Soil Chemical and Microbial Analysis

The soil samples were air-dried, ground and sieved through a 2-mm mesh. Soil pH was measured in a soil-to-water ratio of 1:1 using a glass electrode pH meter (FiveGo, Mettler Toledo, Greifensee, Switzerland). Soil organic carbon (SOC) and total nitrogen (TN) contents were determined using dichromate oxidization and Kjeldahl digestion [35 ], and available nitrogen (AN) as described earlier [36 (link)]. Total phosphorus (TP) and total potassium (TK) contents were determined after digestion in HF-HClO₄. Soil moisture (MO) content was measured by drying the fresh soil samples at 105 °C until a constant weight [37 ]. Available phosphorus (AP) and available potassium (AK) contents were determined using sodium bicarbonate and ammonium acetate extraction [14 , 38 ]. Soil microbial biomass C (SMBC) and biomass N (SMBN) contents were estimated by using chloroform fumigation extraction as described earlier [39 (link)].