title: Assessment and kinetics of soil phosphatase in Brazilian Savanna systems.
abstract: The activity and kinetics of soil phosphatases are important indicators to evaluate soil quality in specific sites such as the Cerrado (Brazilian Savanna). This study aimed to determine the activity and kinetic parameters of soil phosphatase in Cerrado systems. Soil phosphatase activity was assessed in samples of native Cerrado (NC), no-tillage (NT), conventional tillage (CT) and pasture with Brachiaria brizantha (PBb) and evaluated with acetate buffer (AB), tris-HCl buffer (TB), modified universal buffer (MUB) and low MUB. The Michaelis-Menten equation and Eadie-Hofstee model were applied to obtain the kinetic parameters of soil phosphatase using different concentrations of p-nitrophenol phosphate (p-NPP). MUB showed the lowest soil phosphatase activity in all soils whereas AB in NC and NT presented the highest. Low MUB decreased interferences in the assessment of soil phosphatase activity when compared to MUB, suggesting that organic acids interfere on the soil phosphatase activity. In NC and NT, soil phosphatase activity performed with TB was similar to AB and low MUB. Km values from the Michaels-Menten equation were higher in NC than in NT, which indicate a lower affinity of phosphatase activity for the substrate in NC. Vmax values were also higher in NC than in NT. The Eadie-Hofstee model suggests that NC had more phosphatase isoforms than NT. The study showed that buffer type is of fundamental importance when assessing soil phosphatase activity in Cerrado soils.
authors.affiliation: Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Rua Amazonas, s/n, 38400-902 Uberlândia, MG, Brasil, Universidade Federal de Uberlândia, Universidade Federal de Uberlândia, Instituto de Ciências Agrárias, Uberlândia MG , Brasil.
authors.forename: Adão S
authors.initials: AS
authors.lastname: Ferreira
authors.affiliation: Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Rua Amazonas, s/n, 38400-902 Uberlândia, MG, Brasil, Universidade Federal de Uberlândia, Universidade Federal de Uberlândia, Instituto de Ciências Agrárias, Uberlândia MG , Brasil.
authors.forename: Suéllen P
authors.initials: SP
authors.lastname: Espíndola
authors.affiliation: Instituto de Biotecnologia, Universidade Federal de Goiás/UFG, Campus Catalão, Av. Dr. Lamartine Pinto de Avelar, 1120, 75704-020 Catalão, GO, Brasil, Universidade Federal de Goiás, Universidade Federal de Goiás, Instituto de Biotecnologia, Catalão GO , Brasil.
authors.forename: Maria Rita C
authors.initials: MR
authors.lastname: Campos
mesh_terms: D001938:Brazil; D065948:Grassland; D007700:Kinetics; D010744:Phosphoric Monoester Hydrolases / Q000493:pharmacokinetics*; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D010744:Phosphoric Monoester Hydrolases