Acidity meter

Soil physicochemical analysis included the determination of SWC, pH, electrical conductivity (EC), TOC, TN, nitrate–nitrogen (NO₃^–-N), ammonium nitrogen (NH₄⁺-N), and available phosphorus (AP). SWC was calculated as follows: SWC = (W2 − W3) × 100 / (W3 − W1), where W1 was the weight of the aluminum box, W2 was the weight of the initial soil sample with the aluminum box, and W3 was the weight of the dried soil sample with the aluminum box. Soil pH and EC values were determined by the acidity meter and conductivity meter (METTLER TOLEDO, Switzerland), respectively. TOC and TN were measured by Fisher 2000 elemental analyzer (Thermo Fisher Scientific, Italy). NH₄⁺-N and NO₃^–-N were determined by a flow autoanalyzer (FIA Compact, Germany). AP was measured by the sodium bicarbonate extraction molybdenum antimony anti-colorimetric method (Jinghua, China).

Soil physiochemical properties included SWC, pH, electronic conductivity (EC), total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP). SWC was calculated as follows: SWC = (W₂–W₃)*100/(W₂−W₁), where W₁ was the weight of the aluminum box, W₂ was the weight of the initial soil sample with the aluminum box, and W₃ was the weight of the dried soil sample with the aluminum box, which dried at 65°C to constant weight. Soil pH and electrical conductivity (EC) were measured with an acidity meter and conductivity meter (METTLER TOLEDO), respectively (Guo, Li, et al., 2018; Guo, Weise, et al., 2018). TOC was determined by the TOC determinator (MACRO) (Wang, Qin, Cai, Meng, & Zhang, 2014). TN was determined by the Kelvin determination apparatus (FOSS Kjeltec) (Ge, Li, Fan, Hou, & Liang, 2010). TP was measured by the sodium hydroxide fusion‐molybdenum antimony colorimetric method (JingHua) (Bao, 2013).