土壤化学是指对于土壤的化学特性的研究。土壤化学受到矿物质、有机物、环境相关等的因素的影响。

直至20世纪60年代末，土壤化学主要着重于土壤中为成土作用做出贡献的或影响植物生长的反应。后来研究延伸到环境污染、有机与无机土壤污染物、潜在的生态健康和环境健康风险。因此，土壤化学的重点由土壤学与农业土壤科学转向环境土壤科学。

Soil chemistry is the study of the chemical characteristics of soil. Soil chemistry is affected by mineral composition, organic matter and environmental factors.

Soil chemistry is the study of the chemical characteristics of soil. Soil chemistry is affected by mineral composition, organic matter and environmental factors. Soil - (i) The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants. (ii) The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and micro organisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics. This definition is from Soil Taxonomy, second edition.