ABSTRACT
Pig slurry use as soil fertilizer is a common practice in southern Brazil. In spite of the benefits of reusing waste, this practice poses serious environmental risks. Microbiological indicators of soil quality are very sensitive and allow soil environment conditions to be monitored. The aim of this study was to evaluate the microbiological quality of pasture soils with different histories of successive use of pig slurry. Determinations were made of C content in the microbial biomass, soil microbial respiration, metabolic quotient (qCO2), activity of the enzymes β-glycosidase and urease, and fluorescein diacetate (FDA) hydrolysis in grazing areas under the use of pig slurry for two (A2) and 14 years (A14) and in a native forest (NF) area. The successive use of pig slurry on pasture did not affect C biomass and soil microbial respiration, which varied according to the time of collection. The qCO2 was not affected by the use of pig slurry in the soil. Soil enzymatic activity was affected by the use of pig slurry; urease and FDA were sensitive in detecting differences in soil activity with the use of pig slurry, whereas the β-glycosidase enzyme did not allow differentiation among the areas studied.
soil quality; carbon; biomass; respiration; enzymatic activity
