VIS-NIR spectral reflectance for discretization of soils with high sand content / Refletância espectral VIS-NIR para discretização de solos com alto teor de areia

The aim of this study is to evaluate the spatial distribution and relationships between the physicochemical attributes and radiometry of soils with high sand contents. One hundred surface horizon samples were collected for physicochemical and spectral analyses of the soil. The samples were selected spatially by the conditioned Latin hypercube method. The physicochemical analyses consisted of granulometry, organic carbon content, and iron oxides content, extracted using sodium dithionite-citrate-bicarbonate (DCB). The spectral response of the soils was analyzed in the 400 to 1000 nm range. The spectral curves were obtained from the samples of the surface horizons, which were categorized according to the attribute in question. The relationship between the soil physicochemical attributes and soil radiometry was evaluated through a Pearson's correlation. There was a tendency for the organic carbon content to decrease with an increase in soil depth, associated with the presence of soils with higher sand contents. For soils with iron contents lower than 80 g kg <->1, there was an increase in the reflectance along the spectrum, whereas for soils with contents between 80 and 160 g kg <->1, the reflectance decreased after 600 nm, with greater variation along the spectrum for soils with iron contents higher than 120 g kg <->1. The diffuse reflectance spectroscopy could potentially allow for granulometric distinction between the soils evaluated.(AU)

Este estudo objetivou avaliar a discretização espacial e relações entre atributos físico-químicos com a radiometria dos solos com altos teores de areia. Foram coletadas 100 (cem) amostras de horizontes superficiais para análises físico-químicas e espectrais do solo, selecionadas espacialmente pelo método do hipercúbico latino condicionado. As análises físico-químicas foram a granulometria, teores de carbono orgânico e de óxidos de ferro extraído por ditionito-citrato-bicarbonato de sódio (DCB). A resposta espectral dos solos foi analisada na faixa de 400 a 1000 nm. As curvas foram elaboradas a partir da média de reflectância espectral de cem amostras de horizontes superficiais categorizados de acordo com o atributo em questão. A relação entre os atributos físico-químicos do solo e a radiometria dos solos foi avaliada através da correlação de Pearson. Houve a tendência do decréscimo nos teores de carbono orgânico com a diminuição da altitude, associada a presença de solos com maiores teores de areia. Para os solos com teores de ferro inferiores 80 g kg <->1 houve um aumento da refletância ao longo do espectro, enquanto que solos com teores entre 80 a 160 g kg <->1 a refletância decresceu significativamente após os 600 nm, com maior variação nos solos com teores de ferro superiores a 120 g kg <->1. A espectroscopia de refletância difusa mostrou-se uma ferramenta com potencial de distinção granulométrica para os solos avaliados.(AU)

Clinical and radiographic evaluation of double pelvic osteotomy to treat canine hip dysplasia / Avaliação clínica e radiográfica da osteotomia dupla da pelve no tratamento da displasia coxofemoral canina

The purpose of this study was to describe our initial experience with double pelvic osteotomy (DPO) in young dogs affected by hip dysplasia (HD) and to report their postoperative outcome. Seven dogs (four females and three males) were included in our study with mean age 8.3 (±1.7) months, and mean body weight 29.5 (±7.4)Kg. Breeds involved were: Rottweiler (n = 1), Labrador Retriever (n = 3), Golden Retriever (n = 1), Great Dane (n=1) and São Miguel Cattle Dog (n = 1). The most common history complaints were: pelvic limb lameness and pain at hip extension and hip abduction. All surgical procedures consisted of osteotomy of the ilium and pubis, acetabular ventroversion and iliac stabilization with a customized bone plate with seven screws, four screws placed at the cranial fragment and the remaining three in the caudal aspect. Average surgical time was 65.8 (±10.4) minutes and median follow-up assessment was 68 (±15) days. Fracture healing was observed within mean period of 26.3 (±8.9) days. Six patients (86%) had satisfactory outcome and one patient didn’t improve after surgery and had to undergo a total hip replacement. Our results showed that DPO is an effective treatment for HD due to the preservation of pelvic geometry and low postoperative morbidity. Since it is a recent technique, further studies are recommended.

O objetivo do estudo é a descrição da osteotomia dupla da pelve (ODP) em pacientes com displasia coxofemoral (DCF) e relatar a evolução pós-operatória. As raças acometidas foram: Rottweiler (n=1), Labrador (n=3), Golden Retriver (n=1), Dogue alemão (n=1) e Fila de São Miguel (n=1). O total foi de sete animais, sendo três machos e quatro fêmeas; a média de idade e peso dos cães foi de 8,3±1,7 meses e 29,5±7,4Kg, respectivamente. As queixas iniciais mais comuns antes da cirurgia foram: claudicação em membro pélvico e dor à extensão e abdução do quadril. A cirurgia constou em realizar a osteotomia do ílio e púbis, rotacão axial do acetábulo sobre a cabeça do fêmur e osteossíntese do ílio com a utilização de placa fixada com sete parafusos, quatro destes no segmento cranial e três no segmento caudal. Após a cirurgia um animal não apresentou melhora do quadro, caracterizado por agravamento da subluxação coxofemoral, sendo submetido à prótese total de quadril. O tempo médio de cirurgia foi de 65,8±10,4 minutos e o período de acompanhamento médio pós operatório foi de 68,0±15,0dias, visibilizando a reação osteoproliferativa no foco de osteotomia ilíaca em um período médio de 26,3±8,9 dias. Dos sete animais envolvidos no estudo, seis tiveram recuperação satisfatória após o primeiro procedimento no período avaliado. Os resultados apontam a técnica de OPD como procedimento eficiente no tratamento de DCF devido à preservação da geometria pélvica e baixa morbidade pós-operatória. Por se tratar de uma recente técnica, ainda pouco difundida, é interessante a realização de maiores estudos.

Clinical and radiographic evaluation of double pelvic osteotomy to treat canine hip dysplasia / Avaliação clínica e radiográfica da osteotomia dupla da pelve no tratamento da displasia coxofemoral canina

The purpose of this study was to describe our initial experience with double pelvic osteotomy (DPO) in young dogs affected by hip dysplasia (HD) and to report their postoperative outcome. Seven dogs (four females and three males) were included in our study with mean age 8.3 (±1.7) months, and mean body weight 29.5 (±7.4)Kg. Breeds involved were: Rottweiler (n = 1), Labrador Retriever (n = 3), Golden Retriever (n = 1), Great Dane (n=1) and São Miguel Cattle Dog (n = 1). The most common history complaints were: pelvic limb lameness and pain at hip extension and hip abduction. All surgical procedures consisted of osteotomy of the ilium and pubis, acetabular ventroversion and iliac stabilization with a customized bone plate with seven screws, four screws placed at the cranial fragment and the remaining three in the caudal aspect. Average surgical time was 65.8 (±10.4) minutes and median follow-up assessment was 68 (±15) days. Fracture healing was observed within mean period of 26.3 (±8.9) days. Six patients (86%) had satisfactory outcome and one patient didnt improve after surgery and had to undergo a total hip replacement. Our results showed that DPO is an effective treatment for HD due to the preservation of pelvic geometry and low postoperative morbidity. Since it is a recent technique, further studies are recommended.(AU)

O objetivo do estudo é a descrição da osteotomia dupla da pelve (ODP) em pacientes com displasia coxofemoral (DCF) e relatar a evolução pós-operatória. As raças acometidas foram: Rottweiler (n=1), Labrador (n=3), Golden Retriver (n=1), Dogue alemão (n=1) e Fila de São Miguel (n=1). O total foi de sete animais, sendo três machos e quatro fêmeas; a média de idade e peso dos cães foi de 8,3±1,7 meses e 29,5±7,4Kg, respectivamente. As queixas iniciais mais comuns antes da cirurgia foram: claudicação em membro pélvico e dor à extensão e abdução do quadril. A cirurgia constou em realizar a osteotomia do ílio e púbis, rotacão axial do acetábulo sobre a cabeça do fêmur e osteossíntese do ílio com a utilização de placa fixada com sete parafusos, quatro destes no segmento cranial e três no segmento caudal. Após a cirurgia um animal não apresentou melhora do quadro, caracterizado por agravamento da subluxação coxofemoral, sendo submetido à prótese total de quadril. O tempo médio de cirurgia foi de 65,8±10,4 minutos e o período de acompanhamento médio pós operatório foi de 68,0±15,0dias, visibilizando a reação osteoproliferativa no foco de osteotomia ilíaca em um período médio de 26,3±8,9 dias. Dos sete animais envolvidos no estudo, seis tiveram recuperação satisfatória após o primeiro procedimento no período avaliado. Os resultados apontam a técnica de OPD como procedimento eficiente no tratamento de DCF devido à preservação da geometria pélvica e baixa morbidade pós-operatória. Por se tratar de uma recente técnica, ainda pouco difundida, é interessante a realização de maiores estudos.(AU)

Temporal dynamics of spectral reflectance and vegetation indices during canola crop cycle in southern Brazil / Dinâmica temporal dos índices da reflectância espectral e índices de vegetação durante o ciclo da cultura de canola no Sul do Brasil

The objective of this study was to characterize the variability of spectral reflectance and temporal profiles of vegetation indices associated with nitrogen fertilization, crop cycle periods, and weather conditions of the growing season in canola canopies in southern Brazil. An experiment was carried out during the 2013 and 2014 canola growing seasons at EMBRAPA Trigo, Passo Fundo, state of Rio Grande do Sul, Brazil. The experiment was conducted in a randomized block design with four replications. Five doses of nitrogen top dressing were used as treatments: 10, 20, 40, 80, and 160kg ha-1. Measurements were obtained with the spectroradiometer positioned above the canopy, to construct spectral reflectance curves for canola and establish temporal profiles for several vegetation indices (SR, NDVI, EVI, SAVI, and GNDVI). In addition, data on shoot dry matter were obtained and phenological stages were determined. The spectral reflectance curves of canola were reported to change with canopy growth and development. Temporal profiles of vegetation indices showed two maximum peaks, one before flowering and other after flowering. The indices SR, NDVI, EVI, SAVI, and GNDVI were able to characterize changes in the canola canopy over time, as a function of phenological phases, weather conditions, and nitrogen fertilization, throughout the development cycle. Plant growth and development, variations in crop management, and environmental conditions affect the spectral response of canola.

O objetivo deste trabalho foi caracterizar a variabilidade da reflectância espectral e dos perfis temporais dos índices de vegetação de dosséis de canola, associada à adubação nitrogenada, aos períodos do ciclo da cultura e às condições meteorológicas no sul do Brasil. Foi instalado um experimento nas safras de 2013 e 2014, na EMBRAPA Trigo, em Passo Fundo, RS. O delineamento experimental foi de blocos casualizados com quatro repetições. Foram utilizados os tratamentos de cinco doses de nitrogênio em cobertura: 10, 20, 40, 80, 160kg ha-1. Foram realizadas medições com espectrorradiômetro, sobre o dossel, para compor curvas de reflectância espectral da canola e perfis temporais dos índices de vegetação SR, NDVI, EVI, SAVI e GNDVI. Também foram obtidos dados de matéria seca da parte aérea e feitas determinações de fenologia. Verificou-se que as curvas de reflectância espectral da canola mudaram com o crescimento e desenvolvimento do dossel. Os perfis temporais dos índices de vegetação apresentaram dois picos máximos, um antes e outro após o florescimento. Os índices SR, NDVI, EVI, SAVI e GNDVI foram capazes de caracterizar temporalmente as modificações do dossel da canola ao longo do ciclo, em função de fases fenológicas, condições meteorológicas e adubação nitrogenada. O crescimento e desenvolvimento das plantas, as variações de manejo da cultura e as condições ambientais afetam a resposta espectral da canola.

Temporal dynamics of spectral reflectance and vegetation indices during canola crop cycle in southern Brazil / Dinâmica temporal dos índices da reflectância espectral e índices de vegetação durante o ciclo da cultura de canola no Sul do Brasil

The objective of this study was to characterize the variability of spectral reflectance and temporal profiles of vegetation indices associated with nitrogen fertilization, crop cycle periods, and weather conditions of the growing season in canola canopies in southern Brazil. An experiment was carried out during the 2013 and 2014 canola growing seasons at EMBRAPA Trigo, Passo Fundo, state of Rio Grande do Sul, Brazil. The experiment was conducted in a randomized block design with four replications. Five doses of nitrogen top dressing were used as treatments: 10, 20, 40, 80, and 160kg ha-1. Measurements were obtained with the spectroradiometer positioned above the canopy, to construct spectral reflectance curves for canola and establish temporal profiles for several vegetation indices (SR, NDVI, EVI, SAVI, and GNDVI). In addition, data on shoot dry matter were obtained and phenological stages were determined. The spectral reflectance curves of canola were reported to change with canopy growth and development. Temporal profiles of vegetation indices showed two maximum peaks, one before flowering and other after flowering. The indices SR, NDVI, EVI, SAVI, and GNDVI were able to characterize changes in the canola canopy over time, as a function of phenological phases, weather conditions, and nitrogen fertilization, throughout the development cycle. Plant growth and development, variations in crop management, and environmental conditions affect the spectral response of canola.(AU)

O objetivo deste trabalho foi caracterizar a variabilidade da reflectância espectral e dos perfis temporais dos índices de vegetação de dosséis de canola, associada à adubação nitrogenada, aos períodos do ciclo da cultura e às condições meteorológicas no sul do Brasil. Foi instalado um experimento nas safras de 2013 e 2014, na EMBRAPA Trigo, em Passo Fundo, RS. O delineamento experimental foi de blocos casualizados com quatro repetições. Foram utilizados os tratamentos de cinco doses de nitrogênio em cobertura: 10, 20, 40, 80, 160kg ha-1. Foram realizadas medições com espectrorradiômetro, sobre o dossel, para compor curvas de reflectância espectral da canola e perfis temporais dos índices de vegetação SR, NDVI, EVI, SAVI e GNDVI. Também foram obtidos dados de matéria seca da parte aérea e feitas determinações de fenologia. Verificou-se que as curvas de reflectância espectral da canola mudaram com o crescimento e desenvolvimento do dossel. Os perfis temporais dos índices de vegetação apresentaram dois picos máximos, um antes e outro após o florescimento. Os índices SR, NDVI, EVI, SAVI e GNDVI foram capazes de caracterizar temporalmente as modificações do dossel da canola ao longo do ciclo, em função de fases fenológicas, condições meteorológicas e adubação nitrogenada. O crescimento e desenvolvimento das plantas, as variações de manejo da cultura e as condições ambientais afetam a resposta espectral da canola.(AU)

Spectral indices for the detection of salinity effects in melon plants

Water scarcity and soil salinization affect large semiarid agricultural areas throughout the world. The maintenance of agricultural productivity implies better agricultural practices and a careful selection of resistant crops. A proper monitoring of the physiological status of plants can lead to better knowledge of plant nutritional requirements. Visible and near-infrared (VNIR) radiometry provides a non-destructive and quantitative method to monitor vegetation status by quantifying chemical properties using spectroscopic techniques. In this study, the capability of VNIR spectral measurements to detect salinity effects on melon (Cucumis melo L.) plants was tested. Melon plants were cultivated under multiple soil salinity conditions (electrical conductivity, (EC)1:5: 0.5, 1.0 and 2.5 dS m-1). Spectral data of leaves were transformed into vegetation indices indicative of the physiological status of the plants. The results showed differences for N (p 0.05), K and Na content (p 0.01) due to salinity suggesting different degrees of salt stress on the plants. Specific leaf area increased with salinity levels (p 0.001). The capabilities of VNIR radiometry to assess the influence of soil salinity on melon physiology using a non-destructive method were demonstrated. A normalized difference vegetation index (NDVI750-705), and the ratio between water index (WI) and normalized difference vegetation index (WI/NDVI750-705) showed significant relationships (p 0.01) with the salinity. Therefore, this method could be used for in-situ early detection of salinity stress effects.

Spectral indices for the detection of salinity effects in melon plants

Water scarcity and soil salinization affect large semiarid agricultural areas throughout the world. The maintenance of agricultural productivity implies better agricultural practices and a careful selection of resistant crops. A proper monitoring of the physiological status of plants can lead to better knowledge of plant nutritional requirements. Visible and near-infrared (VNIR) radiometry provides a non-destructive and quantitative method to monitor vegetation status by quantifying chemical properties using spectroscopic techniques. In this study, the capability of VNIR spectral measurements to detect salinity effects on melon (Cucumis melo L.) plants was tested. Melon plants were cultivated under multiple soil salinity conditions (electrical conductivity, (EC)1:5: 0.5, 1.0 and 2.5 dS m-1). Spectral data of leaves were transformed into vegetation indices indicative of the physiological status of the plants. The results showed differences for N (p 0.05), K and Na content (p 0.01) due to salinity suggesting different degrees of salt stress on the plants. Specific leaf area increased with salinity levels (p 0.001). The capabilities of VNIR radiometry to assess the influence of soil salinity on melon physiology using a non-destructive method were demonstrated. A normalized difference vegetation index (NDVI750-705), and the ratio between water index (WI) and normalized difference vegetation index (WI/NDVI750-705) showed significant relationships (p 0.01) with the salinity. Therefore, this method could be used for in-situ early detection of salinity stress effects.(AU)

Preventing injuries caused by radiotelemetry collars in reintroduced red-rumped agoutis, Dasyprocta leporina (Rodentia: Dasyproctidae), in Atlantic Forest, southeastern Brazil

Reintroduction has been recognized as a powerful conservation tool, but in order to ensure its success, animal monitoring is highly recommended. One way to monitor released animals is to put radiotelemetry collars on them. These devices, however, can harm the subjects, causing serious wounds. Our objectives in this work were to describe the injuries caused by a radiotelemetry collar model on reintroduced agoutis and to propose modifications to it. We equipped agoutis with TXE-311C radio collars (Telenax Wildlife Telemetry) before releasing them in the wild. They acquired serious wounds and one animal died. We then modified the collar structure to reduce its width and retention of water. After these modifications, the injuries did not occur again. As reintroduction is an expensive conservation strategy, any improvement that maximize its probability of success is important. We believe that the improvements we propose here have the potential to enhance the success of reintroductions and to increase animal welfare. This recommendation is more important when captive animals are re-introduced, because they tend to have lower immunity, particularly when they are released in rainy habitats.

Preventing injuries caused by radiotelemetry collars in reintroduced red-rumped agoutis, Dasyprocta leporina (Rodentia: Dasyproctidae), in Atlantic Forest, southeastern Brazil

Reintroduction has been recognized as a powerful conservation tool, but in order to ensure its success, animal monitoring is highly recommended. One way to monitor released animals is to put radiotelemetry collars on them. These devices, however, can harm the subjects, causing serious wounds. Our objectives in this work were to describe the injuries caused by a radiotelemetry collar model on reintroduced agoutis and to propose modifications to it. We equipped agoutis with TXE-311C radio collars (Telenax Wildlife Telemetry) before releasing them in the wild. They acquired serious wounds and one animal died. We then modified the collar structure to reduce its width and retention of water. After these modifications, the injuries did not occur again. As reintroduction is an expensive conservation strategy, any improvement that maximize its probability of success is important. We believe that the improvements we propose here have the potential to enhance the success of reintroductions and to increase animal welfare. This recommendation is more important when captive animals are re-introduced, because they tend to have lower immunity, particularly when they are released in rainy habitats.(AU)

Avaliação das doses resultantes de procedimentos radiodiagnósticos realizados em medicina veterinária e avaliação das doses secundárias de radiação espalhada no corpo clínico e nos proprietários dos animais / Evaluation of doses from radiodiagnotic procedures performed in veterinary medicine and assessing of the doses of secondary radiation in the medical staff and animal owners

O objetivo primordial em radiologia veterinária é a produção de radiografias com qualidade diagnóstica, em uma primeira tentativa. Esse objetivo deve atender a três propósitos: (1) diminuir a exposição à radiação do paciente e trabalhadores; (2) diminuir o custo do estudo para o cliente e (3) produzir dados diagnósticos para rápida interpretação e tratamento do paciente. Esse trabalho teve por objetivo a determinação das doses em cães submetidos a radiografias de tórax e abdômen utilizando a técnica da dosimetria termoluminescente (TL). As doses de radiação foram avaliadas com a utilização de dosímetros termoluminescentes de sulfato de cálcio dopado com disprósio (CaSO4:Dy) e fluoreto de lítio dopado com magnésio e titânio (LiF:Mg,Ti). Os resultados obtidos indicam que é extremamente importante a avaliação das doses de radiação envolvidas em procedimentos diagnósticos de radiologia veterinária, para a avaliação das doses nos animais e para ser usado como um parâmetro para a monitoração individual dos proprietários de animais, que auxiliam no posicionamento, e para a proteção dos trabalhadores ocupacionalmente expostos nas Clínicas de Radiologia Veterinária.

The primary goal in veterinary radiography is to produce radiographs of diagnostic quality on the first attempt. This goal serves three purposes: (1) to decrease radiation exposure to the patient and veterinary personnel; (2) to decrease the cost of the study for the client; and (3) to produce diagnostic data for rapid interpretation and treatment of the patient. This work aimed to determine the doses in dogs submitted to chest and abdomen Xrays using the technique of thermoluminescence (TL) dosimetry. The radiation doses were assessed using thermoluminescent dosimeters of calcium sulphate doped with dysprosium (CaSO4:Dy) and lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti). The obtained results indicate that is extremely important the assessment of radiation doses involved in veterinary diagnostic radiology procedures, to evaluate the delivered doses to the animals, to be used as a parameter in the individual monitoring of pets owners, who assist the animal positioning, and to protect occupationally exposed workers at the Veterinary Radiology Clinics.

Avaliação das doses resultantes de procedimentos radiodiagnósticos realizados em medicina veterinária e avaliação das doses secundárias de radiação espalhada no corpo clínico e nos proprietários dos animais / Evaluation of doses from radiodiagnotic procedures performed in veterinary medicine and assessing of the doses of secondary radiation in the medical staff and animal owners

O objetivo primordial em radiologia veterinária é a produção de radiografias com qualidade diagnóstica, em uma primeira tentativa. Esse objetivo deve atender a três propósitos: (1) diminuir a exposição à radiação do paciente e trabalhadores; (2) diminuir o custo do estudo para o cliente e (3) produzir dados diagnósticos para rápida interpretação e tratamento do paciente. Esse trabalho teve por objetivo a determinação das doses em cães submetidos a radiografias de tórax e abdômen utilizando a técnica da dosimetria termoluminescente (TL). As doses de radiação foram avaliadas com a utilização de dosímetros termoluminescentes de sulfato de cálcio dopado com disprósio (CaSO4:Dy) e fluoreto de lítio dopado com magnésio e titânio (LiF:Mg,Ti). Os resultados obtidos indicam que é extremamente importante a avaliação das doses de radiação envolvidas em procedimentos diagnósticos de radiologia veterinária, para a avaliação das doses nos animais e para ser usado como um parâmetro para a monitoração individual dos proprietários de animais, que auxiliam no posicionamento, e para a proteção dos trabalhadores ocupacionalmente expostos nas Clínicas de Radiologia Veterinária. (AU)

The primary goal in veterinary radiography is to produce radiographs of diagnostic quality on the first attempt. This goal serves three purposes: (1) to decrease radiation exposure to the patient and veterinary personnel; (2) to decrease the cost of the study for the client; and (3) to produce diagnostic data for rapid interpretation and treatment of the patient. This work aimed to determine the doses in dogs submitted to chest and abdomen Xrays using the technique of thermoluminescence (TL) dosimetry. The radiation doses were assessed using thermoluminescent dosimeters of calcium sulphate doped with dysprosium (CaSO4:Dy) and lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti). The obtained results indicate that is extremely important the assessment of radiation doses involved in veterinary diagnostic radiology procedures, to evaluate the delivered doses to the animals, to be used as a parameter in the individual monitoring of pets owners, who assist the animal positioning, and to protect occupationally exposed workers at the Veterinary Radiology Clinics. (AU)

VIS-NIR spectral reflectance for discretization of soils with high sand content / Refletância espectral VIS-NIR para discretização de solos com alto teor de areia

The aim of this study is to evaluate the spatial distribution and relationships between the physicochemical attributes and radiometry of soils with high sand contents. One hundred surface horizon samples were collected for physicochemical and spectral analyses of the soil. The samples were selected spatially by the conditioned Latin hypercube method. The physicochemical analyses consisted of granulometry, organic carbon content, and iron oxides content, extracted using sodium dithionite-citrate-bicarbonate (DCB). The spectral response of the soils was analyzed in the 400 to 1000 nm range. The spectral curves were obtained from the samples of the surface horizons, which were categorized according to the attribute in question. The relationship between the soil physicochemical attributes and soil radiometry was evaluated through a Pearson's correlation. There was a tendency for the organic carbon content to decrease with an increase in soil depth, associated with the presence of soils with higher sand contents. For soils with iron contents lower than 80 g kg

Este estudo objetivou avaliar a discretização espacial e relações entre atributos físico-químicos com a radiometria dos solos com altos teores de areia. Foram coletadas 100 (cem) amostras de horizontes superficiais para análises físico-químicas e espectrais do solo, selecionadas espacialmente pelo método do hipercúbico latino condicionado. As análises físico-químicas foram a granulometria, teores de carbono orgânico e de óxidos de ferro extraído por ditionito-citrato-bicarbonato de sódio (DCB). A resposta espectral dos solos foi analisada na faixa de 400 a 1000 nm. As curvas foram elaboradas a partir da média de reflectância espectral de cem amostras de horizontes superficiais categorizados de acordo com o atributo em questão. A relação entre os atributos físico-químicos do solo e a radiometria dos solos foi avaliada através da correlação de Pearson. Houve a tendência do decréscimo nos teores de carbono orgânico com a diminuição da altitude, associada a presença de solos com maiores teores de areia. Para os solos com teores de ferro inferiores 80 g kg