Soil management systems and fertilization types make differentiated amounts of mineral elements in the soil profile available. The objective of this study was to verify alterations in chemical attributes of a Red Latosol (Typic Haplustox) of Brazilian Savannah under organic and mineral fertilization, vegetation cover in no tillage and conventional tillage systems, and with bean and cotton crops. The experiment had a randomized complete block design with split-plots. Two treatments of soil preparation (no tillage and conventional tillage) were installed […]

The study of the spatial variability of soil attributes can help in the determination of a specific management strategy that enhances agricultural productivity. The present study aimed at the evaluation of a possible influence of the soil management on spatial variability of a Dystroferric Red Latosol (Oxisol) physical properties. The study was carried out in 2002, in three adjacent areas, in Lavras, Minas Gerais state, Brazil, with the following management systems: A1 – fallowing for three years; A2 – recently […]

There are few studies on soils under slash-and-burn agriculture in settlements in Amazônia. The aim of this study was the soil characterization in the Apiaú Agricultural Colony, Roraima, and to evaluate changes in some soil chemical properties in function of the management systems and the impacts of burning to the soil properties. The studied areas were: pastures, cultivated with banana and maize, burned forest and natural forest. The samples were submitted to physical chemical and mineralogical analysis. The soils are […]

The presence of straw on soil surface affects K cycling in the production system and can affect soil chemistry by modifying K leaching rate and intensity. An experiment was conducted to evaluate K leaching as affected by 30 mm of simulated rain over pearl millet straw receiving several broadcasted K rates. Pearl millet was grown for 55 days in a green house and then cut at soil level into pieces of 3 to 5 cm. Then it was distributed over the […]

The effect of irrigation on soil C stocks is a result of the balance between the effect of this practice on C input through crop residues and of C losses through microbial decomposition of soil organic matter (SOM). This study aimed at assessing the influence of sprinkler irrigation on SOM dynamics and on the total C stocks in a subtropical Acrisol under no-till (NT) and conventional tillage (CT) in a long-term experiment (8 years). Irrigation increased the C addition (about […]

In Rio Grande do Sul state, the area cultivated with under no-till system now amounts to 60 % of the total rain-fed cultivated area. However, there are still doubts as to crop practices in this soil conservation system, such as liming and fertilization as well as regarding root growth and crop productivity. The objective of this study was to evaluate the effects of lime doses and application forms on corn root development. The experiment was carried out in 1999/2000, in the […]

Soil compaction has led to reduced soybean yields, but the critical bulk density above which the yield decreases are poorly documented. Thus, this work aimed to evaluate the soybean yield (cv. Embrapa 48) in relation to the relative bulk density (Dsr) of a sandy loam (LVd) and a clayey Oxisol (LVef). A greenhouse experiment was carried out in 2001/02 with samples collected at the 0.0-0.2 m layer, sifted through a 4.0 mm sieve, fertilized and compacted in 0.03 m layers in 0.20 high […]

The sorption of herbicides to soil is a process determinant of its dynamics in the environment. For weakly polar compounds such as acetochlor, organic matter represents the main sorbent in soil. The goal of this study was to evaluate the sorption of acetochlor on soil samples, humic acids and humin from an “Argissolo Vermelho distrófico” (PVd-Paleudult) under no-till and conventional tillage systems. Sorption isotherms were carried out at room temperature and the herbicide concentration was determined by high performance liquid […]

The effects of machinery traffic on soil attributes following the adoption of no-till systems in tropical environments are still poorly documented. Numerous questions persist about the dynamic variation of soil structure and its interaction with machinery and equipments. The present study had the objective to evaluate the effect of time of adoption of no-tillage system and compare them to a conventionally tilled soil and a soil under a native forest using soil compressibility models. The evaluated systems were: PD1 (one […]

Soil tillage and crop systems have significant influence on the soil structure, affecting water and air flow. The objective of this study was to evaluate the effects the management has on the soil properties of a Hapludox cultivated with maize intercropped with summer cover crops. Two experiments were carried out in Chapecó, State of Santa Catarina, Brazil under reduced tillage (RT) from 1993 to 1998 and conventional tillage (CT) from 1994 to 1998. Three cropping systems were evaluated under each […]