ABSTRACT To reduce acidity in no-till systems, lime is broadcast on the soil surface without incorporation. Two experiments were carried out, one in a clayey Latossolo Vermelho Distrófico (Rhodic Hapludox) and another in a sandy loam Neossolo Litólico Húmico (Lithic Hapludoll), to test the hypothesis that the source and particle size of lime influence soil reaction in the short term, and crop response to surface liming under a no-till system. A randomized complete block design was used in a 2 […]

Birdsfoot trefoil is a perennial winter-spring forage legume, highly important in Rio Grande do Sul, in the south of Brazil. It stands out for the ability to survive in relatively acidic and nutrient-poor soils. This study aimed to select birdsfoot trefoil rhizobial strains with tolerance to acidity and aluminum toxicity and efficiency in nitrogen fixation in nutrient-poor soils. Fifty-two isolates of Lotus spp rhizobia from soils of five locations in the state of Rio Grande do Sul were evaluated. The […]

The recent shift in soil tillage from conventional to no-tillage systems in Brazil alters the soil system dynamics. In soils cultivated under the no-tillage system the relations are established and preserved over the course of time, which increases the functional complexity of the system, while under the conventional system often destroys these relationships. Some questions have risen about the reliability of sampling the so-called “arable soil layer” (0-20 cm) for soil acidity quantification in the no-tillage system due to the […]

Intensive land use can change the chemical composition of the soil solution and cause solute losses. Thus, it can alter the chemical composition of water courses. A study was carried out in a farm of EPAMIG in Oratorios, state of Minas Gerais, Brazil, from June 1996 to May 1997, to evaluate the effect of soil management on the chemical composition of soil solution, taking climatic conditions into consideration. Soluble organic carbon was also determined in the soil solution and in […]

Lime application on the soil surface in no-tillage systems, without incorporation, has not been effective in certain edaphic and climatic conditions for the correction of acidity or for calcium and magnesium supply to plants. Searching alternatives for limestone application without the conventional tilling and harrowing operations, this study tried to evaluate the efficiency of different lime application forms for the chemical soil attributes, nutritional state, and agronomic characteristics of corn crop. A randomized block design with split-plots and three replications […]

The effects of superficial lime application on chemical soil characteristics in no-tillage systems and its influence on root growth and mineral nutrition in maize crops has not been thoroughly investigated yet. To evaluate these effects on maize (hybrid AG 9090) and its reflexes on the grain yield performance under no-tillage, a field trial was carried out on a dystrophic Red Latosol (Hapludox) in Ponta Grossa, State of Paraná, Brazil. A completely randomized block design with three replications was used in […]

The determination of soil potential acidity (H + Al) extracted by the 0.5 mol L-1 calcium acetate solution is a routine analysis in Brazilian soil laboratories. However, due to analytical facilities, it is becoming a regular procedure to estimate the values of potential acidity using the equilibrium pH of the soil suspension with the SMP solution. The aim of this study was to look at the relationship between pH SMP and H + Al in soils of Pernambuco, in order […]

The aim of this study was to select and partially characterize efficient nitrogen-fixing rhizobia associated to pigeonpea from coastal tableland areas in the Northeast of Brazil. Sixteen rhizobia from different coastal tableland areas were evaluated under greenhouse condition, at the Embrapa Coastal Tablelands (Aracaju, Sergipe, Brazil). Four isolates performed better than the others in relation to shoot N content (NC), shoot dry weight (SDW), leaf area (LA) and nodule dry weight (NDW). NDW showed high correlation with SDW, LA and […]

This study was conducted to examine the distribution and nature of Fe oxides in plinthic soils on the sediments of Barreiras Group (in the state of Piauí) and Itapecuru Formation (in the state of Maranhão) in Northeastern Brazil. Four pedons were selected: a “plinthic, dystrophic, epieutrophic Gray Podzolic with low activity clay” and a “dystrophic Plinthosol with low activity clay” (both Plinthic Kandiustalfs) on the Barreiras sediments, as well as an “eutrophic Plinthosol with low activity clay” and an “allic […]

The determination of the cation exchange capacity (CEC) and the relative fractions occupied by the most common cations is crucial for soil chemical characterization and soil fertility diagnostic. These variables and the exchangeable Al3+, Ca2+ and Mg2+ concentrations have been determined in the routine soil analysis by official laboratories in the States of Rio Grande do Sul and Santa Catarina since 1994. The relationship between the SMP index and the H + Al value (potential acidity) was studied in order to establish […]