Evaluation of the Continuous Application of Different Organic Materials on Soil Surface Charge and Chemical Properties Along the Soil Profile of a Typical Mollisol

Abstract

Innovative agricultural technologies such as organic fertilization have provided long and short-term benefits as far as sustainable soil management is concerned. In this study, five treatments were applied: cow manure (CM), chicken manure (JM), poplar tree leaves (TL), maize straw (MZ), and control (CK). The aim was to evaluate the long-term effects of applying organic materials on soil chemical and electrochemical properties. The highest pH and EC were recorded in JM and CM respectively. The highest cation exchange capacity (CEC) and specific surface area (SSA), were recorded in treatment TL while the application of organic materials increased the CEC and SSA by 24.9-85.5% and 6.9-52.4% respectively. The surface charge characteristics were significantly improved by the organic treatments compared with CK (P<0.05). The application of organic materials increased the surface charge potential (φ0) by 28-35.9% and the surface charge density (σ0) by 21.42-35.71%. Moreover, the electric field strength (E0) and surface charge number (SCN) were increased by 16.6-27.8% and 21.7-94.9% respectively. The soil chemical and electrochemical properties decreased along the soil profile with the exception of pH and EC, which increased with depth. The granulometric properties of organic matter and other physical attributes affected the chemical and electrochemical properties of the soil. The surface charge characteristics were significantly positively correlated with each other and the soil chemical properties as shown by the correlation analysis. The application of organic materials especially treatment TL is recommended as it had a more advantageous effect on enhancing the surface charge characteristics and could improve the quality of agricultural soils.