The search for improved productivity of livestock has stimulated deforestation of forested areas in the Pantanal for pasture planting, raising concerns about the sustainability of the natural resources. To study some aspects of land use in the Pantanal of Mato Grosso, Brazil, this study aimed to evaluate the changes in chemical and physical soil properties due to the conversion of native tree vegetation in pasture, and the exposure of native pasture to a continuous grazing system. The environments of the […]

Non-symbiotic diazotrophic bacteria (NSDB) influence plant growth through biological nitrogen fixation and also production and release of plant growth-regulating substances. The aim of this study was to evaluate the density and phenotypic diversity of this bacterial group in fragments of the “Reserva Biológica Serra dos Toledos” and surroundings, in Itajubá/MG. This reserve is located in the environmental protection area of Mantiqueira and represents an important recharge area and shelter for endemic flora and fauna. Topsoil samples were collected in areas […]

Soil compaction is one of the processes responsible for soil physical degradation that may result in the loss of sustainability of agricultural production. Therefore, it is important to have instrumental strategies to quantify soil physical properties that are influenced by soil compression and used to assess soil quality. The objectives of this study were to: (i) develop an inexpensive pneumatic consolidometer, (ii) evaluate its functionality by the study of the compressive behaviour of a sandy clay Rhodic Hapludox under no-tillage, […]

Winter cover crops are sources of C and N in flooded rice production systems, but very little is known about the effect of crop residue management and quality on soil methane (CH4) and nitrous oxide (N2O) emissions. This study was conducted in pots in a greenhouse to evaluate the influence of crop residue management (incorporated into the soil or left on the soil surface) and the type of cover-crop residues (ryegrass and serradella) on CH4 and N2O emissions from a […]

Balanced fertilization is important for plant growth. There is little information on physic nut (Jatropha curcas L.) and tests with the fertilization of the species are very recent. This study evaluated the initial growth of physic nut seedlings in response to NPK rates to Quartzarenic Neossol in a greenhouse and estimated P and K critical soil levels and N, P and K in shoot dry matter after 120 days of evaluation. The treatments were arranged in a randomized, fractional factorial […]

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 […]