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Winter forage deficit is a recurrent issue in rangelands of southern Brazil, generating nutritional deficiencies to herbivores kept in such conditions, being more decisive in shallow soils. We studied 12 combinations of fertilization and liming related to autumn grazing deferment of rangeland on shallow basaltic soil in order to accumulate forage for use in winter. No significant differences were (P<0,05) observed in total forage mass (MF) and green forage mass (MFV) as a function of treatment. A quadratic effect for MF and MFV according to the time of deferral, and the maximum accumulation occurred at 96 days (2965 Kg.ha-1 and 1446 Kg.ha-1, respectively). The dead material increased linearly with time. With multivariate analysis we can see that these variables were influenced by the soil depth of the plots. The greater depth were associated with higher MF and lower amount of bare ground. In plots of shallower soil (< 5 cm) ruderal species predominated, with forage value lower than what prevailed in deeper soils. [ABSTRACT FROM AUTHOR]

The soil microbial biomass is the living fraction of organic matter, being responsible for several biological and biochemical processes of the soil and influenced by the conditions imposed by the environment. To evaluate the effect of grazing on changes in soil microbial attributes we studied four grazing intensities based on natural grassland of Pampa Biome: 4, 8, 12 and 16 kg of dry matter per day per 100 kg of animal live weight, compared to an area without grazing. We used rand omized block design with two replications. Samples were taken on 11/23/20 11 and analyzed to determi ne the levels of soil organic matter (SOM), microbial biomass, nitrogen, respiration and metabolic quotient. The results showed that at intermediate grazing intensities, such as 12%, minor disturbances occur in soil microbial biomass compared to other intensities, emit less CO2 into the atmosphere for each animal unit produced. The levels of organic matter and soil microbial biomass systems are lower in grazed than in areas excluded from grazing for a long period. [ABSTRACT FROM AUTHOR]