Estimação de atributos do solo por espectroscopia de reflectância difusa e suscetibilidade magnética no contexto da paisagem
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Data
2016-10-28
Autores
Bahia, Angélica Santos Rabelo de Souza [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente trabalho tem como objetivos: i) caracterizar a mineralogia da fração argila e estudar a variabilidade espacial dos atributos granulométricos, químicos e mineralógicos do solo com base em informações geológicas, pedológicas e geomorfológicas; ii) avaliar o potencial de utilização da espectroscopia de reflectância difusa (ERD) e suscetibilidade magnética (SM) na estimação dos óxidos de ferro hematita (Hm) e goethita (Gt), atributos granulométricos e químicos do solo nos compartimentos da paisagem; iii) utilizar a ERD e a SM no estudo da quantificação e variabilidade espacial da emissão de CO2 do solo (FCO2) e iv) investigar a eficiência da utilização da SM e dos óxidos de ferro em funções de pedotransferência (FPTs) que sejam capazes de estimar a FCO2. A área de estudo, de 870 ha, está localizada no município de Guatapará – São Paulo, e é cultivada com cana-de-açúcar manejada com palha. A área está inserida na província geomorfológica do Planalto Ocidental Paulista, apresentando três materiais de origem relacionados à transição entre Basaltos Serra Geral, Depósito Colúvio Eluvionar e Depósito Aluvionar, quatro tipos de Latossolos e um Neossolo, além de geomorfologia caracterizada por áreas côncavas e convexas. Foram coletadas 372 amostras na profundidade de 0,00-0,25 m para a avaliação dos atributos do solo. Para o estudo da FCO2 foi delimitada uma área de 90 ha. Para avaliar os métodos indiretos ERD e SM, os dados foram comparados com os resultados de análises químicas, granulométricas e mineralógicas. Todos os dados foram submetidos à análise estatística clássica e geoestatística para avaliar a dependência e variabilidade espacial. A variabilidade de alguns atributos do solo foi estratificada por compartimentos (geologia, pedologia e geomorfologia), com o intuito de entender a influência de cada compartimento na variabilidade dos atributos estudados. A estratificação dos atributos do solo por compartimento geológico, pedológico e geomorfológico é eficaz para o estudo da variação dos atributos estudados. A ERD é uma ferramenta eficaz na caracterização de óxidos de ferro e na identificação das diferentes classes de solos. A SM é útil tanto para melhor detalhamento e readequação das classes de solo, quanto ao conteúdo de ferro e aos intervalos de classe textural, auxiliando na identificação de zonas de manejo. Todos os atributos estudados têm dependência espacial. Os mapas interpolados com base na predição dos atributos por SM e ERD apresentam padrão de variabilidade semelhante aos mapas baseados nos dados observados. No entanto, para solos com altos teores de óxidos de ferro, como os Latossolos férricos, a SM mostrou-se mais indicada para predizer os atributos estudados. Dentre os atributos estudados, os óxidos de ferro e a SM foram os principais preditores da FCO2, provando a eficiência destes como pedoindicadores dos fatores e processos de formação do solo.
This study aims: i) to characterize the clay mineralogy and study the spatial variability of the granulometric, chemical and mineralogical attributes of the soil based on geological, pedological and geomorphological information; ii) to evaluate the potential of diffuse reflectance spectroscopy (DRS) and magnetic susceptibility (MS) in the estimation of hematite (Hm) and goethite (Gt) iron oxides, granulometric and chemical attributes in the landscape compartments; iii) to use DRS and MS in the study of the quantification and spatial variability of soil CO2 emission (FCO2); and iv) to investigate the efficiency of the use of MS and iron oxides in pedotransfer functions (PTFs) for estimate the FCO2. The study area, 870 ha, is located in the municipality of Guatapará-São Paulo, and is cultivated with sugar cane managed with straw. The area is located in the geomorphological province of Plateau Western Paulista, presenting three materials of origin related to the transition between Serra Geral Basalts, Eluvial-Colluvial Deposit and Alluvial Deposit, four types of Oxisols and one Entisols, besides geomorphology characterized by concave and convex areas. A total of 372 samples were collected at a depth of 0.00-0.25 m for soil attributes. For the FCO2 study, an area of 90 ha was delimited. In order to evaluate the indirect methods DRS and MS, the data were compared with the results of chemical, granulometric and mineralogical analyzes. All data were submitted to classical and geostatistical statistical analysis to evaluate spatial dependence and variability. The variability of some soil attributes was stratified by compartments (geology, pedology and geomorphology), in order to understand the influence of each compartment on the variability of the attributes studied. The stratification of soil attributes for geological, pedological and geomorphological compartment is effective to study the variation of the attributes. DRS is an effective tool in the characterization of iron oxides and in the identification of different soil classes. MS is useful both for better detailing and re-adjustment of soil classes, iron content and textural class intervals, helping to identify management zones. All attributes studied have spatial dependence. The interpolated maps based on attribute prediction by MS and DRS show pattern of variability similar to maps based on observed data. However, for soils with high levels of iron oxides, such as ferric Oxisols, the MS was more indicated to predict the attributes studied. Among the attributes studied, iron oxides and MS were the main predictors of FCO2, proving their efficiency as pedoenvironmental of soil formation factors and processes.
This study aims: i) to characterize the clay mineralogy and study the spatial variability of the granulometric, chemical and mineralogical attributes of the soil based on geological, pedological and geomorphological information; ii) to evaluate the potential of diffuse reflectance spectroscopy (DRS) and magnetic susceptibility (MS) in the estimation of hematite (Hm) and goethite (Gt) iron oxides, granulometric and chemical attributes in the landscape compartments; iii) to use DRS and MS in the study of the quantification and spatial variability of soil CO2 emission (FCO2); and iv) to investigate the efficiency of the use of MS and iron oxides in pedotransfer functions (PTFs) for estimate the FCO2. The study area, 870 ha, is located in the municipality of Guatapará-São Paulo, and is cultivated with sugar cane managed with straw. The area is located in the geomorphological province of Plateau Western Paulista, presenting three materials of origin related to the transition between Serra Geral Basalts, Eluvial-Colluvial Deposit and Alluvial Deposit, four types of Oxisols and one Entisols, besides geomorphology characterized by concave and convex areas. A total of 372 samples were collected at a depth of 0.00-0.25 m for soil attributes. For the FCO2 study, an area of 90 ha was delimited. In order to evaluate the indirect methods DRS and MS, the data were compared with the results of chemical, granulometric and mineralogical analyzes. All data were submitted to classical and geostatistical statistical analysis to evaluate spatial dependence and variability. The variability of some soil attributes was stratified by compartments (geology, pedology and geomorphology), in order to understand the influence of each compartment on the variability of the attributes studied. The stratification of soil attributes for geological, pedological and geomorphological compartment is effective to study the variation of the attributes. DRS is an effective tool in the characterization of iron oxides and in the identification of different soil classes. MS is useful both for better detailing and re-adjustment of soil classes, iron content and textural class intervals, helping to identify management zones. All attributes studied have spatial dependence. The interpolated maps based on attribute prediction by MS and DRS show pattern of variability similar to maps based on observed data. However, for soils with high levels of iron oxides, such as ferric Oxisols, the MS was more indicated to predict the attributes studied. Among the attributes studied, iron oxides and MS were the main predictors of FCO2, proving their efficiency as pedoenvironmental of soil formation factors and processes.
Descrição
Palavras-chave
Mineralogia da fração argila, Emissão de CO2 do solo, Relação solo-paisagem, Funções de pedotransferência, Geoestatística, Pedometria, Clay mineralogy, Soil CO2 emission, Soil-landscape, Pedotransfer functions, Geostatistics, Pedometrics