Soil microbial biomass and enzyme activity in six Brazilian oxisols under cropland and native vegetation

Abstract

Oxisols are important soils that have been converted from native vegetation to croplands, and can affect soil biological properties such as microbial biomass and enzyme activity. Thus, the aim of this study was to evaluate the changes on soil microbial biomass and enzyme activity when native vegetation (NV) was converted to cropland (CL), such as maize or sugarcane in six oxisols from São Paulo state, Brazil. Soil microbial biomass C (MBC) and N (MBN), and the activity of arylsulphatase, dehydrogenase and fluorescein diacetate hydrolysis (FDA) were assessed in samples collected at 0-0.20 m. In general, MBC was higher under NV than CL (about + 40%), while MBN and FDA did not show a consistent pattern between NV and CL. All soils showed higher values of arylsulfatase (increased from 101 to 717%) and dehydrogenase (increased 15 to 220%) under NV than CL. In conclusion, soil microbial biomass C is usually higher under native vegetation than cropland. Arylsulphatase and dehydrogenase were the attributes that presented better differentiation between native and cropped soils.

Efeitos da compostagem termofílica industrial na qualidade do lodo de esgoto e na dissipação de resistência antimicrobiana em solos

“…Usualmente a maior atividade enzimática é vinculada a maiores valores de CBM devido à capacidade conjunta em controlar a taxa de decomposição do carbono orgânico do solo (Ferreira et al, 2011;Zuber & Villamil, 2016;Ren et al, 2017;Barbosa et al, 2023), porém, essa relação nem sempre é óbvia, uma vez que os microrganismos e processos de degradação dos componentes orgânicos do solo são altamente diversos (Salazar et al, 2011). Além disso, nem toda enzima do solo é constitutiva da estrutura celular dos microrganismos, sendo a maioria aqui avaliadas encontradas extracelularmente e, por isso, a maior atividade enzimática não necessariamente está sempre vinculada à maior quantidade de CBM, conforme visto também em outros estudos (Moorhead et al, 2013;de Melo et al, 2020).…”