Macro cn analyzer

Soil moisture content was determined by oven-drying the samples at 105 °C overnight.
Soil pH was assessed using a fresh soil to water ratio of 2.5 using a Delta pH-meter (Mettler-Toledo Instruments Co., Columbus, OH, USA). Total carbon and total nitrogen were measured on a LECO macro-CN analyzer (LECO, St. Joseph, MI, USA).
Dissolved organic carbon (DOC) was determined by an extraction method described by Jones and Willett (2006) and measured on a TOC analyzer (Shimadzu TOC-500A, Japan).

Soil water content was determined by oven-drying the samples at 105°C, and soil texture was analyzed using the pipette method (Gee and Bauder,1986) . Soil pH was measured using a fresh soil to water ratio of 1: 2.5 with a Delta pH-meter, and soil organic carbon (SOC) was determined using the K2CrO7 oxidation titration method (Walkley & Black 1934) . Total carbon (TC) and total nitrogen (TN) were measured on a LECO macro-CN analyzer (LECO, St. Joseph, MI, USA). Inorganic N and labile carbon in the soils were extracted with 0.5 M K2SO4 in a ratio of 1:5 by shaking at 200 rpm for 1 h and filtered through 0.45-μm Millipore filter paper. Total C and N concentrations in the extracts were analyzed by TOC analyzer with total nitrogen unit (TOC-L Analyzer, Shimadzu, Japan). In parallel, the carbon in microbial biomass (MBC) was determined using the fumigation-extraction method (Vance et al., 1987) . For each measurement of respiration rate, approximately 10 g of fresh soil (within 48 h after sampling) was incubated in a 120 ml container at 25 °C for 24 h. At the end of this period, CO2 concentrations in headspace were measured using an Agilent-7890a gas chromatograph equipped with a flame ionization detector (FID) and an electron capture detector (ECD) (Agilent Technologies, Wilmington, DE, USA). Soil respiration rates were calculated from the net accumulation of CO2 over time.