Suscetibilidade magnética e cor na predição do fósforo adsorvido e metais pesados em áreas sob transição basalto-arenito
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Data
2021-03-05
Autores
Chitlhango, Angelina Pedro
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Em regiões tropicais e subtropicais, os solos são caracterizados pelo Intemperismo avançado com maior concentração de óxidos de ferro. A afinidade dos óxidos de ferro aos fosfatos e a capacidade de retenção dos metais pesados do solo, é um dos fatores limitantes na produção agrícola. Portanto, o conhecimento dos mecanismos e o grau das interações da mineralogia e dos atributos do solo, pode fornecer estratégias na implementação de métodos como o uso da cor e suscetibilidade magnética dos solos, como ferramentas promissoras no mapeamento das zonas mínimas de manejo agrícola, reduzindo os custos de produção agrícola. O presente estudo teve como objetivos: I) Avaliar a eficiência da cor e da suscetibilidade magnética no mapeamento do fósforo adsorvido (Pads) em solos basalto-arenito. II) Avaliar apossibilidade de predizer metais pesados do solo (Cr, Mn, Ni, Zn e Zr) para fins de mapeamento do solo sob basalto-arenito por meio da suscetibilidade magnética.O estudo foi realizado na Fazenda de Ensino, Pesquisa e Produçãoper-tencente ao Campus da UNESP/ FCAV, numa área de aproximadamente 628,9ha, localizada no município de Jaboticabal no Estado de São Paulo, inserida na provín-cia geomorfológica do Planalto Ocidental Paulista, sendo uma área de transição basalto-arenito. Foram coletadas amostras de solo no total de 70 pontos, na camada superficial (0,00 – 0,20 m) de profundidade. A suscetibilidade magnética em baixa frequência e em alta frequência foi determinada em todas as amostras. Para obten-ção de resultados mais precisos usou-se a suscetibilidade em baixa frequência, mais sensível a minerais magnéticos e o índice de avermelhamento foram analisados e comparados com alguns atributos químicos, físicos e mineralógicos do solo. A quantificação dos metais pesados utilizou-se o método espectrômetro de fluorescência de raios–X. Os dados foram submetidos à análise estatística clássica e geoestatística para avaliar a variabilidade e a dependência espacial dos atributos estudados com base na variação geológica. A suscetibilidade magnética em baixa frequência e o índice de avermelhamento se correlacionaram com o Pads (r = 0,74; P< 0,01) e (r = 0,4; P< 0,01), respectivamente. A suscetibilidade magnética em baixa frequência correlacionou-se significativamente com Cr (r=-0,61; p < 0,01), Mn (r = 0,88; p < 0,01), Ni, (r = 0,75; p < 0,01), Zn (r = 0,30; p < 0,01) e Zr (r = 0,87; p < 0,01), o que permite seu uso como componente de funções de pedotransferência para quantificação indireta de metais pesados do solo. A suscetibilidade magnética foi o melhorpreditor do Pads e dos metais pesados do solo.
In tropical and subtropical regions, soils are characterized by advanced weathering with a higher concentration of iron oxides. The affinity of iron oxides to phosphates and the capacity to retain heavy metals in the soil is one of the limiting factors in agricultural production. Therefore, the knowledge of the mechanisms and the degree of interactions of mineralogy and soil attributes can provide strategies for the implementation of methods such as the use of color and magnetic susceptibility of soils, as promising tools in the mapping of minimum zones for agricultural management, reducing agricultural production costs. The present study aimed to: I) evaluate the efficiency of color and magnetic susceptibility in the mapping of adsorbed phosphorus (Pads) in basalt-sandstone soils. II) Evaluate the possibility of predicting soil heavy metals (Cr, Mn, Ni, Zn and Zr) for soil mapping purposes under basalt-sandstone through magnetic susceptibility. The study was carried out at the Teaching, Research and Production Farm belonging to the UNESP/FCAV Campus, in an area of approximately 628.9 ha, located in the municipality of Jaboticabal in the state of São Paulo, Brazil, inserted in the geomorphological province of Planalto Western Paulista, being a basalt-sandstone transition area. Soil samples were collected from a total of 70 points, in the surface layer (0.00 – 0.20 m) deep. Low frequency and high frequency magnetic susceptibility was determined in all samples. To obtain more accurate results, the susceptibility in low frequency, more sensitive to magnetic minerals, and the redness index were analyzed and compared with some chemical, physical and mineralogical soil attributes. The quantification of heavy metals was performed using the X-ray fluorescence spectrometer method. The data were submitted to classical statistical and geostatistical analysis to assess the variability and spatial dependence of the studied attributes based on geological variation. Low frequency magnetic susceptibility and redness index correlated with Pads (r = 0.74; P< 0.01) and (r = 0.4; P< 0.01), respectively. Low frequency magnetic susceptibility correlated significantly with Cr (r=-0.61; p<0.01), Mn (r=0.88; p<0.01), Ni, (r=0.75; p < 0.01), Zn (r = 0.30; p < 0.01) and Zr (r = 0.87; p < 0.01), which allows its use as a component of pedotransfer functions for quantification indirect heavy metals from the soil. Magnetic susceptibility was the best predictor of Pads and soil heavy metals.
In tropical and subtropical regions, soils are characterized by advanced weathering with a higher concentration of iron oxides. The affinity of iron oxides to phosphates and the capacity to retain heavy metals in the soil is one of the limiting factors in agricultural production. Therefore, the knowledge of the mechanisms and the degree of interactions of mineralogy and soil attributes can provide strategies for the implementation of methods such as the use of color and magnetic susceptibility of soils, as promising tools in the mapping of minimum zones for agricultural management, reducing agricultural production costs. The present study aimed to: I) evaluate the efficiency of color and magnetic susceptibility in the mapping of adsorbed phosphorus (Pads) in basalt-sandstone soils. II) Evaluate the possibility of predicting soil heavy metals (Cr, Mn, Ni, Zn and Zr) for soil mapping purposes under basalt-sandstone through magnetic susceptibility. The study was carried out at the Teaching, Research and Production Farm belonging to the UNESP/FCAV Campus, in an area of approximately 628.9 ha, located in the municipality of Jaboticabal in the state of São Paulo, Brazil, inserted in the geomorphological province of Planalto Western Paulista, being a basalt-sandstone transition area. Soil samples were collected from a total of 70 points, in the surface layer (0.00 – 0.20 m) deep. Low frequency and high frequency magnetic susceptibility was determined in all samples. To obtain more accurate results, the susceptibility in low frequency, more sensitive to magnetic minerals, and the redness index were analyzed and compared with some chemical, physical and mineralogical soil attributes. The quantification of heavy metals was performed using the X-ray fluorescence spectrometer method. The data were submitted to classical statistical and geostatistical analysis to assess the variability and spatial dependence of the studied attributes based on geological variation. Low frequency magnetic susceptibility and redness index correlated with Pads (r = 0.74; P< 0.01) and (r = 0.4; P< 0.01), respectively. Low frequency magnetic susceptibility correlated significantly with Cr (r=-0.61; p<0.01), Mn (r=0.88; p<0.01), Ni, (r=0.75; p < 0.01), Zn (r = 0.30; p < 0.01) and Zr (r = 0.87; p < 0.01), which allows its use as a component of pedotransfer functions for quantification indirect heavy metals from the soil. Magnetic susceptibility was the best predictor of Pads and soil heavy metals.
Descrição
Palavras-chave
Fosfatos, Minerais de argila, Mineralogia do solo, Óxidos de ferro, Pedologia, Phosphates, Clay minerals