Carbon, nitrogen and biomass activity under different managements system in Rio Verde – Goias State (Brazil)

The aim of this study was verify alterations in soil biologic attributes under different management systems at Cerrado. Soil samples were taken at dry (july 2006) and wet (february 2007) season at Red distrofic Oxisol (50 – 70 % clay) in Rio Verde, Brazil (17o39’07’’S - 51o06’49’’O) under: native Cerrado (CE), 20 years old pasture (PA), 29 years old conventional tillage (CT), and 10 and 15 years old no-tillage (NT - 10 and NT - 15). Were analysed: soil and microbial carbon and nitrogen levels (C, N, Cmic and Nmic), Cmic:C and Nmic:N ratios, basal respiration (BR) and metabolic quotient (qCO2). Higher soil moisture at wet season led 100 % higher Cmic and Nmic and lower qCO2 level than dry season. Among the management systems, the grass cultivation, animal wastes and area reform were possibly majors factors with which led to higher Cmic e Nmic values in PA, indeed under degradation, than any other one. NT adoption was important to increase Cmic and Nmic, and at least after 10 years pointed out higher values than CT.C and N microbial were more sensitive than total C and N, while other biological parameters also did not show differences.