3.1.1 Soil chemical properties
The soil pH gradually decreased with the increase of N addition
concentration, and
the
pH value in HN treatment significantly decreased to 5.24 (P<0.05) (Table 1). TP content was significantly increased by
16.7% in the MN treatment. The
AP content was significantly reduced after N addition. There were
significant changes in NH4+-N and
NO3--N content.
The
NH4+-N content increased with the
concentration of N addition increasingly, and there was a significant
increase in MN and HN treatments. The
NO3--N content in the LN treatment was
significantly increased and was significantly decreased in the HN
treatment.