The production of the main soil greenhouse gases (GHG: CO2, CH4 and N2O) is influenced by agricul... more The production of the main soil greenhouse gases (GHG: CO2, CH4 and N2O) is influenced by agricultural practices that causes changes in soil physical, chemical and biological attributes, directly affecting their emission to the atmosphere. The aim of this study was to investigate the infield soil CO2 emissions (FCO2) and the soil CO2, CH4 and N2O production potentials (PCO2, PCH4 and PN2O, respectively) in laboratory conditions, and their relationship to soil attributes in a mechanically harvested sugarcane area. The experimental area consisted of a 50 × 50-m radially symmetrical grid containing 133 points spaced at minimum distances of 0.5 m in the center of the sample grid. It was carried out eight evaluations of FCO2, soil temperature and soil moisture over a period of 19 days. Soil physical and chemical attributes were determined by sampling at a depth of 0–10 cm. The quantification of PCO2, PCH4 and PN2O consisted of laboratory incubation and determination of gas concentration ...
The spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different f... more The spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different factors in a highly complex way. In this context, this study aimed to characterize the spatial variability patterns of FCO2 and soil physical, chemical, and microbiological attributes in a sugarcane field area after reform activities. The study was conducted in an Oxisol with the measurement of FCO2, soil temperature (Ts), and soil moisture (Ms) in a regular 90 × 90-m grid with 100 sampling points. Soil samples were collected at each sampling point at a depth of 0–0.20 m to determine soil physical (density, macroporosity, and microporosity), particle size (sand, silt, and clay), and chemical attributes (soil organic matter, pH, P, K, Ca, Mg, Al, H + Al, cation exchange capacity, and base saturation). Geostatistical analyses were performed to assess the spatial variability and map soil attributes. Two regions (R1 and R2) with contrasting emission values were identified after mapping FCO2. ...
Soil CO2 emission (FCO2) in agricultural areas results from the interaction of different factors ... more Soil CO2 emission (FCO2) in agricultural areas results from the interaction of different factors such as climate and soil conditions. Our objective was to investigate the spatiotemporal variation of FCO2, temperature (Tsoil), moisture (Msoil) and air‐filled pore space (AFPS), as well as their interactions, during the sugarcane field reform. The study was conducted on a 90 × 90 m sampling grid with 100 points at 10 m spacings. Ten assessments of FCO2, Tsoil and Msoil were carried out at each point over a 28‐day period. The greatest mean values of FCO2 (0.74 g m−2 hr−1) and Msoil (31.7%) were obtained on Julian day 276, 2013, being associated with precipitation events at the study site. Also, the smallest values of AFPS (19.17%) and Tsoil (20.90°C) were observed on the same day. The spatial variability of FCO2, Tsoil, Msoil and AFPS was best described by an adjusted spherical model, although an exponential model better fitted some results. The spatial pattern of all soil attributes sh...
Mitigation and Adaptation Strategies for Global Change, 2018
This study aimed to characterize soil carbon dioxide (CO 2) emission associated with soil pore di... more This study aimed to characterize soil carbon dioxide (CO 2) emission associated with soil pore distribution in an Oxisol and Ultisol under chiseling in the planting row and in total area for sugarcane (Saccharum officinarum) cultivation. The experimental design was a large paired-plot design. Treatments consisted of chiseling in the planting row (CPR) and chiseling in total area (CTA) in an Oxisol and Ultisol. Soil CO 2 emission, soil temperature, and soil moisture were assessed over 12 days in the Oxisol and 11 days in the Ultisol at a depth of 0-0.10 m. Organic carbon associated with minerals (OCAM) and particulate organic carbon (POC) were also assessed. OCAM, pore class C2 (0.05 ≤ ɸ < 0.1 mm), soil moisture, and soil temperature explained 72 and 53% of the variability of soil CO 2 emission in CPR and CTA, respectively. In the Ultisol, pore class C1 (ɸ ≥ 0.1 mm) and OCAM explained 82% of the variability of soil CO 2 emission in CPR. In CTA, soil moisture, OCAM, and POC explained 67% of the variability of soil CO 2 emission. In the Oxisol, CPR and CTA affected soil structure, causing changes in both soil porosity and soil CO 2 emission. In the Oxisol, the lowest average value of soil CO 2 emission (2.8 μmol m −2 s −1) was observed in CPR whereas its highest value (3.4 μmol m −2 s −1) was observed in CTA. In the Ultisol, soil tillage (CPR and CTA) did not affect soil CO 2 emission. These results indicate that the intensity of soil tillage in more clayey textured soils favors soil CO 2 emission possibly due to a higher carbon availability for microbial activity when compared to more sandy textured soils. A less intensive soil tillage can be considered as an efficient strategy to reduce soil CO 2 emission and hence soil organic carbon losses. Thus, this management strategy proved to be efficient in terms of mitigating greenhouse gas emissions, reducing the contribution of agriculture to global climate change.
Agriculture is a great emission source of CO 2 into the atmosphere, contributing significantly to... more Agriculture is a great emission source of CO 2 into the atmosphere, contributing significantly to the greenhouse effect. Considering the hypothesis that there are differences in soil carbon dynamics due to the distinct physiological and morphological characteristics of sugarcane cultivars, the aim of this study was to characterize the short-term soil CO 2 emission associated with soil attributes in agricultural areas under cultivation of five sugarcane cultivars. The experiment was conducted in an area of high-clay Oxisol (Hapludox, USDA Soil Taxonomy) located at the Cerrado biome, Midwestern region of Brazil. Over the course of 20 days, ten measurements of soil CO 2 emission (FCO 2), soil temperature (Ts), and soil moisture (Ms) were carried out. Subsequently, soil samples were collected at a depth of 0-0.20 m to determine soil physical and chemical attributes. In timescale, FCO 2 , Ts, and Ms varied depending on the amount of straw produced by each cultivar. The cultivars RB935608, RB935744, and SP832847 induced a higher soil CO 2 emission since they are associated with controlling factors of the primary CO 2 production process (higher organic matter content and lower C/N ratio in the soil). Thus, strategies to reduce greenhouse gas emissions in agriculture, such as the choice of sugarcane cultivars that provide lower soil CO 2 emissions, are essential to mitigate important environmental issues such as the global warming.
Th e objective was to determine the infl uence of partial cultivation of only the crop row on car... more Th e objective was to determine the infl uence of partial cultivation of only the crop row on carbon dioxide (CO 2) emissions in an Oxisol and Ultisol. Th e experimental design was a large pairedplot design with treatments consisting of targeted chiseling to only the planting row to chiseling the whole fi eld. Soil CO 2 emissions, soil temperature, and soil moisture were measured daily for 12 d aft er tillage. In the Oxisol, CO 2 emissions were higher on the second day aft er tillage and then decreased until Day 6. When analyzing the eff ect of tillage, chiseling in the planting row (CPR) showed, in general, lower CO 2 emissions (2.54 µmol m-2 s-1) when compared to chiseling in total area (CTA) (3.32 µmol m-2 s-1), regardless of the day aft er tillage. However, the linear regression analysis between soil CO 2 emissions and soil moisture in the Ultisol was signifi cant for CPR (R 2 = 0.79, p < 0.01) and CTA (R 2 = 0.58, p < 0.01). Total soil CO 2 emissions were higher in the Oxisol for both tillage systems (CPR = 1020.9 kg CO 2 ha-1 and CTA = 1336.3 kg CO 2 ha-1) than the Ultisol (CPR = 587.0 kg CO 2 ha-1 and CTA = 649.3 kg CO 2 ha-1). Th ese results indicate that soil tillage by using CPR favors a lower soil CO 2 emission to the atmosphere and contributes to a reduction in soil degradation when cultivated with sugarcane (Saccharum offi cinarum L.).
Th e economic damage to Brazilian soybean [Glycine max (L.) Merr.] production attributed to Praty... more Th e economic damage to Brazilian soybean [Glycine max (L.) Merr.] production attributed to Pratylenchus brachyurus has increased in recent years. Th e objective of this study was to determine the infl uence of soil properties on nematode variability in a soybean crop. Soil and root samples (0-0.20 m) were collected from 142 points in an area that was 180 by 180 m. Root samples were analyzed for nematodes, and soil samples were analyzed for chemical attributes. Th e data were analyzed using principal component analysis and geostatistics. Th e spatial variability maps of the attributes S, Ca, Mg, K, sum of bases, base saturation index, and cation exchange capacity were aligned with the water runoff direction. Soil organic matter and K were associated with very low number of nematodes in the root (NNR) (NNR £ 3614), low (3614 < NNR £ 10,496), and moderate (10,496 < NNR £ 21,248). On the other hand, the regions with high Mg, S, and soybean productivity were associated with regions with high (21,248 < NNR £ 43,648) and very high (NNR > 43,648) NNR. Th e fi ndings indicated that soil chemical characteristics infl uence the population dynamics of the root-lesion nematode P. brachyurus.
Nas últimas décadas, o tema sustentabilidade passou a ser amplamente discutido em todas as esfera... more Nas últimas décadas, o tema sustentabilidade passou a ser amplamente discutido em todas as esferas da sociedade civil. A conscientização ambiental, crescente ao redor do mundo, fez com que aumentasse a cobrança da sociedade para que as empresas busquem minimizar seus impactos ao meio ambiente onde está inserida. Por esse motivo, as empresas começaram a buscar formas de divulgar para as partes interessadas suas ações relacionadas à sustentabilidade, dando transparência às ações da organização. Nesse sentido, o objetivo deste estudo foi analisar o desempenho ambiental de uma empresa do setor de alimentos, higiene e limpeza (Unilever) a partir da análise de seus relatórios de sustentabilidade divulgados entre 2009 e 2012. A abordagem metodológica foi qualitativa, suportada pela técnica de análise de conteúdo. Para tanto, utilizou-se como estrutura de análise o modelo do Global Reporting Initiative e as classificações de informações propostas por Gasparino e Ribeiro (2007). Foi observad...
Revista Brasileira de Engenharia Agrícola e Ambiental, 2015
O preparo mecânico do solo é uma das práticas agrícolas que contribuem para o aumento da perda de... more O preparo mecânico do solo é uma das práticas agrícolas que contribuem para o aumento da perda de carbono via emissão de CO2 do solo (FCO2). Com este trabalho objetivou-se investigar o efeito de três sistemas de preparo do solo na FCO2, temperatura e umidade do solo em área de reforma da cultura de cana-de-açúcar. A área experimental foi constituída de três parcelas, cada uma recebendo um dos preparos do solo: preparo convencional (PC), subsolagem convencional (SC) e subsolagem localizada (SL). A FCO2, temperatura e a umidade do solo foram avaliadas durante o período total de 17 dias. A FCO2 foi maior no preparo PC (0,75 g CO2 m-2 h-1). A temperatura do solo não diferiu (p > 0,05) entre as subsolagens: SL (26,2 ºC) e SC (25,9 ºC). A umidade do solo foi maior na SL (24%), seguida pela SC (21,8%) e preparo PC (18,3%). Apenas no preparo PC foi observada correlação significativa (r = –0,71; p < 0,05) entre FCO2 e a temperatura do solo. O preparo PC apresentou emissão total (2.864,...
Anais do II Simpósio de Geoestatística Aplicada em Ciências Agrárias, 2011
Avaliação da krigagem ordinária e simulação sequencial gaussiana na interpolação da emissão de CO... more Avaliação da krigagem ordinária e simulação sequencial gaussiana na interpolação da emissão de CO 2 do solo.
Soil CO 2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk densit... more Soil CO 2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.
Soil CO 2 emission (F CO 2) is influenced by chemical, physical and biological factors that affec... more Soil CO 2 emission (F CO 2) is influenced by chemical, physical and biological factors that affect the production of CO 2 in the soil and its transport to the atmosphere. F CO 2 varies in time and space depending on environmental conditions, including the management of the agricultural area. The aim of this study was to investigate the spatial variability structure of F CO 2 and soil attributes in a mechanically harvested sugarcane area (green harvest) using fractal dimension (D F) derived from isotropic variograms at different scales (fractograms). F CO 2 showed an overall average of 1.51 mol CO 2 m −2 s −1 and correlated significantly (P < 0.05) with soil physical attributes, such as soil bulk density, air-filled pore space, macroporosity and microporosity. Topologically significant D F values were obtained from the characterization of F CO 2 at medium and large scales (above 20 m), with values of 2.92 and 2.90, respectively. The variations in D F with scales indicate that the spatial variability structure of F CO 2 was similar to that observed for soil temperature and total pore volume and was the inverse of that observed for other soil attributes, such as soil moisture, soil bulk density, microporosity, air-filled pore space, silt and clay content, pH, available phosphorus and the sum of bases. Thus, the spatial variability structure of F CO 2 presented a significant relationship with the spatial variability structure for most soil attributes, indicating the possibility of using fractograms as a tool to better describe the spatial dependence of variables along the scale.
ABSTRACT The characterization of soil CO2 emissions (FCO2) is important for the study of the glob... more ABSTRACT The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60 m × 60 m containing 127 points with minimum separation distances from 0.5 to 10 m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28 ± 0.11 μmol m−2 s−1 (F197) to 1.82 ± 0.07 μmol m−2 s−1 (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity.
The soil CO2 emission has high spatial variability because it depends strongly on soil properties... more The soil CO2 emission has high spatial variability because it depends strongly on soil properties. The purpose of this study was to (i) characterize the spatial variability of soil respiration and related properties, (ii) evaluate the accuracy of results of the ordinary kriging method and sequential Gaussian simulation, and (iii) evaluate the uncertainty in predicting the spatial variability of soil CO2 emission and other properties using sequential Gaussian simulations. The study was conducted in a sugarcane area, using a regular sampling grid with 141 points, where soil CO2 emission, soil temperature, air-filled pore space, soil organic matter and soil bulk density were evaluated. All variables showed spatial dependence structure. The soil CO2 emission was positively correlated with organic matter (r = 0.25, p < 0.05) and air-filled pore space (r = 0.27, p < 0.01) and negatively with soil bulk density (r = -0.41, p < 0.01). However, when the estimated spatial values were ...
The production of the main soil greenhouse gases (GHG: CO2, CH4 and N2O) is influenced by agricul... more The production of the main soil greenhouse gases (GHG: CO2, CH4 and N2O) is influenced by agricultural practices that causes changes in soil physical, chemical and biological attributes, directly affecting their emission to the atmosphere. The aim of this study was to investigate the infield soil CO2 emissions (FCO2) and the soil CO2, CH4 and N2O production potentials (PCO2, PCH4 and PN2O, respectively) in laboratory conditions, and their relationship to soil attributes in a mechanically harvested sugarcane area. The experimental area consisted of a 50 × 50-m radially symmetrical grid containing 133 points spaced at minimum distances of 0.5 m in the center of the sample grid. It was carried out eight evaluations of FCO2, soil temperature and soil moisture over a period of 19 days. Soil physical and chemical attributes were determined by sampling at a depth of 0–10 cm. The quantification of PCO2, PCH4 and PN2O consisted of laboratory incubation and determination of gas concentration ...
The spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different f... more The spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different factors in a highly complex way. In this context, this study aimed to characterize the spatial variability patterns of FCO2 and soil physical, chemical, and microbiological attributes in a sugarcane field area after reform activities. The study was conducted in an Oxisol with the measurement of FCO2, soil temperature (Ts), and soil moisture (Ms) in a regular 90 × 90-m grid with 100 sampling points. Soil samples were collected at each sampling point at a depth of 0–0.20 m to determine soil physical (density, macroporosity, and microporosity), particle size (sand, silt, and clay), and chemical attributes (soil organic matter, pH, P, K, Ca, Mg, Al, H + Al, cation exchange capacity, and base saturation). Geostatistical analyses were performed to assess the spatial variability and map soil attributes. Two regions (R1 and R2) with contrasting emission values were identified after mapping FCO2. ...
Soil CO2 emission (FCO2) in agricultural areas results from the interaction of different factors ... more Soil CO2 emission (FCO2) in agricultural areas results from the interaction of different factors such as climate and soil conditions. Our objective was to investigate the spatiotemporal variation of FCO2, temperature (Tsoil), moisture (Msoil) and air‐filled pore space (AFPS), as well as their interactions, during the sugarcane field reform. The study was conducted on a 90 × 90 m sampling grid with 100 points at 10 m spacings. Ten assessments of FCO2, Tsoil and Msoil were carried out at each point over a 28‐day period. The greatest mean values of FCO2 (0.74 g m−2 hr−1) and Msoil (31.7%) were obtained on Julian day 276, 2013, being associated with precipitation events at the study site. Also, the smallest values of AFPS (19.17%) and Tsoil (20.90°C) were observed on the same day. The spatial variability of FCO2, Tsoil, Msoil and AFPS was best described by an adjusted spherical model, although an exponential model better fitted some results. The spatial pattern of all soil attributes sh...
Mitigation and Adaptation Strategies for Global Change, 2018
This study aimed to characterize soil carbon dioxide (CO 2) emission associated with soil pore di... more This study aimed to characterize soil carbon dioxide (CO 2) emission associated with soil pore distribution in an Oxisol and Ultisol under chiseling in the planting row and in total area for sugarcane (Saccharum officinarum) cultivation. The experimental design was a large paired-plot design. Treatments consisted of chiseling in the planting row (CPR) and chiseling in total area (CTA) in an Oxisol and Ultisol. Soil CO 2 emission, soil temperature, and soil moisture were assessed over 12 days in the Oxisol and 11 days in the Ultisol at a depth of 0-0.10 m. Organic carbon associated with minerals (OCAM) and particulate organic carbon (POC) were also assessed. OCAM, pore class C2 (0.05 ≤ ɸ < 0.1 mm), soil moisture, and soil temperature explained 72 and 53% of the variability of soil CO 2 emission in CPR and CTA, respectively. In the Ultisol, pore class C1 (ɸ ≥ 0.1 mm) and OCAM explained 82% of the variability of soil CO 2 emission in CPR. In CTA, soil moisture, OCAM, and POC explained 67% of the variability of soil CO 2 emission. In the Oxisol, CPR and CTA affected soil structure, causing changes in both soil porosity and soil CO 2 emission. In the Oxisol, the lowest average value of soil CO 2 emission (2.8 μmol m −2 s −1) was observed in CPR whereas its highest value (3.4 μmol m −2 s −1) was observed in CTA. In the Ultisol, soil tillage (CPR and CTA) did not affect soil CO 2 emission. These results indicate that the intensity of soil tillage in more clayey textured soils favors soil CO 2 emission possibly due to a higher carbon availability for microbial activity when compared to more sandy textured soils. A less intensive soil tillage can be considered as an efficient strategy to reduce soil CO 2 emission and hence soil organic carbon losses. Thus, this management strategy proved to be efficient in terms of mitigating greenhouse gas emissions, reducing the contribution of agriculture to global climate change.
Agriculture is a great emission source of CO 2 into the atmosphere, contributing significantly to... more Agriculture is a great emission source of CO 2 into the atmosphere, contributing significantly to the greenhouse effect. Considering the hypothesis that there are differences in soil carbon dynamics due to the distinct physiological and morphological characteristics of sugarcane cultivars, the aim of this study was to characterize the short-term soil CO 2 emission associated with soil attributes in agricultural areas under cultivation of five sugarcane cultivars. The experiment was conducted in an area of high-clay Oxisol (Hapludox, USDA Soil Taxonomy) located at the Cerrado biome, Midwestern region of Brazil. Over the course of 20 days, ten measurements of soil CO 2 emission (FCO 2), soil temperature (Ts), and soil moisture (Ms) were carried out. Subsequently, soil samples were collected at a depth of 0-0.20 m to determine soil physical and chemical attributes. In timescale, FCO 2 , Ts, and Ms varied depending on the amount of straw produced by each cultivar. The cultivars RB935608, RB935744, and SP832847 induced a higher soil CO 2 emission since they are associated with controlling factors of the primary CO 2 production process (higher organic matter content and lower C/N ratio in the soil). Thus, strategies to reduce greenhouse gas emissions in agriculture, such as the choice of sugarcane cultivars that provide lower soil CO 2 emissions, are essential to mitigate important environmental issues such as the global warming.
Th e objective was to determine the infl uence of partial cultivation of only the crop row on car... more Th e objective was to determine the infl uence of partial cultivation of only the crop row on carbon dioxide (CO 2) emissions in an Oxisol and Ultisol. Th e experimental design was a large pairedplot design with treatments consisting of targeted chiseling to only the planting row to chiseling the whole fi eld. Soil CO 2 emissions, soil temperature, and soil moisture were measured daily for 12 d aft er tillage. In the Oxisol, CO 2 emissions were higher on the second day aft er tillage and then decreased until Day 6. When analyzing the eff ect of tillage, chiseling in the planting row (CPR) showed, in general, lower CO 2 emissions (2.54 µmol m-2 s-1) when compared to chiseling in total area (CTA) (3.32 µmol m-2 s-1), regardless of the day aft er tillage. However, the linear regression analysis between soil CO 2 emissions and soil moisture in the Ultisol was signifi cant for CPR (R 2 = 0.79, p < 0.01) and CTA (R 2 = 0.58, p < 0.01). Total soil CO 2 emissions were higher in the Oxisol for both tillage systems (CPR = 1020.9 kg CO 2 ha-1 and CTA = 1336.3 kg CO 2 ha-1) than the Ultisol (CPR = 587.0 kg CO 2 ha-1 and CTA = 649.3 kg CO 2 ha-1). Th ese results indicate that soil tillage by using CPR favors a lower soil CO 2 emission to the atmosphere and contributes to a reduction in soil degradation when cultivated with sugarcane (Saccharum offi cinarum L.).
Th e economic damage to Brazilian soybean [Glycine max (L.) Merr.] production attributed to Praty... more Th e economic damage to Brazilian soybean [Glycine max (L.) Merr.] production attributed to Pratylenchus brachyurus has increased in recent years. Th e objective of this study was to determine the infl uence of soil properties on nematode variability in a soybean crop. Soil and root samples (0-0.20 m) were collected from 142 points in an area that was 180 by 180 m. Root samples were analyzed for nematodes, and soil samples were analyzed for chemical attributes. Th e data were analyzed using principal component analysis and geostatistics. Th e spatial variability maps of the attributes S, Ca, Mg, K, sum of bases, base saturation index, and cation exchange capacity were aligned with the water runoff direction. Soil organic matter and K were associated with very low number of nematodes in the root (NNR) (NNR £ 3614), low (3614 < NNR £ 10,496), and moderate (10,496 < NNR £ 21,248). On the other hand, the regions with high Mg, S, and soybean productivity were associated with regions with high (21,248 < NNR £ 43,648) and very high (NNR > 43,648) NNR. Th e fi ndings indicated that soil chemical characteristics infl uence the population dynamics of the root-lesion nematode P. brachyurus.
Nas últimas décadas, o tema sustentabilidade passou a ser amplamente discutido em todas as esfera... more Nas últimas décadas, o tema sustentabilidade passou a ser amplamente discutido em todas as esferas da sociedade civil. A conscientização ambiental, crescente ao redor do mundo, fez com que aumentasse a cobrança da sociedade para que as empresas busquem minimizar seus impactos ao meio ambiente onde está inserida. Por esse motivo, as empresas começaram a buscar formas de divulgar para as partes interessadas suas ações relacionadas à sustentabilidade, dando transparência às ações da organização. Nesse sentido, o objetivo deste estudo foi analisar o desempenho ambiental de uma empresa do setor de alimentos, higiene e limpeza (Unilever) a partir da análise de seus relatórios de sustentabilidade divulgados entre 2009 e 2012. A abordagem metodológica foi qualitativa, suportada pela técnica de análise de conteúdo. Para tanto, utilizou-se como estrutura de análise o modelo do Global Reporting Initiative e as classificações de informações propostas por Gasparino e Ribeiro (2007). Foi observad...
Revista Brasileira de Engenharia Agrícola e Ambiental, 2015
O preparo mecânico do solo é uma das práticas agrícolas que contribuem para o aumento da perda de... more O preparo mecânico do solo é uma das práticas agrícolas que contribuem para o aumento da perda de carbono via emissão de CO2 do solo (FCO2). Com este trabalho objetivou-se investigar o efeito de três sistemas de preparo do solo na FCO2, temperatura e umidade do solo em área de reforma da cultura de cana-de-açúcar. A área experimental foi constituída de três parcelas, cada uma recebendo um dos preparos do solo: preparo convencional (PC), subsolagem convencional (SC) e subsolagem localizada (SL). A FCO2, temperatura e a umidade do solo foram avaliadas durante o período total de 17 dias. A FCO2 foi maior no preparo PC (0,75 g CO2 m-2 h-1). A temperatura do solo não diferiu (p > 0,05) entre as subsolagens: SL (26,2 ºC) e SC (25,9 ºC). A umidade do solo foi maior na SL (24%), seguida pela SC (21,8%) e preparo PC (18,3%). Apenas no preparo PC foi observada correlação significativa (r = –0,71; p < 0,05) entre FCO2 e a temperatura do solo. O preparo PC apresentou emissão total (2.864,...
Anais do II Simpósio de Geoestatística Aplicada em Ciências Agrárias, 2011
Avaliação da krigagem ordinária e simulação sequencial gaussiana na interpolação da emissão de CO... more Avaliação da krigagem ordinária e simulação sequencial gaussiana na interpolação da emissão de CO 2 do solo.
Soil CO 2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk densit... more Soil CO 2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.
Soil CO 2 emission (F CO 2) is influenced by chemical, physical and biological factors that affec... more Soil CO 2 emission (F CO 2) is influenced by chemical, physical and biological factors that affect the production of CO 2 in the soil and its transport to the atmosphere. F CO 2 varies in time and space depending on environmental conditions, including the management of the agricultural area. The aim of this study was to investigate the spatial variability structure of F CO 2 and soil attributes in a mechanically harvested sugarcane area (green harvest) using fractal dimension (D F) derived from isotropic variograms at different scales (fractograms). F CO 2 showed an overall average of 1.51 mol CO 2 m −2 s −1 and correlated significantly (P < 0.05) with soil physical attributes, such as soil bulk density, air-filled pore space, macroporosity and microporosity. Topologically significant D F values were obtained from the characterization of F CO 2 at medium and large scales (above 20 m), with values of 2.92 and 2.90, respectively. The variations in D F with scales indicate that the spatial variability structure of F CO 2 was similar to that observed for soil temperature and total pore volume and was the inverse of that observed for other soil attributes, such as soil moisture, soil bulk density, microporosity, air-filled pore space, silt and clay content, pH, available phosphorus and the sum of bases. Thus, the spatial variability structure of F CO 2 presented a significant relationship with the spatial variability structure for most soil attributes, indicating the possibility of using fractograms as a tool to better describe the spatial dependence of variables along the scale.
ABSTRACT The characterization of soil CO2 emissions (FCO2) is important for the study of the glob... more ABSTRACT The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60 m × 60 m containing 127 points with minimum separation distances from 0.5 to 10 m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28 ± 0.11 μmol m−2 s−1 (F197) to 1.82 ± 0.07 μmol m−2 s−1 (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity.
The soil CO2 emission has high spatial variability because it depends strongly on soil properties... more The soil CO2 emission has high spatial variability because it depends strongly on soil properties. The purpose of this study was to (i) characterize the spatial variability of soil respiration and related properties, (ii) evaluate the accuracy of results of the ordinary kriging method and sequential Gaussian simulation, and (iii) evaluate the uncertainty in predicting the spatial variability of soil CO2 emission and other properties using sequential Gaussian simulations. The study was conducted in a sugarcane area, using a regular sampling grid with 141 points, where soil CO2 emission, soil temperature, air-filled pore space, soil organic matter and soil bulk density were evaluated. All variables showed spatial dependence structure. The soil CO2 emission was positively correlated with organic matter (r = 0.25, p < 0.05) and air-filled pore space (r = 0.27, p < 0.01) and negatively with soil bulk density (r = -0.41, p < 0.01). However, when the estimated spatial values were ...
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Papers by Elton Bicalho