereas soil depth had no influence under CT. Moreover, both variables of N2 was higher than N1 and N3. Compared with N2, N1 and N3 significantly decreased BG and NAG activities at 0-10 cm and 10-25 cm depths (Fig. 1). Moreover, the average value of LAP activity under CT treatment was higher than that of NT (Fig. 1c-d) and it was higher under N2 than under N1 and N3 for CT treatment.
The average value of CUEC:N under CT was increased by 16.2% compared with NT and soil depth did not influence it under the two tillage practices (Fig. 2g–h). The value of CUEC:Nincreased with increasing N application. NT increased the CUEC:N compared with CT in the 0–10 cm and 10–25 cm layers under N1, whereas there was no significant difference between NT and CT under N3. These results showed that increasing N application rates under NT could enhance CUEC:N.