ABSTRACT Mehlich-1 soil extract is currently used in Rio Grande do Sul (RS) and Santa Catarina (SC) States, in Brazil, to evaluate soil phosphorus available to plants and Mehlich-1 is sensitive to soil buffering capacity. This limitation is overcome partly by soil separation into buffering classes based on soil clay content. However, soil clay content has some technical and operational limitations, such as the underestimation of soil clay levels in soils under no-till. The aim of this study was to […]

In Brazil, along with the expansion of clonal forestry, the management of more productive and more nutrient-demanding genotypes has led to the appearance of micronutrient deficiency symptoms, mainly of boron (B), and more recently, of copper (Cu) and of zinc (Zn), especially in Cerrado areas. The purpose of this study was to evaluate three extraction solutions to determine Zn availability (Mehlich-1, Mehlich-3 and DTPA pH 7.3) for eucalyptus seedlings grown in a greenhouse, on six Cerrado soil samples, and to […]

The deficiency or excess of micronutrients has been determined by analyses of soil and plant tissue. In Brazil, the lack of studies that would define and standardize extraction and determination methods, as well as lack of correlation and calibration studies, makes it difficult to establish limits of concentration classes for analysis interpretation and fertilizer recommendations for crops. A specific extractor for soil analysis is sometimes chosen due to the ease of use in the laboratory and not in view of […]

Multielement soil extractant solutions are used by several soil testing laboratories to determine the plant availability of several nutrients by the same extractant, to decrease costs and labor. The Mehlich-1 (M1) and Mehlich-3 (M3) solutions are often used for this purpose. In this study, they were used to evaluate soil P availability using 360 soil samples of the State of Rio Grande do Sul (Southern Brazil). The correlation coefficients between the P concentrations extracted by these solutions were strongly associated […]

The change of cultivation systems from conventional to no-tillage, the change in soil sampling depth and the higher crop yields over time can influence the critical P content, fertility ranges and fertilizer doses recommended for crops. The objective of this work was to calibrate the soil P tests, Mehlich-1, Mehlich-3 and anion-exchange (AER) resin for soybean, wheat and corn plants cultivated under no-tillage system, and to estimate the P fertilizer amounts for a maximum economic yield. For this purpose soil […]

The objective of this research was to evaluate a modified ion exchange resin method for Mn and Fe extraction from soils. Forty-four soil samples presenting low, medium, and high Mn and medium to high Fe concentrations were used. Maize and soybeans plants were grown as test plants in a pot experiment in a greenhouse. Soil samples were analyzed for Mn and Fe using the modified ion exchange resin, DTPA, AB-DTPA, Mehlich-1, and Mehlich-3 methods. The correlation coefficients between soil Mn […]

The effects of soil physical and chemical properties related to the soil Phosphorus Buffering Capacity (PBC) on soil P critical levels, by Mehlich-1, Mehlich-3, and Bray-1 extractant solutions were studied in six soil samples of the State of Pernambuco and in plant shoot, for the cultivation of Brachiaria brizantha (Hoscht ex A. Rich.) Stapf. cv. Marandu. This research was carried out under greenhouse conditions with surface soil samples with different clay contents, to which P doses, defined by the soil solution […]

The determination of potentially available phosphorus by chemical extractors is difficult in variable charge soils because there are several degrees of bound energy between phosphorus and colloids. The objective of this work was to estimate the minimum number of successive extractions with the Mehlich-1, Mehlich-3 and anion exchange resin (AER) methods to obtain values of potentially available phosphorus. Thirteen successive extractions were accomplished with Mehlich-1, Mehlich-3 and AER methods in samples of a Rhodic Hapludox under a no-tillage system and […]

Heavy metal components in solid urban waste composts have been one of the main causes of concern in relation to its use on agricultural soils. On this background, a field experiment was carried out to study the effects of successive compost application on Cd, Cr, Cu, Ni, Pb, and Zn contents in a Typic Hapludox, in sugarcane plants, as well as on the phytoavailability of these metals as assessed by chemical extractors (DTPA, 0,1 mol L-1 HCl and Mehlich-3). The […]

Aiming to evaluate the phosphorus availability in five Amazonian soil samples, amended with different phosphates, a pot trial was carried out under greenhouse conditions at the Centro de Energia Nuclear na Agricultura, Piracicaba (SP,Brazil), from october, 1993 to march, 1994, using the soils: medium texture Yellow Latosol, clayey Yellow Latosol, very clayey Yellow Latosol, clayey Red-Yellow Podzolic and very clayey Red-Yellow Podzolic. Four phosphate sources were applied (triple superphosphate, fine yoorin thermophosphate, granular yoorin thermophosphate and North Caroline rock phosphate) […]