Biomassa microbiana e sua atividade em solos sob diferentes sistemas de preparo e sucessão de culturas

摘要: In this study, microbial biomass and its activity were evaluated on a soil submitted to crop rotations with wheat/soybean wheat/maize under the no-tillage conventional tillage systems. The evaluation was performed an experiment established since 1976 at Experimental Station of Instituto Agronomico do Parana (IAPAR), Londrina (PR), Brazil. Soil samples taken in plough layer (0-15 cm) ten days after planting seven before harvesting summer winter crops during 1992, 1993 1994. basal respiration carbon by fumigation-incubation method, nitrogen fumigation-extraction, determination metabolic coefficient relation Cmic/Corg soil. There few significant differences parameters related above as result different rotations. However, when compared tillage, plots system have shown increases 118 101% biomass, respectively, 73% 96% Cmic/Corg, while quotient (qCO2) has decreased 28%. continuous use system, either or rotation resulted decreases respiration, therefore having measurable long term effects increase C content. Consequently, be good indicator evaluate management alteration.