Impact of land degradation on soil microbial biomass and activity in northeast Brazil - Nunes, Janaina S; Araújo, Ademir Sérgio Ferreira de; Nunes, L.A.P.L.; Lima, L.M.; Carneiro, Romero Francisco Vieira; Salviano, Adeodato Ari Cavalcante; Tsai, Siu Mui (Pedosphere, 2012)