Using Soil Enzymatic Activities to Evaluate Soil Health in Long-Term Integrated Production Systems

Soil organic carbon is essential for soil health. The β-glycosidase (BG) enzyme is recognized as a bioindicator of changes in the carbon cycle and is commonly used to assess soil health. The arylsulfatase (ARYL) enzyme acts in the sulfur cycle, associated with the mineralization of organic sulfate compounds. These enzymatic activities were evaluated in a 14-year field experiment, from Embrapa Southeast Livestock Center, located in a transition area of Brazilian Atlantic Forest and Cerrado biomes, encompassing different production systems: integration crop-livestock-forest (ICLF), integration livestock-forest (ILF), integration crop-livestock (ICL), intensive managed pasture (INT), extensive pasture (EXT), and native forest (FO). The BG and ARYL activities were determined by incubating soil samples, followed by UV–Vis spectrophotometric quantification of released p-nitrophenol, and expressed in μg of p-nitrophenol g^-1 of soil h^-1.  BG activity ranged from 63.2 to 155.9 μg p-nitrophenol g^-1 soil h^-1, in the following order: EXT< ICLF< ILF< FO< INT< ICL, with ICL system with highest value and the INT system presenting the second higher value. Arylsulfatase activity ranged from 191.3 to 745.5 μg p-nitrophenol g^-1 soil h^-1, in the following order: EXT<ICLF< ILF=ICL< INT< FO, with ICL system showing intermediate activity (262.5 μg p-nitrophenol g^-1 soil h^-1). Higher enzyme activities may reflect greater inputs of plant residues, indicating enhanced carbon and sulfur cycling. Overall, integrated production systems and intensively managed pastures exhibited higher BG and ARYL activities than EXT, highlighting the importance of increasing organic inputs to foster enzymatic activity and improve soil health.