Determination of reactivity rates of silicate particle-size fractions

The efficiency of sources used for soil acidity correction depends on reactivity rate (RR) and neutralization power (NP), indicated by effective calcium carbonate (ECC). Few studies establish relative efficiency of reactivity (RER) for silicate particle-size fractions, therefore, the RER applied for lime are used. This study aimed to evaluate the reactivity of silicate materials affected by particle size throughout incubation periods in comparison to lime, and to calculate the RER for silicate particle-size fractions. Six correction sources were evaluated: three slags from distinct origins, dolomitic and calcitic lime separated into four particle-size fractions (2, 0.84, 0.30 and <0.30-mm sieves), and wollastonite, as an additional treatment. The treatments were applied to three soils with different texture classes. The dose of neutralizing material (calcium and magnesium oxides) was applied at equal quantities, and the only variation was the particle-size material. After a 90-day incubation period, the RER was calculated for each particle-size fraction, as well as the RR and ECC of each source. The neutralization of soil acidity of the same particle-size fraction for different sources showed distinct solubility and a distinct reaction between silicates and lime. The RER for slag were higher than the limits established by Brazilian legislation, indicating that the method used for limes should not be used for the slags studied here.

Yield and mineral nutrition of soybean, maize, and Congo signal grass as affected by limestone and slag

The objective of this work was to evaluate the efficiency of superficial application of limestone and slag, and their effects on soil chemical attributes and on yield and mineral nutrition of soybean, maize, and Congo signal grass (Urochloa ruziziensis). The experiment was carried out in a Rhodic Hapludox under no tillage system. The treatments consisted of the use of limestone or slag (silicates of calcium and magnesium) to correct soil acidity, and of a control treatment without the use of soil correctives. Rates were calculated in order to raise soil base saturation up to 70%. Soybean was sown in November 2006 and maize in December 2007. Congo signal grass was sown right after the harvests of soybean and maize, and it was cropped during the off-seasons. Soil chemical attributes were evaluated at 6, 12, and 18 months after the application of the corrective materials. Slag is an efficient source for soil acidity correction, being able to raise the exchangeable base levels in the soil profile faster than lime. Both limestone and slag increase dry matter yield of Congo signal grass, and grain yield of soybean and maize. Slag is more effective in improving maize grain yield.

Caracterização e classificação quanto ao risco ambiental do estéril da mina de cromita do município de Andorinha, Bahia

The mineral waste studied was host rock from a chromite mine located in Andorinha/Bahia, extracted and stockpiled in yards without specific application. Host rock was submitted to chemical analysis, XRD, SEM-EDS, IR and TGA and classified according to ABNT standards for solid waste classification. Analyses confirmed that this host rock, classified as ultrabasic, consists mainly of dolomite, calcite and diopside. Hazard assessment results showed this host rock should be classified as class II B - inert waste, important for its potential application in agriculture as a soil acidity correction agent.

Aplicação superficial de calcário e diferentes resíduos em soja cultivada no sistema plantio direto

A prática da correção da acidez do solo pela aplicação superficial de corretivos sobre a palha no sistema plantio direto se restringe ao calcário, não havendo maiores estudos em relação à escória de aciaria, lama cal e lodo de esgoto centrifugado. O objetivo do trabalho foi avaliar os índices de acidez do solo e a produtividade da soja em função da aplicação superficial de lodo de esgoto centrifugado, lama cal, escória de aciaria e calcário dolomítico. O trabalho foi desenvolvido em Latossolo Vermelho distrófico, durante os anos agrícolas de 2002 a 2005, sob sistema plantio direto. Os tratamentos constituíram da aplicação superficial de escória de aciaria (E), lama cal (Lcal), lodo de esgoto centrifugado (LC), calcário dolomítico e sem aplicação de corretivo, em delineamento em blocos ao acaso, com quatro repetições. A aplicação superficial de escória de aciaria, lama cal e lodo de esgoto centrifugado permite a correção da acidez do solo, o deslocamento do Ca2+, o aumento da saturação por bases e redução do Al3+ até 40 cm, e para o calcário, até 20 cm, fatores que condicionaram o aumento da produtividade da soja para os tratamentos LC, E e Lcal em 2003/2004 e 2004/2005 e para LC e E em 2002/2003 no sistema plantio direto.

Eficiência de escórias de siderurgia na cultura do feijoeiro em sistema de semeadura direta

In the no till system, soil acidity correction practice is restricted to limestone use and there is little information regarding slag. The study aimed to evaluate the amendments in soil chemical properties, yield and bean nutrient uptake according to the application forms of slags, compared to limestone, in the implantation of no till system. The experiment was conducted in the field at College of Agricultural Sciences, Botucatu (SP) from December 2010 to May2011. The treatments consisted of two application ways of seven soil acidity correctives: steel slag, blast furnace slag, ladle furnace slag, stainless steel slag (agrosilício), wollastonite, lime and calcined dolomite lime, plus one control without corrective application. Each material dose was calculated to raise the base saturation to 70%. Soil acidity was neutralized down to 20cm with limestones, whereas for wollastonite and ladle furnace slag those effects occurred down to 10cm, for steel slag, blast furnace slag and agrosilício the corrective effect was restricted to the first 5cm. The bean yield increased by application of correctives in soil acidity, without differences between the application ways.

Yield and mineral nutrition of soybean, maize, and congo signal grass as affected by limestone and slag

The objective of this work was to evaluate the efficiency of superficial applicationof limestone and slag, and their effects on soil chemical attributes and on yield and mineral nutrition of soybean, maize, and Congo signal grass (Urochloa ruziziensis). The experiment was carried out in a Rhodic Hapludox under no tillage system. The treatments consisted of the use of limestone or slag (silicates of calcium and magnesium) to correct soilacidity, and of a control treatment without the use of soil correctives. Rates were calculated in order to raise soil base saturation up to 70%. Soybean was sown in November 2006and maize in December 2007. Congo signal grass was sown right after the harvests of soybean and maize, and it was cropped during the offseasons. Soil chemical attributes were evaluated at 6, 12, and 18 months after the application of the corrective materials. Slag isan efficient source for soil acidity correction, being able to raise the exchangeable base levels in the soil profile faster than lime. Both limestone and slag increase dry matter yield of Congo signal grass, and grain yield of soybean and maize. Slag is more effective in improving maize grain yield.

Avaliação de eficiência relativa para a reatividade em silicatos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Resposta de plantas de cobertura a doses de silício e estresse hídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atributos do solo decorrentes dos sistemas de produção e da aplicação superficial de corretivos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Combinações de gesso, silicato e calcário aplicados superficialmente no sistema plantio direto de arroz e feijão irrigados por aspersão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de sistemas de produção e aplicação superficial de corretivos em plantio direto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of reactivity rates of silicate particle-size fractions

The efficiency of sources used for soil acidity correction depends on reactivity rate (RR) and neutralization power (NP), indicated by effective calcium carbonate (ECC). Few studies establish relative efficiency of reactivity (RER) for silicate particle-size fractions, therefore, the RER applied for lime are used. This study aimed to evaluate the reactivity of silicate materials affected by particle size throughout incubation periods in comparison to lime, and to calculate the RER for silicate particle-size fractions. Six correction sources were evaluated: three slags from distinct origins, dolomitic and calcitic lime separated into four particle-size fractions (2, 0.84, 0.30 and <0.30-mm sieves), and wollastonite, as an additional treatment. The treatments were applied to three soils with different texture classes. The dose of neutralizing material (calcium and magnesium oxides) was applied at equal quantities, and the only variation was the particle-size material. After a 90-day incubation period, the RER was calculated for each particle-size fraction, as well as the RR and ECC of each source. The neutralization of soil acidity of the same particle-size fraction for different sources showed distinct solubility and a distinct reaction between silicates and lime. The RER for slag were higher than the limits established by Brazilian legislation, indicating that the method used for limes should not be used for the slags studied here.

Aplicação de corretivos de acidez do solo na implantação do sistema plantio direto

Pós-graduação em Agronomia (Agricultura) - FCA

Effects of surface application of dolomitic limestone and calcium-magnesium silicate on soybean and maize in rotation with green manure in a tropical region

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Emissão de gases do efeito estufa e estoque de carbono no sistema solo-planta em área com aplicação superficial de calcário e gesso em experimento de longa duração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)