Evaluation of the degradation of two bioabsorbable interference screws: an in-vivo study in sheep

Purpose: To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + ß-tri-calcium phosphate (ß-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery. Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/ß-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions: The inclusion of ß-TCP favors screw degradation since the PDLLA/ß-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/ß-TCP screws presented less bone tissue at the implantation site.

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.(AU)

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

Abstract Background: The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.

Experimental study of amniotic membrane or topical propolis on induced cutaneous wound healing in Wistar rats / Estudo experimental do uso da membrana amniótica e da própolis tópica na cicatrização de feridas cutâneas induzidas em ratos Wistar

The study of propolis and the amniotic membrane as alternatives to promote the acceleration of healing has grown considerably. These products have shown to be easy to use, have bactericidal or bacteriostatic action and are affordable. The objective of the present study was to evaluate the action of the amniotic membrane of bitches and propolis in the healing of surgical wounds. To evaluate the efficacy of these methods the time for conclusion of the healing process of both groups was compared with a control group. In addition, the inflammatory response of each group was also evaluated to identify which alternative method could induce a better response in the healing process compared to the control group. For this purpose, 27 animals, Rattus norvegicus, variety Wistar, were used. Rats were separated into 3 groups with 9 animals each. Group I represented the 25% alcoholic propolis solution; Group II, Amniotic membrane; Group III was Control group. Wounds were assessed macroscopically for the lesion area, and microscopically for the histological quality of each wound layer and the intensity of inflammation and collagen deposition. After the macroscopic analysis, it was observed that there were no statistical differences among the 3 groups (p> 0.05) relevant to accelerate the healing process in terms of presence of inflammatory cells, fibroblasts, collagen, neovascularization, granulation tissue and re-epithelialization.

O estudo da própolis e da membrana amniótica como alternativa para promover a aceleração da cicatrização vem crescendo bastante, numa tentativa de buscar métodos alternativos para cicatrização de feridas que apresentem fácil utilização, ação bactericida ou bacteriostática e tenha custo acessível. Com o presente estudo objetivou-se avaliar a ação da membrana amniótica de cadelas e da própolis na cicatrização de feridas cirúrgicas, comparando o tempo no processo de cicatrização com o grupo controle e a resposta inflamatória de cada um, de maneira a identificar qual método alternativo induzirá melhor res-posta no processo de cicatrização em comparação ao grupo controle. Para tanto, foram utilizados 27 animais, Rattus norve-gicus, variedade Wistar, separados em três grupos com nove animais cada, sendo Grupo I – solução alcoólica de própolis a 25%; Grupo II – Membrana amniótica de cadelas; Grupo III – Grupo controle. As feridas foram avaliadas macroscopica-mente quanto à área da lesão, e microscopicamente quanto à qualidade histológica de cada leito da ferida e à intensidade de inflamação e deposição de colágeno. Após a análise macroscópica, constatou-se que não houve diferenças estatísticas (p>0,05) relevantes para acelerar o processo cicatricial, quanto a presença de células inflamatórias, fibroblastos, colágeno, neovasculari-zação, tecido de granulação e reepitelização, perante os tratamentos alternativos e o grupo controle no processo de cicatrização.

Experimental study of amniotic membrane or topical propolis on induced cutaneous wound healing in Wistar rats / Estudo experimental do uso da membrana amniótica e da própolis tópica na cicatrização de feridas cutâneas induzidas em ratos Wistar

The study of propolis and the amniotic membrane as alternatives to promote the acceleration of healing has grown considerably. These products have shown to be easy to use, have bactericidal or bacteriostatic action and are affordable. The objective of the present study was to evaluate the action of the amniotic membrane of bitches and propolis in the healing of surgical wounds. To evaluate the efficacy of these methods the time for conclusion of the healing process of both groups was compared with a control group. In addition, the inflammatory response of each group was also evaluated to identify which alternative method could induce a better response in the healing process compared to the control group. For this purpose, 27 animals, Rattus norvegicus, variety Wistar, were used. Rats were separated into 3 groups with 9 animals each. Group I represented the 25% alcoholic propolis solution; Group II, Amniotic membrane; Group III was Control group. Wounds were assessed macroscopically for the lesion area, and microscopically for the histological quality of each wound layer and the intensity of inflammation and collagen deposition. After the macroscopic analysis, it was observed that there were no statistical differences among the 3 groups (p> 0.05) relevant to accelerate the healing process in terms of presence of inflammatory cells, fibroblasts, collagen, neovascularization, granulation tissue and re-epithelialization.(AU)

O estudo da própolis e da membrana amniótica como alternativa para promover a aceleração da cicatrização vem crescendo bastante, numa tentativa de buscar métodos alternativos para cicatrização de feridas que apresentem fácil utilização, ação bactericida ou bacteriostática e tenha custo acessível. Com o presente estudo objetivou-se avaliar a ação da membrana amniótica de cadelas e da própolis na cicatrização de feridas cirúrgicas, comparando o tempo no processo de cicatrização com o grupo controle e a resposta inflamatória de cada um, de maneira a identificar qual método alternativo induzirá melhor res-posta no processo de cicatrização em comparação ao grupo controle. Para tanto, foram utilizados 27 animais, Rattus norve-gicus, variedade Wistar, separados em três grupos com nove animais cada, sendo Grupo I solução alcoólica de própolis a 25%; Grupo II Membrana amniótica de cadelas; Grupo III Grupo controle. As feridas foram avaliadas macroscopica-mente quanto à área da lesão, e microscopicamente quanto à qualidade histológica de cada leito da ferida e à intensidade de inflamação e deposição de colágeno. Após a análise macroscópica, constatou-se que não houve diferenças estatísticas (p>0,05) relevantes para acelerar o processo cicatricial, quanto a presença de células inflamatórias, fibroblastos, colágeno, neovasculari-zação, tecido de granulação e reepitelização, perante os tratamentos alternativos e o grupo controle no processo de cicatrização.(AU)

Determination of the value of vertebral heart size regarding the weight and body area in canines / Determinação dos valores do vertebral heart size em relação ao peso e área corporal canina

The vertebral heart size is a method used to measure the cardiac dimension in order to identify the remodeling of the chambres in heart disease. This study aims to determinate the vertebral heart size values at right lateral and ventrodorsal radiographs views relating to canines weight and body area variations. For the purpose of the study 40 healthy dogs within the age of 1 to 6 years, males and females, with deep or intermediated thorax were selected, brachycephalic dogs were not included in the study; the dogs were separated in four groups: group 1(n=9) compound of dogs up to 5 kg; group 2 (n=8) with dogs from 5,1 to 10 kg; group 3 (n=12) with dogs from 10,1 to19 kg and group 4 (n=11) with dogs weighing more than 19,1 kg. The values of body score, body mass index and the thorax configuration where previously measured, as well as the vertebral heart size and the depth width ratio from the radiographs. The results demonstrated intervals of right lateral-lateral vertebral heart size 9.9 to 10.4v and ventro-dorsal vertebral heart size of 9.8-10.3v. The study results show that the vertebral heart size numbers did not correlate with weight or body area, regardless the type of radiography view. Therefore, it can be concluded that the vertebral heart size in right lateral and ventrodorsal radiography can be used to rate the cardiac area, not suffering influence by the dog's weight or body area.

O vertebral heart size é um método utilizado para mensurar a dimensão cardíaca visando identificar os remodelamentos das câmaras nas cardiopatias. O objetivo do estudo foi determinar os valores de vertebral heart size nas projeções radiográficas latero-lateral direita e ventro-dorsal conforme as variações do peso e área corporal. Para isso, foram selecionados 40 cães hígidos com idade entre 1 e 6 anos, machos e fêmeas, com padrão torácico intermediário e profundo, com exclusão dos braquicefálicos; os cães foram divididos em quatro grupos: grupo 1 (n=9) composto por cães de até 5 kg; grupo 2 (n=8) com cães de 5,1 a 10 kg; grupo 3 (n=12) com cães de 10,1 a 19 kg e grupo 4 (n=11) com cães acima de 19,1 kg. Os valores de escore corporal, índice de massa corporal e conformação torácica foram previamente mensurados, bem como os valores dos vertebral heart size a relação profundidade/largura torácica das radiografias. Os resultados demonstraram intervalos de vertebral heart size latero-lateral 9.9 a 10.4v e vertebral heart size ventro dorsal de 9.8-10.3v. Os valores não apresentaram correlação com o peso e área corporal nos grupos estudados, independente das projeções estudas. Assim, pode-se concluir que método vertebral heart size nas projeções estudadas é aplicável na avaliação da área cardíaca, não sofrendo influências do peso e área corporal canina.

Determination of the value of vertebral heart size regarding the weight and body area in canines / Determinação dos valores do vertebral heart size em relação ao peso e área corporal canina

The vertebral heart size is a method used to measure the cardiac dimension in order to identify the remodeling of the chambres in heart disease. This study aims to determinate the vertebral heart size values at right lateral and ventrodorsal radiographs views relating to canines weight and body area variations. For the purpose of the study 40 healthy dogs within the age of 1 to 6 years, males and females, with deep or intermediated thorax were selected, brachycephalic dogs were not included in the study; the dogs were separated in four groups: group 1(n=9) compound of dogs up to 5 kg; group 2 (n=8) with dogs from 5,1 to 10 kg; group 3 (n=12) with dogs from 10,1 to19 kg and group 4 (n=11) with dogs weighing more than 19,1 kg. The values of body score, body mass index and the thorax configuration where previously measured, as well as the VHS and the depth width ratio from the radiographs. The results demonstrated intervals of right lateral-lateral vertebral heart size 9.9 to 10.4v and ventro-dorsal vertebral heart size of 9.8-10.3v. The study results show that the vertebral heart size numbers did not correlate with weight or body area, regardless the type of radiography view. Therefore, it can be concluded that the vertebral heart size in right lateral and ventrodorsal radiography can be used to rate the cardiac area, not suffering influence by the dog's weight or body area.(AU)

O vertebral heart size é um método utilizado para mensurar a dimensão cardíaca visando identificar os remodelamentos das câmaras nas cardiopatias. O objetivo do estudo foi determinar os valores de vertebral heart size nas projeções radiográficas latero-lateral direita e ventro-dorsal conforme as variações do peso e área corporal. Para isso, foram selecionados 40 cães hígidos com idade entre 1 e 6 anos, machos e fêmeas, com padrão torácico intermediário e profundo, com exclusão dos braquicefálicos; os cães foram divididos em quatro grupos: grupo 1 (n=9) composto por cães de até 5 kg; grupo 2 (n=8) com cães de 5,1 a 10 kg; grupo 3 (n=12) com cães de 10,1 a 19 kg e grupo 4 (n=11) com cães acima de 19,1 kg. Os valores de escore corporal, índice de massa corporal e conformação torácica foram previamente mensurados, bem como os valores dos vertebral heart size a relação profundidade/largura torácica das radiografias. Os resultados demonstraram intervalos de vertebral heart size latero-lateral 9.9 a 10.4v e vertebral heart size ventro dorsal de 9.8-10.3v. Os valores não apresentaram correlação com o peso e área corporal nos grupos estudados, independente das projeções estudas. Assim, pode-se concluir que método vertebral heart size nas projeções estudadas é aplicável na avaliação da área cardíaca, não sofrendo influências do peso e área corporal canina.(AU)

Determination of the value of vertebral heart size regarding the weight and body area in canines / Determinação dos valores do vertebral heart size em relação ao peso e área corporal canina

The vertebral heart size is a method used to measure the cardiac dimension in order to identify the remodeling of the chambres in heart disease. This study aims to determinate the vertebral heart size values at right lateral and ventrodorsal radiographs views relating to canines weight and body area variations. For the purpose of the study 40 healthy dogs within the age of 1 to 6 years, males and females, with deep or intermediated thorax were selected, brachycephalic dogs were not included in the study; the dogs were separated in four groups: group 1(n=9) compound of dogs up to 5 kg; group 2 (n=8) with dogs from 5,1 to 10 kg; group 3 (n=12) with dogs from 10,1 to19 kg and group 4 (n=11) with dogs weighing more than 19,1 kg. The values of body score, body mass index and the thorax configuration where previously measured, as well as the VHS and the depth width ratio from the radiographs. The results demonstrated intervals of right lateral-lateral vertebral heart size 9.9 to 10.4v and ventro-dorsal vertebral heart size of 9.8-10.3v. The study results show that the vertebral heart size numbers did not correlate with weight or body area, regardless the type of radiography view. Therefore, it can be concluded that the vertebral heart size in right lateral and ventrodorsal radiography can be used to rate the cardiac area, not suffering influence by the dog's weight or body area.

O vertebral heart size é um método utilizado para mensurar a dimensão cardíaca visando identificar os remodelamentos das câmaras nas cardiopatias. O objetivo do estudo foi determinar os valores de vertebral heart size nas projeções radiográficas latero-lateral direita e ventro-dorsal conforme as variações do peso e área corporal. Para isso, foram selecionados 40 cães hígidos com idade entre 1 e 6 anos, machos e fêmeas, com padrão torácico intermediário e profundo, com exclusão dos braquicefálicos; os cães foram divididos em quatro grupos: grupo 1 (n=9) composto por cães de até 5 kg; grupo 2 (n=8) com cães de 5,1 a 10 kg; grupo 3 (n=12) com cães de 10,1 a 19 kg e grupo 4 (n=11) com cães acima de 19,1 kg. Os valores de escore corporal, índice de massa corporal e conformação torácica foram previamente mensurados, bem como os valores dos vertebral heart size a relação profundidade/largura torácica das radiografias. Os resultados demonstraram intervalos de vertebral heart size latero-lateral 9.9 a 10.4v e vertebral heart size ventro dorsal de 9.8-10.3v. Os valores não apresentaram correlação com o peso e área corporal nos grupos estudados, independente das projeções estudas. Assim, pode-se concluir que método vertebral heart size nas projeções estudadas é aplicável na avaliação da área cardíaca, não sofrendo influências do peso e área corporal canina.

Color parameters applied to pedotransfer functions in the estimation of soil attributes / Parâmetros da cor aplicados a funções de pedotransferência na estimativa de atributos do solo

Global demands for an increased food production have prompted scientists to create technological innovations in various segments of the agricultural and environmental sectors. The use of diffuse reflectance spectroscopy in soil color determination to estimate its attributes is an example of these advances. Thus, the aim of this research was to identify the potential of the three parameters of the Munsell color system (Hue, Value, and Chroma) in estimating different chemical and particle size attributes by pedotransfer functions in a Typic Hapludox in the Cerrado of Piauí State, Brazil. This soil showed a yellowish color due to the goethite and low contents of bases and organic carbon. Among the calibrated pedotransfer functions, we observed that phosphorus, aluminum, hydrogen, potential acidity, potential cation exchange capacity, and base saturation could be estimated by Hue, while clay content by Value, and Chroma used to estimate hydrogen, potential acidity, and cation exchange capacity. We conclude that the parameter color could be used to estimate soil attributes.(AU)

As demandas mundiais por aumento na produção de alimentos vêm instigando os cientistas a criarem inovações tecnológicas em vários segmentos dos setores agrícolas e ambientais. O uso da espectroscopia de reflectância difusa na determinação da cor do solo para a estimativa de seus atributos é um exemplo destes avanços. Assim, objetivou-se com esta pesquisa identificar o potencial dos três parâmetros do sistema Munsell de cores (Matiz, Valor e Croma) em estimar diferentes atributos químicos e granulométricos por funções de pedotransferência, em LATOSSOLO AMARELO Distrófico típico no Cerrado do Estado do Piauí, Brasil. O solo apresentou coloração amarelada, como reflexo da goethita e também baixos teores de bases e carbono orgânico. Dentre as funções de pedotransferência calibradas, observamos que fósforo, alumínio, hidrogênio, acidez potencial, capacidade de troca catiônica potencial e saturação por bases podem ser estimada pela matiz, enquanto o teor de argila pode ser estimada pelo valor e o croma pode ser usado para estimar também hidrogênio, acidez potencial e capacidade de troca catiônica. Concluímos que é possível usar a cor para estimar atributos do solo.(AU)

Characterization of potential CO2 emissions in agricultural areas using magnetic susceptibility

ABSTRACT Soil CO2 emissions (fCO2) in agricultural areas have been widely studied in global climate change research, but its characterization and quantification are restricted to small areas. Because spatial and time variability affect emissions, tools need to be developed to predict fCO2 for large areas. This study aimed to investigate soil magnetic susceptibility (MS) and its correlation with fCO2 in an agricultural environment. The experiment was carried out on a Typic Eutrudox located in Guariba-SP, Brazil. Results showed that there was negative spatial correlation between fCO2 and the magnetic susceptibility of Air Dried Soil (MSADS) up to 34.3 m distant. However, the fCO2 had no significant correlation with MSADS, magnetic susceptibility of sand (MSSAND) nor clay (MSCLAY). However, MSADS could be a supplemental mean of identifying regions of high fCO2 potential over large areas.

Characterization of potential CO2 emissions in agricultural areas using magnetic susceptibility

ABSTRACT Soil CO2 emissions (fCO2) in agricultural areas have been widely studied in global climate change research, but its characterization and quantification are restricted to small areas. Because spatial and time variability affect emissions, tools need to be developed to predict fCO2 for large areas. This study aimed to investigate soil magnetic susceptibility (MS) and its correlation with fCO2 in an agricultural environment. The experiment was carried out on a Typic Eutrudox located in Guariba-SP, Brazil. Results showed that there was negative spatial correlation between fCO2 and the magnetic susceptibility of Air Dried Soil (MSADS) up to 34.3 m distant. However, the fCO2 had no significant correlation with MSADS, magnetic susceptibility of sand (MSSAND) nor clay (MSCLAY). However, MSADS could be a supplemental mean of identifying regions of high fCO2 potential over large areas.(AU)

Field-scale spatial correlation between contents of iron oxides and CO2 emission in an Oxisol cultivated with sugarcane

Soil CO2 emission (FCO2) is one of the main sources of carbon release into the atmosphere. Moreover, FCO2 is related to soil attributes governing the transfer of gases from soil to the atmosphere. This study aimed firstly to describe the spatial variability of hematite (Hm), goethite (Gt), iron extracted with sodium dithionite-citrate-bicarbonate (Fed) contents, soil CO2 emission (FCO2) and free-water porosity (FWP) and secondly, to develop statistical models to predict the above mentioned factors in an Oxisol cultivated under manual harvesting of sugarcane (Saccharumspp.) in southeastern Brazil. The study was conducted on an irregular 50 m × 50 m grid containing 89 points, each 0.5-10 m apart. The 0-0.1 m soil layer at each sampling point was used to assess soil FCO2, moisture and total pore volume. The results were subjected to descriptive statistical and geostatistical analyses using auto- and cross-semivariograms. All soil attributes exhibited a spatial dependence structure and the experimental semivariograms fitted spherical and exponential models. The Gt content was the individual attribute that exhibited the highest linear and spatial correlation, especially with FCO2. We were able to use diffuse reflectance spectroscopy to map large areas, which allows for easy identification and estimation of soil attributes such as FCO2 and FWP. Geostatistical techniques faciltate the interpretation of spatial relationships between soil respiration and the examined properties.

Field-scale spatial correlation between contents of iron oxides and CO2 emission in an Oxisol cultivated with sugarcane

Soil CO2 emission (FCO2) is one of the main sources of carbon release into the atmosphere. Moreover, FCO2 is related to soil attributes governing the transfer of gases from soil to the atmosphere. This study aimed firstly to describe the spatial variability of hematite (Hm), goethite (Gt), iron extracted with sodium dithionite-citrate-bicarbonate (Fed) contents, soil CO2 emission (FCO2) and free-water porosity (FWP) and secondly, to develop statistical models to predict the above mentioned factors in an Oxisol cultivated under manual harvesting of sugarcane (Saccharumspp.) in southeastern Brazil. The study was conducted on an irregular 50 m × 50 m grid containing 89 points, each 0.5-10 m apart. The 0-0.1 m soil layer at each sampling point was used to assess soil FCO2, moisture and total pore volume. The results were subjected to descriptive statistical and geostatistical analyses using auto- and cross-semivariograms. All soil attributes exhibited a spatial dependence structure and the experimental semivariograms fitted spherical and exponential models. The Gt content was the individual attribute that exhibited the highest linear and spatial correlation, especially with FCO2. We were able to use diffuse reflectance spectroscopy to map large areas, which allows for easy identification and estimation of soil attributes such as FCO2 and FWP. Geostatistical techniques faciltate the interpretation of spatial relationships between soil respiration and the examined properties.(AU)

Incertezas na estimativa da variabilidade espacial da emissão de CO2 do solo e propriedades edáficas em área de cana crua

A emissão de CO2 do solo (FCO2) apresenta alta variabilidade espacial, sendo devida a grande dependência espacial existente nas propriedades do solo que a influenciam. Neste estudo objetivou-se (i) caracterizar e relacionar a variabilidade e a distribuição espacial da FCO2, temperatura do solo, porosidade livre de água (PLA), teor de matéria orgânica do solo (MO) e densidade do solo (Ds), (ii) avaliar a acurácia dos resultados fornecidos pelo método da krigagem ordinária (KO) e simulação sequencial Gaussiana (SSG), e (iii) avaliar a incerteza na predição da variabilidade espacial das FCO2 e demais propriedades utilizando a SSG. O estudo foi conduzido em uma malha amostral regular de 60 x 60 m2 com 141 pontos, com espaçamento mínimo variando de 0,50 a 10 m, instalada em área de cana-de-açúcar. Nestes pontos foram avaliados a FCO2, temperatura do solo, PLA, determinadas com base na média de 07 dias de avaliação, MO e Ds. Todas as variáveis apresentaram estrutura de dependência espacial, sendo ajustados modelos Gaussianos, esféricos e exponenciais. A configuração da malha amostral e possivelmente a presença de espessa camada de resíduos da cultura sobre o solo influenciaram a estrutura de variabilidade espacial da FCO2, temperatura e MO. FCO2 apresentou correlações positivas com a MO (r = 0,25, p < 0,05) e PLA (r = 0,27, p < 0,01) e negativa com a Ds (r = - 0,41, p < 0,01). No entanto, quando os valores digitais estimados espacialmente (N=8.833) são considerados, a PLA passa a ser a principal variável responsável pelas características espaciais da FCO2, apresentando correlação de 0,26 (p < 0,01). As simulações individuais propiciaram, para todas as variáveis analisadas, melhor reprodução das funções de distribuição acumuladas (fdac), e dos variogramas em comparação...

The soil CO2 emission (FCO2) has high spatial variability, which caused due to the strong spatial dependence in soil properties that influence it. This study aimed to (i) to characterize the variability and spatial distribution of FCO2, soil temperature, air-filled pore space (AFPS), soil organic matter (OM) and soil bulk density (BD) and related properties, (ii) evaluate the accuracy of the results provided by the method of ordinary kriging (OK) and sequential Gaussian simulation (SGS), and (iii) evaluate the uncertainty in predicting the spatial variability of FCO2 and other properties using the SSG. The study was conducted on an regular sampling grid with 141 points, with spacing ranging from 0.50 to 10 m, installed in a sugarcane area. In this place were evaluated FCO2, soil temperature, AFPS, were based on the average of 07 days of evaluation, OM and BD. All variables showed spatial dependence structure, and models adjusted Gaussian, spherical and exponential. The configuration of the sampling grid and the presence of intense layer of crop residues in the soil influenced the structure of spatial variability of FCO2, temperature, and OM. The FCO2 showed positive correlations with OM (r = 0.25, p <0.05) and AFPS (r = 0.27, p <0.01) and negatively with Ds (r = - 0.41, p <0.01). However, when the estimated spatially values are considered, the AFPS becomes the main variable responsible for the spatial characteristics of FCO2, showing correlation of 0.26 (p <0.01). The individual simulations led to all variables, better reproduction of the cumulative distribution functions (cdf), and variograms compared to OK and E-type estimate. The analysis results show strong similarities between the E-type estimates to those generated by the procedure of OK. The major uncertainties in predicting FCO2 were associated with areas with the highest...

Color parameters applied to pedotransfer functions in the estimation of soil attributes / Parâmetros da cor aplicados a funções de pedotransferência na estimativa de atributos do solo

Global demands for an increased food production have prompted scientists to create technological innovations in various segments of the agricultural and environmental sectors. The use of diffuse reflectance spectroscopy in soil color determination to estimate its attributes is an example of these advances. Thus, the aim of this research was to identify the potential of the three parameters of the Munsell color system (Hue, Value, and Chroma) in estimating different chemical and particle size attributes by pedotransfer functions in a Typic Hapludox in the Cerrado of Piauí State, Brazil. This soil showed a yellowish color due to the goethite and low contents of bases and organic carbon. Among the calibrated pedotransfer functions, we observed that phosphorus, aluminum, hydrogen, potential acidity, potential cation exchange capacity, and base saturation could be estimated by Hue, while clay content by Value, and Chroma used to estimate hydrogen, potential acidity, and cation exchange capacity. We conclude that the parameter color could be used to estimate soil attributes.

As demandas mundiais por aumento na produção de alimentos vêm instigando os cientistas a criarem inovações tecnológicas em vários segmentos dos setores agrícolas e ambientais. O uso da espectroscopia de reflectância difusa na determinação da cor do solo para a estimativa de seus atributos é um exemplo destes avanços. Assim, objetivou-se com esta pesquisa identificar o potencial dos três parâmetros do sistema Munsell de cores (Matiz, Valor e Croma) em estimar diferentes atributos químicos e granulométricos por funções de pedotransferência, em LATOSSOLO AMARELO Distrófico típico no Cerrado do Estado do Piauí, Brasil. O solo apresentou coloração amarelada, como reflexo da goethita e também baixos teores de bases e carbono orgânico. Dentre as funções de pedotransferência calibradas, observamos que fósforo, alumínio, hidrogênio, acidez potencial, capacidade de troca catiônica potencial e saturação por bases podem ser estimada pela matiz, enquanto o teor de argila pode ser estimada pelo valor e o croma pode ser usado para estimar também hidrogênio, acidez potencial e capacidade de troca catiônica. Concluímos que é possível usar a cor para estimar atributos do solo.