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Saflufenacil is a herbicide recommended for use in the main agricultural crops in Brazil to control eudicotyledonous weeds. However, the application of saflufenacil has been carried out without previous knowledge of this herbicide interactions with soil colloids, which may increase environmental contamination risks. In this study, the leaching of saflufenacil in soil samples was estimated with different organic matter contents. Therefore, PVC columns were filled with samples of Xanthic Ferralsol (XF) and Ferralsol (F), with different physical and chemical attributes. Twelve hours after herbicide (70 g i.a. ha-1) application, the PVC columns were subjected to a rainfall of 60 mm. For the evaluation of saflufenacil leaching, the columns were sectioned in ten parts with 5-cm each. Saflufenacil leached up to 50 and 40 cm deep in the samples, with the lowest contents of organic matter of XF and F, respectively. The increase in organic matter content of Ferralsol and Xanthic Ferralsol samples reduced saflufenacil leaching and the symptoms of intoxication in the indicator species. There was an inverse relation between the content of organic matter and the leaching of the herbicide in both soils studied. It was observed that the application of saflufenacil in soils with low organic matter contents may represent a significant environmental contamination risk of soils and watercourses.

The use of herbicides belonging to a single mechanism of action for several consecutive years in the same area may lead to the selection of weed biotypes resistant to herbicides. Weeds resistant to glyphosate have been problem worldwide. As an alternative control, farmers have used glyphosate mixed with sulfentrazone. When two herbicides are mixed, the parameters that govern the behaviour of herbicides in the soil can be altered. In this study, the sorption of sulfentrazone was estimated when applied in isolation with glyphosate formulations. For this, increasing doses of sulfentrazone were applied using Red-Yellow Latosol substrate and washed sand. Each dose of sulfentrazone was applied in a mixture with 1080 g a. e. ha-1 Roundup Ready®, Roundup Ultra® and Zapp Qi®. To evaluate the presence of sulfentrazone in the soil solution, Sorghum bicolor was used as an indicator species. Symptoms of intoxication were evaluated at 7, 14 and 21 days after sowing. At 21 days after sowing, the plants were collected and dried in an oven at 70 ± 10 °C to determine the dry matter. Based on the intoxication of the indicator plants, it was verified that, regardless of the formulation, the presence of glyphosate in the mixture increased the sorption of sulfentrazone in the Red-Yellow Latosol. However, based on dry matter accumulation, sulfentrazone sorption increased because of the mixture with Roundup Ultra®, but decreased due to the presence of Roundup Ready® and Zapp Qi®. Therefore, the application of sulfentrazone in mixture with glyphosate alters the sorptive forces of sulfentrazone in a Red-Yellow Latosol.

The use of herbicides belonging to a single mechanism of action for several consecutive years in the same area may lead to the selection of weed biotypes resistant to herbicides. Weeds resistant to glyphosate have been problem worldwide. As an alternative control, farmers have used glyphosate mixed with sulfentrazone. When two herbicides are mixed, the parameters that govern the behaviour of herbicides in the soil can be altered. In this study, the sorption of sulfentrazone was estimated when applied in isolation with glyphosate formulations. For this, increasing doses of sulfentrazone were applied using Red-Yellow Latosol substrate and washed sand. Each dose of sulfentrazone was applied in a mixture with 1080 g a. e. ha-1 Roundup Ready®, Roundup Ultra® and Zapp Qi®. To evaluate the presence of sulfentrazone in the soil solution, Sorghum bicolor was used as an indicator species. Symptoms of intoxication were evaluated at 7, 14 and 21 days after sowing. At 21 days after sowing, the plants were collected and dried in an oven at 70 ± 10 °C to determine the dry matter. Based on the intoxication of the indicator plants, it was verified that, regardless of the formulation, the presence of glyphosate in the mixture increased the sorption of sulfentrazone in the Red-Yellow Latosol. However, based on dry matter accumulation, sulfentrazone sorption increased because of the mixture with Roundup Ultra®, but decreased due to the presence of Roundup Ready® and Zapp Qi®. Therefore, the application of sulfentrazone in mixture with glyphosate alters the sorptive forces of sulfentrazone in a Red-Yellow Latosol.

Sweet sorghum is currently an important alternative for ethanol production in sugar cane off-season. In this study was to evaluate the effects of plant arrangements and the application of atrazine and S-metolachlor on growth and productivity of sweet sorghum. An experiment was conducted in randomized block design and, arranged in split plots with four repetitions. Plots consisted of spacing (0.25 m, 0.45 m 0.45-0.45-0.90 m) and sub-plots of weed control methods - atrazine (2000 g ha-1), atrazine + S-metolachlor (2000 + 720 g ha-1), atrazine + S-metolachlor (2000 + 960 g ha-1), atrazine + S-metolachlor (2000 + 1200 g ha-1), atrazine + S-metolachlor (2000 + 1440 g ha-1). Besides that, manual hoeing control was added. The intoxication of sorghum plants and weed control was evaluated at 7, 14 e 28 days after herbicides application (DAA). Plant height, stem diameter, total fresh matter, juice mass and total soluble solids (°Brix) were evaluated at 120 days after crop emergence (DAE). There was no interaction between the factors spacings and control method for variables total matter fresh (TMF), height (H), stem diameter (D), juice mass (JM), and Brix. Application of the mixture (atrazine + S-metolachlor) in the highest doses reduced total fresh matter and °Brix. The spacing of 0.25 m provided the highest productivity of fresh matter, juice mass and increased the °Brix. The application of mixture (atrazine + S-metolachlor) controlled 90% of the weeds at 28 days after application. The increasing in doses of S-metolachlor elevates the intoxication in sorghum plants. The mixture (atrazine + S-metolachlor) has a potential for use in weed control in sweet sorghum, but at doses below 960 g ha-1 of S-metolachlor. metolachlor.

Sweet sorghum is currently an important alternative for ethanol production in sugar cane off-season. In this study was to evaluate the effects of plant arrangements and the application of atrazine and S-metolachlor on growth and productivity of sweet sorghum. An experiment was conducted in randomized block design and, arranged in split plots with four repetitions. Plots consisted of spacing (0.25 m, 0.45 m 0.45-0.45-0.90 m) and sub-plots of weed control methods - atrazine (2000 g ha-1), atrazine + S-metolachlor (2000 + 720 g ha-1), atrazine + S-metolachlor (2000 + 960 g ha-1), atrazine + S-metolachlor (2000 + 1200 g ha-1), atrazine + S-metolachlor (2000 + 1440 g ha-1). Besides that, manual hoeing control was added. The intoxication of sorghum plants and weed control was evaluated at 7, 14 e 28 days after herbicides application (DAA). Plant height, stem diameter, total fresh matter, juice mass and total soluble solids (°Brix) were evaluated at 120 days after crop emergence (DAE). There was no interaction between the factors spacings and control method for variables total matter fresh (TMF), height (H), stem diameter (D), juice mass (JM), and Brix. Application of the mixture (atrazine + S-metolachlor) in the highest doses reduced total fresh matter and °Brix. The spacing of 0.25 m provided the highest productivity of fresh matter, juice mass and increased the °Brix. The application of mixture (atrazine + S-metolachlor) controlled 90% of the weeds at 28 days after application. The increasing in doses of S-metolachlor elevates the intoxication in sorghum plants. The mixture (atrazine + S-metolachlor) has a potential for use in weed control in sweet sorghum, but at doses below 960 g ha-1 of S-metolachlor. metolachlor.

The knowledge of the processes that affect soil herbicide behavior allows to developing practices that improve efficiency in chemical weed control and reduce the negative impacts of cropping-systems. In this research, we used HPLC to determine sorption and desorption of clomazone in Brazilian soil samples (Red-Yellow Latosol with liming and without liming, Red latosol with and without liming, and Organosol). To study clomazone sorption, we used the batch equilibrium method. Clomazone concentrations in soil samples were determined by HPLC. Desorption was quantitated using the samples contained in tubes after sorption testing, repeating the steps followed to quantify sorption. The Freundlich isotherm adequately describe clomazone sorption in all soils. Variation in pH in Red-Yellow Latosol and Red Latosol did not change clomazone sorption. The values of the Freundlich constant (Kf) indicate that clomazone sorption is higher in Organosol, followed by Red latosol (with liming) = Red latosol (without liming) > Red-Yellow Latosol (with liming) = Red-Yellow Latosol (without liming). We conclude that among the attributes evaluated, soil organic matter has the highest impact on clomazone sorption. There was a direct relationship between Kf values and organic matter content of the substrates. Desorption of clomazone was very low in the evaluated soils, with the exception of Organosol, where quantification of the herbicide was possible.

The knowledge of the processes that affect soil herbicide behavior allows to developing practices that improve efficiency in chemical weed control and reduce the negative impacts of cropping-systems. In this research, we used HPLC to determine sorption and desorption of clomazone in Brazilian soil samples (Red-Yellow Latosol with liming and without liming, Red latosol with and without liming, and Organosol). To study clomazone sorption, we used the batch equilibrium method. Clomazone concentrations in soil samples were determined by HPLC. Desorption was quantitated using the samples contained in tubes after sorption testing, repeating the steps followed to quantify sorption. The Freundlich isotherm adequately describe clomazone sorption in all soils. Variation in pH in Red-Yellow Latosol and Red Latosol did not change clomazone sorption. The values of the Freundlich constant (Kf) indicate that clomazone sorption is higher in Organosol, followed by Red latosol (with liming) = Red latosol (without liming) > Red-Yellow Latosol (with liming) = Red-Yellow Latosol (without liming). We conclude that among the attributes evaluated, soil organic matter has the highest impact on clomazone sorption. There was a direct relationship between Kf values and organic matter content of the substrates. Desorption of clomazone was very low in the evaluated soils, with the exception of Organosol, where quantification of the herbicide was possible.

New paradigms of Brazilian dental education involve orthodontics in the context of generalist professional formation, encouraging the recognition of teaching reality of this discipline in undergraduate courses in dentistry. This article discusses the orthodontics discipline in Brazilian dentistry undergraduate courses to identify the number of semesters offered, nomenclature, insertion model, content format and the performance of clinical practice in undergraduate education and its association with characterization variables of the discipline. Electronic questionnaires were sent to 203 dental schools, 55 public and 148 private, registered to the Federal Council of Dentistry in 2013. The questionnaires were answered by 92 teachers of orthodontics, representing 45.3% of the existing dental undergraduate courses in Brazil: 55.4% of which from private and 44.6% public schools. The findings of this research show that orthodontics teaching is present in all undergraduate courses analyzed, is a predominant and integrated subject in pediatric dentistry, addresses the contents in theoretical and practical form both in the laboratory and clinic, and assists children with deciduous and mixed dentition for diagnosis, prevention and interception of malocclusions. Egressed students are able to recognize orthodontic problems and direct these young patients to treatment. The presence of clinical practice was associated with the variables that denote greater investments of higher education institutions in professors, academic credentials and curricular matrix due to the integrality of the contents and course load distribution for the discipline.

New paradigms of Brazilian dental education involve orthodontics in the context of generalist professional formation, encouraging the recognition of teaching reality of this discipline in undergraduate courses in dentistry. This article discusses the orthodontics discipline in Brazilian dentistry undergraduate courses to identify the number of semesters offered, nomenclature, insertion model, content format and the performance of clinical practice in undergraduate education and its association with characterization variables of the discipline. Electronic questionnaires were sent to 203 dental schools, 55 public and 148 private, registered to the Federal Council of Dentistry in 2013. The questionnaires were answered by 92 teachers of orthodontics, representing 45.3% of the existing dental undergraduate courses in Brazil: 55.4% of which from private and 44.6% public schools. The findings of this research show that orthodontics teaching is present in all undergraduate courses analyzed, is a predominant and integrated subject in pediatric dentistry, addresses the contents in theoretical and practical form both in the laboratory and clinic, and assists children with deciduous and mixed dentition for diagnosis, prevention and interception of malocclusions. Egressed students are able to recognize orthodontic problems and direct these young patients to treatment. The presence of clinical practice was associated with the variables that denote greater investments of higher education institutions in professors, academic credentials and curricular matrix due to the integrality of the contents and course load distribution for the discipline.

São poucas as informações na literatura sobre herbicidas para aplicação em pós-emergência da cultura da mandioca e seus possíveis impactos na atividade microbiana do solo. Dessa forma, objetivou-se com este trabalho avaliar o efeito da aplicação de herbicidas pós-emergentes em área total e dirigida na atividade microbiana de solo cultivado com mandioca, bem como seu efeito no controle das plantas daninhas e no crescimento inicial da cultura. O experimento foi conduzido em campo, no Distrito do Planalto, na cidade de Diamantina-MG. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições e os tratamentos foram constituídos de uma testemunha capinada, uma testemunha cultivada sem o controle de plantas daninhas e a aplicação dos herbicidas: fluazifop-p-butil, fomesafen, glyphosate, paraquat e a mistura de herbicidas fluazifop-p-butil + fomesafem. De maneira geral, os herbicidas estudados apresentaram controle satisfatório das plantas daninhas presentes na área de plantio e causaram baixa intoxicação visual à mandioca. A mistura dos herbicidas fomesafen e fluazifop-p-butil promoveram um controle mais prolongado das plantas infestantes, mas com influência negativa à microbiota do solo. Os herbicidas paraquat e glyphosate apresentaram potencial para aplicação dirigida nas entrelinhas da mandioca.