The monitoring of soil quality based on physical properties is important for the evaluation and maintenance of the sustainability of agricultural systems. An indicator property of soil quality should be sensitive to management changes. This study aimed to evaluate the S parameter as an indicator of soil physical quality and aggregation of an Oxisol, managed for 11 years in systems with and without the inclusion of off-season cover crops. The treatments consisted of: conventional system (SC) and conservation systems with […]

Soil functions and quality are closely linked to soil structure. The effect of management practices on the recovery of the aggregation of a physically degraded soil was studied based on the distribution of water-stable aggregates and single particles (diameter classes 9.51-4.76, 4.76-2.00, 2.00-0.25, 0.25-0.053, < 0.053 mm) and carbon stock (C) in the surface layer (0-7.5 cm) of a Paleudult in the Central Depression region of the state of Rio Grande do Sul, Brazil, under different management systems. The following […]

The effect of potting mix and phosphate fertilization on the production of rooted cocoa tree cuttings was evaluated and recommended rates and critical foliar P levels were determined based on a factorial 5 x 5 + 1 experiment: five potting medium (coconut fiber CF and Plantmax® mix), five P rates at planting (0 to 800 mg dm-3) and an additional P treatment (applied on the 30th day). Each plot contained 27 cuttings, of which 12 rooted cuttings were evaluated. From […]

Detailed studies on hydrology and sediment production are of great value to enhance the understanding and control of the water erosion process, with a view to more continuous and effective soil and water conservation practices. The purpose of this study was to develop specific (for each treatment replication) hydrograms (instantaneous runoff discharge versus time) and sedimentograms (instantaneous sediment concentrations in the runoff and instantaneous soil loss rates versus time), associated with water erosion in a soil under different crop sequences […]

Air permeability (Kα) can be used to assess soil structure changes resulting from different tillage systems. This study tested the hypothesis that the reduced soil disturbance in no-tillage results in continuous pores and better soil aeration conditions. The objective was to evaluate the aeration of a Rhodic Hapludox under conventional tillage (CT) and no-tillage (NT), based on soil air permeability (Kα), air-filled porosity (εa) and indices of pore continuity (K1 and N). Eighty undisturbed soil cores (2 treatments x 2 […]

Nutrient cycling and balance in integrated crop-livestock systems (ICL) are processes that involves soil, plant and animal components, beyond fertilization. Animal management, by modifying soil biotic and abiotic conditions, also influences this process as it affects the residue decomposition rate. The objective was to evaluate potassium (K) cycling and balance in an ICL system with grazing (black oat and ryegrass) intensities in the winter, followed by soybean cultivated in the summer. The experiment was conducted as of May of 2001 […]

The conversion of native forests by cutting and burning into farming areas leads to alterations in the dynamics of soil organic matter, with changes in emissions of greenhouse gases (GHGs: CO2, CH4 and N2O) from the biosphere to the atmosphere. These cause an average temperature rise and, consequently, global climate change. The aim of this study was to examine relationships between the fluxes of CO2, CH4 and N2O with moisture, microbial biomass and inorganic N forms in soil with different […]

More effective methodologies to determine the soil class distribution must be evaluated in order to meet the demand for soil maps at regional and global scales. In this study, logistic regressions were used as predictive models in an application of Digital Soil Mapping. The models were derived from an existing soil map as dependent variable and terrain attributes as independent variables. The probability of finding soil classes in the landscape at the 1st and 2nd Categorical Level of the Brazilian […]

Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 […]

Statistical models allow the representation of data sets and the estimation and/or prediction of the behavior of a given variable through its interaction with the other variables involved in a phenomenon. Among other different statistical models, are the autoregressive state-space models (ARSS) and the linear regression models (LR), which allow the quantification of the relationships among soil-plant-atmosphere system variables. To compare the quality of the ARSS and LR models for the modeling of the relationships between soybean yield and soil […]