Effects of Returning Organic Fertilizer and Biochar to Soil on Surface Electrochemical Properties and Nutrients

Abstract

The soil application of organic materials, such as biochar and organic fertilizers, serves as an important approach to maintaining soil nutrient cycling and enhancing soil quality. Here the effects of biochar and organic fertilizer application were comparatively analyzed relative to soil organic matter, NPK (nitrogen, phosphorus, potassium) content, and soil surface electrochemical properties. The primary factors influencing soil surface electrochemical properties were identified. It was found that application of two organic materials could increase the contents of total nutrients and available nutrients. Among all indicators, nitrate nitrogen showed the most significant increase, with T1 and T2 increasing by 34.2% and 75.7% compared to CK, respectively. The two organic materials enhanced soil surface charge quantity, specific surface area, and surface charge density. SOC and HS contents were identified as the top two influencing factors for changes in soil surface electrochemical properties. The explanation index of SOC reached 70.1% and 39.4% for T1 and T2, while those of HS were 20.3% and 31.2%, respectively. These efforts elucidated the impacts of the return of organic fertilizer and biochar to the field on soil surface electrochemical properties, which could provide data support for enhancing arable land quality and fostering healthy soil development.