ABSTRACT The pandemic caused by COVID-19 had several impacts on society, especially on health, economic and access to food issues. In this sense, family farming plays an important role in food production, in addition to its socioeconomic contribution. The study aims to identify the marketing strategies of family farming during the pandemic period in the municipality of Dom Pedrito/RS. Methodologically, the study is a qualitative and descriptive research, carried out through interviews with family farmers and consumers in the municipality. To analyze the data collected, content analysis was used. The main results obtained in the study relate to the change in purchasing behavior on the part of consumers, who started to search for their food in fairs in rural properties, where forms of direct contact facilitate the commercialization and the use of technologies serves to subsidize the marketing of food, such as: phone calls, use of social networks and messaging applications, combined with the process of home delivery of purchases and also the need for public policies acting to mitigate the effects of the pandemic.

RESUMO A pandemia provocada pela COVID-19 acarretou diversos impactos na sociedade, com destaque para questões sanitárias, econômicas e de acesso à alimentação. Neste sentido, cabe a categoria agricultura familiar um importante papel na produção de alimentos, além de sua contribuição socioeconômica. O estudo tem como objetivo identificar as estratégias de comercialização da agricultura familiar durante o período de pandemia no município de Dom Pedrito/RS. Metodologicamente, o estudo trata-se de uma pesquisa de abordagem qualitativa e caráter descritivo, realizado através de entrevistas com agricultores familiares e consumidores do município. Para analisar os dados coletados, utilizou-se a análise de conteúdo. Os principais resultados obtidos no estudo dizem respeito à mudança no comportamento de compras por parte dos consumidores, que passaram a buscar seus alimentos em feiras nas propriedades rurais, onde formas de contato direto facilitam a comercialização e o uso de tecnologias serve para subsidiar a comercialização de alimentos, tais como: ligações telefônicas, utilização de redes sociais e aplicativos de mensagens, combinados ao processo de entrega de compras a domicílios e ainda a necessidade de políticas públicas atuando para mitigar os efeitos da pandemia.

O trabalho verificou a possibilidade de inserção das Plantas Alimentícias Não Convencionais na merenda escolar no município de Dom Pedrito, RS. Buscou-se compreender como ocorre a articulação do Programa Nacional de Alimentação Escolar em relação as estratégias de segurança alimentar e nutricional dos alunos. Participaram deste estudo dois gestores municipais e quatro servidores de duas escolas. Foram realizadas entrevistas nos meses de março e abril de dois mil e dezenove. Os resultados foram avaliados a luz da análise textual de discurso. Os resultados apresentam o desconhecimento dos servidores em relação às Panc’s e sua importância como elemento para assegurar segurança alimentar e nutricional, enfatizam a preocupação pela adoção de hábitos alimentares saudáveis, verificou-se o distanciamento entre a participação dos pais para com as atividades realizadas dentro da escola, sinalizando a necessidade da promoção de ações em torno da segurança alimentar, envolvendo todos os atores envolvidos no processo da alimentação na escola.

The work verified the possibility of insertion of Panc's in the school lunch in the municipality of Dom Pedrito, RS. To this end, we sought to understand how the articulation of PNAE occurs in strategies to ensure food and nutritional security of students. Two municipal managers and four employees from two schools participated in this study. In-depth interviews were conducted in March and April 2019. Results were evaluated by textual discourse analysis. The main result shows the lack of knowledge of servers regarding the Panc's and their importance as an element to ensure food and nutritional security. Another result found was the concern for the adoption of healthy eating habits. Verify a detachment between the participation of parents towards activities carried out within the school, signaling the need to promote actions around food safety, involving all actors involved in the school feeding process.

ABSTRACT Aggregate stability is one of the most important factors in soil conservation and maintenance of soil environmental functions. The objective of this study was to investigate the aggregate stability mechanisms related to chemical composition of organic matter in soil profiles with humic and histic horizons in a toposequence under Araucaria moist forest in southern Brazil. The soils sampled were classified as Humic Hapludox (highest position), Fluvaquentic Humaquepts (lowest slope position), and Typic Haplosaprists (floodplain). The C and N contents were determined in bulk soil samples. The chemical composition of soil organic matter was evaluated by infrared spectroscopy. Aggregate stability was determined by applying increasing levels of ultrasound energy. Carbon content increased from the top of the slope to the alluvial plain. Higher ultrasonic energy values for clay dispersion were observed in the C-rich soils in the lower landscape positions, indicating that organic compounds play an important role in the structural stabilization of these profiles. Both aliphatic and carbohydrate-like structures were pertinent to aggregate stability. In the Oxisol, organo-mineral interaction between carbohydrates and the clay mineral surface was the most important mechanism affecting aggregation. In soils with a higher C content (Humaquepts and Haplosaprists), stabilization is predominantly conferred by the aliphatic groups, which is probably due to the structural protection offered by these hydrophobic organic groups.

ABSTRACT Soils with humic and histic horizons in tropical and subtropical ecosystems play an important role in determining the atmospheric C stock and its stabilization, climate regulation, water holding capacity, and environmental filtering, due to the different functions of soil organic matter (SOM). However, the processes and mechanisms that regulate SOM dynamics in these soils are not clear. The objectives of this study were: i) determine the C and N stocks and ii) investigate the SOM chemical fractions and their interactions with Fe and Al ions in soils with humic and histic horizons of a toposequence under Araucaria moist forest in southern Brazil. The soils sampled were classified as Humic Hapludox (top - not hydromorphic), Fluvaquentic Humaquepts (lower third - hydromorphic), and Typic Haplosaprists (floodplain - hydromorphic). The C and N contents were determined in bulk soil samples and SOM chemical fractions; in these fractions, Fe and Al co-extracted contents were also determined. The chemical composition of humin and humic acid fractions was investigated by FTIR spectroscopy. The C content in the toposequence increased from the top to the lowest position. The differences observed in SOM content and SOM chemical composition were defined by the differences in soil water regime. The amount of C stored in the subsurface horizons is about 70 % of total organic C. The carbohydrate-like structures in the humin fraction were protected from solubilization through interaction with iron oxides, which may represent an important mechanism for labile organic compound preservation in these soils. The soluble humic substances showed the highest Fe and Al contents, and their compartments have different affinities for Fe and Al.

RESUMO A interação de compostos orgânicos com minerais de argila pode alterar o tamanho dos cristais. No entanto, em solos, esse efeito é ainda pouco claro por causa das limitações na separação de fases puras de minerais para realizar experimentos de dissolução. Neste estudo, a relação entre a matéria orgânica do solo (MOS) e diâmetro médio do cristal (DMC) de minerais de argila de horizontes superficiais e subsuperfíciais de solos de uma topossequência no sul do Brasil foi avaliada. Os teores de C e N foram determinados, e a natureza dos grupos funcionais da MOS foi avaliada por espectroscopia de FTIR. O DMC dos minerais foi avaliado por difração de raios X, em umas amostras desferrificadas e outras com óxidos de Fe concentrados. Os teores de C e N e as intensidades relativas dos espectros de FTIR foram considerados como variáveis preditoras; e o DMC de hematita, goethita, caulinita e gibbsita, como variáveis preditas. Os teores de C e N e os grupos carboxílicos e C-O-Alquil evidenciaram efeito significativo sobre a variação do DMC. A dimensão dos cristais de óxidos de Fe e de caulinita foi inversamente correlacionada com esses atributos da MOS. Em contraste, o DMC de gibbsita não foi influenciado pelos atributos dae MOS. A influência da MOS sobre o DMC dos óxidos de Fe foi atribuída às reações de complexação de superfície e de redox, que promovem um processo contínuo de dissolução-precipitação.

ABSTRACT The interaction of organic compounds with clay minerals can change the size of crystals. However, in soils this effect is still unclear because of limitations in separation of pure mineral phases for conducting dissolution experiments. In this study, the relationship between soil organic matter (SOM) and mean crystallite size (MCS) of clay minerals from surface and subsurface horizons of soils from a toposequence in Southern Brazil was evaluated. Soil C and N contents were determined and the nature of the SOM functional groups were evaluated by FTIR spectroscopy. The MCS of minerals was assessed by X ray diffraction performed on Fe-oxide free samples and on Fe-concentrated samples. The C and N content and the relative intensities of the FTIR spectra were considered as predictor variables, and the MCS of hematite, goethite, kaolinite, and gibbsite as predicated variables. The C and N content and carboxylic and C-O-alkyl groups showed significant effects on the variation of MCS. The crystallite dimension of the Fe-oxides and kaolinite was inversely affected by these SOM properties. In contrast, the MCS of gibbsite was not affected by the SOM properties. The SOM influence on the MCS of Fe-oxides was attributed to surface complexation reactions and to surface redox reactions that promote a continuous dissolution-precipitation process.