In this study, a first order exponential model was adjusted to the experimental data of soil organic carbon (OC) and total nitrogen (TN) of a 9-year-old experiment in southern Brazil. Parameters of soil organic matter dynamics were determined and the soil OC and TN stocks simulated in a Paleudult soil under three tillage systems (conventional tillage: CT, reduced tillage:RT, and no-tillage:NT) and three cropping systems (oat/maize-O/M, oat + vetch/maize-O + V/M and oat + vetch/maize + cowpea-O + V/M + […]

Soil management systems, with different degrees of soil mobilization and different plant residue composition, alter soil biological properties, with consequences in soil quality and in plant productivity. In order to measure such alterations, soil microbial biomass and its activity were evaluated in a Paleudult soil, in the Central Depression of Rio Grande do Sul state, Brazil, conducted under different soil management systems, in a long-term experiment, for 12 years. Soil samples were collected in four different times, during 12 months, […]

Organic matter is considered the soil attribute most sensitive to the changes triggered by the management systems. The objective of this study was to evaluate the effect of nine years using three soil tillage systems -conventional tillage, reduced tillage and no tillage- on soil chemical characteristics of a Humic Cambisol in southern Brazil. Soil samples were collected in September 1996 at depths of 0-2, 2-5, 5-10, 10-15, and 15-20 cm, and analysed for C and N contents in total organic […]

The study of root distribution in soils is an adequate method to detect adverse conditions to root development, and evaluate the effect of soil alterations caused by soil management systems. With these objectives, a field experiment was carried out for five years on a Paleudult soil with oat + clover/maize under conventional tillage, reduced tillage and no tillage. To observe the structural modifications of the soil, an adaptation of the “profil cultural” method, was used along with the determination of […]

The best measures of crop residue quality for soil protection against erosion are the percentage of soil cover and its persistence on the soil surface. These two variables, in turn, may be strongly affected by soil tillage. This study was carried out in Rio Grande do Sul State, Southern Brazil (30°06’S; 51°39’W). Crop residue mulch persistence was evaluated over a fallow period, following the harvest of a soybean crop. Three conservation tillage methods (chiseling, disking, and no-till) were used as […]

The aim of this experiment was to evaluate the nitrogen of the microbial biomass under different soil management systems by the fumigation-incubation (FI) and fumigation-extraction (FE) methods. Soil samples were collected in four seasons, during one year, from a Paleudult soil in the Central Depression of Rio Grande do Sul State, Brazil. Soil microbial biomass N was analyzed in soil under three tillages systems (conventional, reduced and direct drilling) and two crop systems: oats (Avena strigosa) + vetch (Vicia sativa)/corn […]