San system autoanalyzer

The soil chemical properties were analyzed from dried soil samples. Using a pH and EC meter (SP2000, Skalar BV, Netherlands), the electrical conductivity (EC) and pH of the soil were determined in a 1:5 (w/v) soil: deionized distilled water suspension. A titrando automatic titrator (Metrohm 888, Switzerland) was used to analyze soil organic matter (SOM). The BaCl₂-H₂SO₄ exchange method^{55 (link)} was used to determine the soil cation exchange capacity (CEC). The ammonium-nitrogen (NH₄⁺) nitrate-nitrogen (NO₃⁻) concentration in the soil were measured colorimetrically by salicylate method^{56 (link)} and cadmium reduction method^{57 (link)}, respectively, using BLTEC QuAAtro (BLTEC KK, Japan). The soil total nitrogen (TN) concentration was determined by the method described by Dumas^{58 (link)} with S832DR (Leco, USA). Soil exchangeable potassium (K) concentration was analyzed using a PerkinElmer® Optima 8300 ICP-OES (PerkinElmer, Inc., MA, USA). The soil available P₂O₅ (AP) concentration was analyzed using a SKALAR San +  + system autoanalyzer (Skalar Analytical B.V., Breda, Netherlands).

The soil chemical properties were analyzed according to NIAST (2010) at Kyungpook National University, South Korea. A pH and EC meter (SP2000, Skalar BV, Netherlands) was used to measure the soil pH and EC. A titration method using an automatic titrator (Metrohm 888, Switzerland) was employed to assess the soil organic matter (SOM) content. Soil ammonium ( ${\text{NH}}_4^{+}$ ) and nitrate ( ${\text{NO}}_3^{-}$ ) concentrations were measured using cadmium reduction and salicylate colorimetric methods, respectively, using BLTEC QuAAtro (BLTEC KK, Osaka, Japan). The method employed by Dumas was used to determine the total nitrogen (TN) concentration with S832DR (Leco, USA). The concentrations of exchangeable potassium (K) and available P₂O₅ (AP) in the soil were measured using a PerkinElmer Optima 8300 ICP-OES (PerkinElmer, MA, USA) and SKALAR San++ system autoanalyzer (Skalar Analytical B.V., Breda, Netherlands), respectively. The soil cation exchange capacity (CEC) was measured using the BaCl₂-H₂SO₄ exchange method.