Soil physical and chemical analysis
Soil moisture was determined as the difference from fresh soil to
constant weighted 105 ℃ for 24 h. Soil pH was measured with a digital pH
meter from a soil water suspension (1:2.5 w : v ). Soil
organic C and N were measure with an element analyzer (Vario EL,
Elementar Analysensysteme, Hanau, Germany) with the aliquots
(approximately 10 g) dried soil samples treated with 10 mL 1N HCL for 24
h at room temperature to remove any soil carbonates. The ammonium
(NH4+-N) and nitrate
(NO3--N) were measured by a continuous
flow analyzer (SAN++; Skalar, Breda, the Netherlands), as described by
Yang et al . 2018.