Biological and microbiological attributes in Oxisol managed with cover crops

Abstract

The inclusion of winter cover crops and fertilization with nitrogen to the soil can have an effect on their biological and microbiological attributes. The aim of this study was to evaluate biological and microbiological attributes in soil under different winter cover crops and nitrogen doses. The experiment was conducted at the Frederico Westphalen-RS campus of the Federal University of Santa Maria (UFSM) in a Rhodic Hapludox soil. The experimental design was a randomized block in factorial arrangement (2 x 10): 10 winter cover crops systems (Fallow [control], black oats, white oats, ryegrass, forage turnip, vetch, white lupine; black oat + forage turnip; black oat + vetch and black oat + vetch + fodder turnip), and two nitrogen rates in the form of urea applied in successive crops of beans common and maize, with four replications. We assessed the biological attributes (Margalef’s richness, Simpson’s dominance, Shannon’s diversity and abundance of organisms) and microbiological (carbon and nitrogen microbial biomass, basal respiration, metabolic quotient and microbial quotient of the soil). The fallow with wild species and white lupine showed greater Simpson’s dominance and abundance of organisms due to the increase in the number of individuals of the order Collembola. Vetch improved the biological attributes of the soil with increase in Collembola abundance and diversity of organisms of soil fauna. The application of nitrogen favored the microbial biomass carbon and reduced the metabolic quotient.