Resumo -A preocupação com metais pesados provenientes de fertilizantes minerais deve-se à possibilidade de entrada desses elementos na cadeia alimentar. O objetivo deste trabalho foi determinar o teor de metais pesados e comparar três métodos de extração (Embrapa, USEPA 3051A e USEPA 3050B) de Cd, Cr, Cu, Ni, Pb e Zn em fosfatos de rochas nacionais e importados. A quantificação dos teores desses elementos foi feita em espectrofotômetro de absorção atômica de chama ar-acetileno. Entre os fosfatos estudados, o termofosfato apresentou concentrações significativamente superiores de Cr, Cu, Ni e Zn e o fosfato natural 2, de Cu, Ni, Pb e Zn. O fosfato reativo 3 apresentou a maior quantidade de Cd (145±13 mg kg ). Os métodos avaliados podem ser aplicados em estudos de teor de metais pesados em fertilizantes fosfatados.Termos para indexação: concentração, extração, metais pesados, fertilizantes. Determination of cadmium, copper, chromium, nickel, lead and zinc in rock phosphatesAbstract -The possibility of food chain transfer is a matter of concern on studies related to heavy metals in mineral fertilizers. The objective of this paper was to determine the content of heavy methods and to compare three extraction procedures (Embrapa, 1999; USEPA 3051A and USEPA 3050B) for Cd, Cr, Cu, Ni, Pb, and Zn in national and imported rock phosphates. The quantification of the trace elements content was performed by airacetylene flame atomic absorption spectroscopy. Among the studied phosphates, the thermophosphate presented significantly greater concentrations of Cd, Cr, Cu, Ni, and Zn whereas Cu, Ni, Pb, and Zn were found in greater contents in the natural phosphate 2. The reactive phosphate 3 presented the greatest quantity of Cd (145±13 mg kg -1) and the natural phosphate 2, the highest quantity of Pb (234±9 mg kg -1). The tested methods can be applied in studies concerning heavy metals in phosphate fertilizers.
RESUMOA fertilidade dos solos das regiões tropicais é limitada pela baixa disponibilidade de fósforo e pela indisponibilização de boa parte do mesmo fornecido na adubação. Ainda existem muitas divergências sobre a melhor forma de utilização das diversas fontes fosfatadas disponíveis no Brasil. Objetivou-se, neste experimento, avaliar a produção de soja, sob a aplicação de diferentes doses e adubos fosfatados em dois tipos de solo. O trabalho foi realizado em casa de vegetação do Departamento de Ciência do Solo da Universidade de Lavras, em vasos de 3 dm 3 . Utilizaram-se dois solos sob cerrado: Neossolo Quartzarênico e Latossolo Vermelho Distroférrico típico. Foram testadas oito fontes (superfosfato triplo-ST, termofosfato magnesiano-TF, quatro fosfatos reativos importados: FR1, FR2, FR3 e FR4 e dois fosfatos naturais nacionais-FN1 e FN2) e quatro doses (0, 100, 300 e 600 mg dm -3 ) de fósforo, utilizando-se a soja como planta-teste. As fontes de solubilidade mais elevada ocasionaram as maiores produções e índices de eficiência em relação aos fosfatos naturais. Os fosfatos naturais importados e o FN2 apresentaram-se mais promissores em fornecer P para a cultura da soja, em relação ao superfosfato triplo, mesmo no primeiro cultivo, principalmente em solo com maior poder tampão de fósforo. A capacidade tampão de fósforo dos solos influenciou a eficiência das fontes de fósforo na cultura da soja.Termos para indexação: Fontes de fósforo, solubilidade de fosfatos, eficiência agronômica. ABSTRACTThe fertility of soils in tropical areas is limited by the low availability of phosphorus as well as by the unavailability of a great proportion of phosphorus supplied with fertilization. There are still some divergences about the best way of using the different sources of phosphorus available in Brazil. The aim of this experiment was to evaluate the soybean production as a result of the application of different phosphorous doses and fertilizers on two types of soils. The work was carried out in a greenhouse at Soil Science Department, Federal University of Lavras, in vases of 3 dm 3 using two kinds of soils: Dystroferric Red Latosol and Quartzarenic Neosols. Eight sources (triple superphosphate-TF, four foreign reactive rock phosphate: FR1, FR2, FR3, and FR4 and two national rock phosphate -FN1 and FN2) and four doses (0, 100, 300, and 600 mg dm -3 ) were applied. Soybeans were used as test plant. Sources with higher solubility showed the highest production and efficiency than natural phosphate. The natural phosphate imported from other countries and FN2 showed good results in supplying P for the soybeans, when compared to the triple superphosphate, even at the first year of culture, mainly on the soil with higher P buffer power. The phosphorus buffer capacity of the soils affected the efficiency of phosphorus sources on the soybean culture. INTRODUÇÃOUm dos fatores responsáveis pela baixa disponibilidade de fósforo (P), nos solos das regiões tropicais, é o fenômeno de fixação do P em reações com componentes do solo, necessi...
Brazil, despite being privileged among other countries, for the amount of fresh water it has, also has many problems with water scarcity, especially in northeastern regions, with high temperatures and frequent periods of drought. As an example, in the late 1990s, the municipality of Aracoiaba experienced a serious crisis of drinking water shortages, which required the construction of the Aracoiaba Dam, which began in 2000. The purpose of this research was to demonstrate the socioeconomic importance of construction from the Aracoiaba Dam, to the communities where it is located, and to the Massif de Baturité. The investigation was developed according to a basic and exploratory nature, with a qualitative and quantitative approach through a case study. Through the surveys carried out, it was found that the Aracoiaba Dam minimized the problem of lack of drinking water in the city, and provided the social and economic development of local communities, neighboring municipalities and also the Metropolitan Region of Fortaleza, through agriculture and livestock, agriculture , horticulture, and other productive activities. The Aracoiaba Dam, develops great socioeconomic importance for this municipality, Maciço de Baturité, and the Metropolitan Region of Fortaleza, which justifies the need for greater inspection and monitoring of production, product and development.
In commercial bananas there is an increasing increase for seedlings of high genetic quality and free of pathogens; thus, the use of micropropagation has been increasingly encouraged for the production of seedlings. However, the success of establishing these seedlings in the environment depends on several factors, in which, the substrate has a relevant role. The objective of this study was to evaluate the growth of micropropagated banana seedlings under the influence of different formulations of substrates based on soil, bovine manure and vegetable ash for organic production system. The experiment was carried out on a certified rural property under an organic production system in the municipality of Palmácia (CE). The experimental design used was completely randomized, with four replications. The substrates were used in a ratio of 2:1, always two parts of soil for one of substrate, which was used: soil (ravine soil), organic compost (bovine manure + vegetal remains), bovine manure and vegetable ash (from sugar cane mill). The test was conducted in full sun and without the aid of irrigation, as the experiment coincided with the rainy season in the region. At 68 days after planting (DAP), growth analyzes were carried out: plant height, diameter of the pseudostem, number of leaves, length of roots, fresh and dry mass of aerial part and roots. The best substrates for the growth of micropropagated banana seedlings cv. Prata Catarina were mixtures of soil + organic compost and soil + manure.
One of the strategies for the recovery of degraded soils is the planting of fast-growing forage species with high biomass production. In this sense, the objective of this research was to evaluate the initial growth of sorghum in degraded soils with organic fertilization and different phosphorus levels. A completely randomized design with a 4 x 3 x 2 factorial arrangement was used, with four soil types, three levels of phosphorus fertilization and two levels of organic fertilization. At 64 days after sowing the characteristics of the initial growth were analyzed: plant height, stem diameter, leaf number and fresh shoot mass. The height was measured by measuring the neck of the plant until the end of the newest fully expanded leaf, measured with the aid of a measuring tape and expressed in centimeters. The diameter of the stem, by means of a digital pachymeter. The application of phosphorus and organic matter in degraded soils is necessary for the initial development of sorghum plants, due to the low availability of this element, caused by the high adsorption of P in the soil colloids. Besides that, the lack of organic matter in the studied soils led to a decrease in the growth of sorghum, therefore, it is concluded that soil management in saline environments is necessary for the application of phosphorus and organic matter for a sustainable and technically viable production.
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