The ion exchange resin method used in some laboratories in Brazil requires soil grinding for the determination of available P. As a consequence of grinding, the extraction of internal labile P in aggregates is expected, increasing the concentration of available-P. On the other hand, finer grinding increases the exposure of soil particle surface, which creates additional sites for further P adsorption. The aim of this study was to evaluate extraction efficiency available-P by Mehlich-1, and anion exchange resin in beads […]

The reliability of soil analysis depends on the correlation of nutrient concentration in the soil obtained by a given method with the plant nutrient uptake. The objective of this study was to evaluate the correlations between phosphorus content estimated by different methods and phosphorus quantity absorbed by rice plants in some flooded soils from Rio Grande do Sul state (RS), Brazil. Soil samples from 16 locations in RS, largely different in soil chemical and physical properties, were collected from the […]

The measures of the average and variability of soil fertility indexes can vary with the sampling tool and soil tillage type. Soil sampling methods must be developed that are more reliable to represent the real conditions of soil fertility. This study aimed at an evaluation of the effects of the cutting shovel and hand auger on measures of average and variability of the soil fertility index (a) under no-tillage (NT) and conventional tillage (CT), (b) to estimate the minimum number […]

The use of pre-mixed nitric and hydrofluoric acids for the decomposition of samples containing high amounts of Si can cause the precipitation of Al(III), Ca(II), Fe(III), and Mg(II) fluorides during digestion, reducing the total recovery of these elements. Four procedures were applied to certified soil samples in an attempt to circumvent this problem. The most efficient procedure was based on microwave-assisted acid digestion decomposition of the samples, followed by separation of the residual silicate compounds. This fraction was solubilized using […]

Pot experiments are being used to study the potassium supplying capacity of soils. A greenhouse experiment with this objective evaluated samples of two Planosols, a Chernosol and a Gleisol, where flooded rice did not respond to potassium fertilization. The soils were cropped during 50 days with rice (Oriza sativa – BR-IRGA 409). Potassium uptake by the plant shoot, the exchangeable and non-exchangeable soil K, extracted by NH4OAc 1 mol L-1 and boiling HNO3 1 mol L-1, respectively, were evaluated, before […]

Conflicting results have been achieved by the evaluation of manganese availability in soil, largely a consequence of varying values denoted as available by different extractants. Knowledge on the element’s chemical forms in the soil and on relationships with the available concentrations are important to predict its behavior in the soil-plant system. In this study, six Oxisol soil samples were analyzed to evaluate the influence of liming and different manganese doses on desorption, extraction and fractioning. These soil samples, with and […]

Knowledge of the chemical forms of Zn in the soil and the relationships with soil available concentrations are important for predicting its behavior. This work aimed to study the influence of zinc on the desorption, extraction and fractioning of Zn in samples from six Oxisols. The soil samples, with and without lime application, were kept incubated for 30 days after receiving Zn doses (0.0, 20, and 40 mg dm-3). After incubation, the micronutrient was extracted with Mehlich-1, Mehlich-3, DTPA and […]

This study was carried out at EMBRAPA-CNPAF, Santo Antônio de Goiás (GO), Brazil, in a clayey Oxisol, under three soil tillage systems, from 1992 to 1998.Corn was grown in the summer and common bean in the winter, under center pivot sprinkler irrigation.The objective was to compare the values of pH, Ca, Mg, P, and K of the soil, sampled at different depths under no-tillage to those from soil under moldboard plough tillage (conventional) and harrow tillage.Forty replicates were collected at […]

Procedures based on modifications of chemical properties are potentially useful for mitigating phytotoxicity of heavy metals in soils. However, it is difficult to predict the effects of different ameliorating agents on the bioavailability of heavy metals in soil simultaneously contaminated with several metals. This study was developed in a soil from a dumping site of a zinc extraction and manufacturing industry-Companhia Mineira de Metais-CMM, located at Três Marias (MG), to assess content, fractioning and bioavailability of Zn, Cd, Cu and […]

The aim of this work was to study the extraction of available boron using hot water and CaCl2 5 mmol L-1, and a microwave oven as the heating device. Boron was determined using azomethine-H. The influence of some soil characteristics on the performance of the extractants, was also studied. Corn plants were grown in a greenhouse, in a completely randomized block design, using 17 soil types and 6 B rates (0.0, 0.15, 0.30, 0.60, 0.90 and 1.5 mg dm-3) in a factorial with three […]