Paulo Henrique da Silva Câmara

The adoption of conservation systems in agriculture has been increasingly explored as a strategy to improve soil quality and potentially influence greenhouse gas (GHG) emissions. This study reports the first assessment of GHG emissions within a long-term (14 years) agroecological field experiment evaluating soil management systems for onion (Allium cepa L.) production in a Humic Dystrudept (Cambissolo Húmico Distrófico, Brazilian Soil Classification System) in Southern Brazil. Three management systems based on permanent soil cover and crop diversification were evaluated in an onion–maize rotation: conventional tillage (CT) without cover crops, no-till (NT) without cover crops, and a no-till vegetable system (NTV) with a summer cover crop mixture of pearl millet (Pennisetum americanum), velvet bean (Mucuna aterrima), and sunflower (Helianthus annuus). Short-term GHG emissions were monitored during one onion growing season (106 days), while soil chemical and physical properties reflect long-term management effects. Evaluations included (i) daily and cumulative GHG (N₂O, CH₄, and CO₂) emissions, (ii) soil carbon (C) and nitrogen (N) stocks, (iii) soil aggregation, porosity, and bulk density in different soil layers (0.00–0.05, 0.05–0.10, and 0.10–0.30 m), and (iv) onion yield and cover crop dry matter production. The NTV system improved soil physical and chemical quality and increased onion yield compared to NT and CT. However, higher cumulative N₂O emissions were observed in NTV, highlighting a short-term trade-off between increased N₂O emissions and long-term improvements in soil quality and crop productivity. All systems acted as methane sinks, with greater CH₄ uptake under NTV. Despite higher short-term emissions, the NTV system maintained a positive C balance due to long-term C accumulation in soil. Short-term greenhouse gas emissions were assessed during a single onion growing season, whereas soil carbon stocks reflect long-term management effects; CO₂ fluxes measured using static chambers represent ecosystem respiration rather than net ecosystem carbon balance. These results provide an initial baseline of GHG dynamics within a long-term agroecological system and support future multi-year assessments aimed at refining mitigation strategies in diversified vegetable production systems.

Vegetable production primarily relies on the conventional tillage system (CTS), which leads to soil degradation through erosion and reduced soil health. The use of no-tillage vegetable systems (NTVS) aims to mitigate these issues; however, information about the impact of this management system on soil health and greenhouse gas (GHG) emissions remains limited. Thus, the objective of this study was to conduct an on-farm evaluation of the effects of no-tillage and cover crop use on soil C and N contents and stocks, soil bulk density (SD), mean geometric diameter (MGD) of aggregates, soil temperature, volumetric soil moisture (VM), plant yield, and GHG emissions in cauliflower production under NTVS compared to CTS in a subtropical ecosystem in southeastern Brazil. Chemical and physical properties were assessed at depths of 0–5, 5–10, and 10–30 cm. GHG emissions, particularly nitrous oxide (N₂O), carbon dioxide (CO₂), and methane (CH₄) were measured using closed static chambers and gas chromatography. NTVS with cover crop mixes had higher yield than CTS without cover crops (25.1 and 18.4 Mg ha⁻¹, respectively). NTVS exhibited increased MGD and VM and reduced SD. Soil temperature in the 0–5 cm layer was lower in NTVS than in CTS. Soil C and N stocks were higher in NTVS, but high N₂O emissions offset this advantage compared to CTS. Overall, NTVS emitted more CO₂ and N₂O than CTS, while both systems showed soil CH₄ uptake. NTVS maintained sufficient carbon equivalent reserves (0–30 cm) to offset GHG emissions, making it a viable alternative for plant yield and soil quality; however, its environmental impact on GHG emissions requires further attention.

Os registros de produtos com indicação geográfica (IG) são produzidos em regiões que possuem diferenciais, tais como o local e forma de produção, solos, clima e colheita. Este trabalho objetivou delimitar a área geográfica da IG do Planalto Sul Brasileiro (PSB) de produção de mel de melato de bracatinga através da sobreposição de critérios fitogeográficos, climáticos, geológicos, fisiográficos e produtivos. Foi realizada a delimitação geográfica da área, que teve como base o cruzamento de mapas (político, ortobacias, climático, cobertura e uso das terras), modelo digital de terreno e a localização dos produtores de mel. A estruturação da IG do PSB para o mel de melato de bracantinga busca, além do registro de IG, a participação efetiva dos atores na cadeia produtiva, na tomada de decisão, na viabilização de políticas públicas territoriais e na construção de acordos coletivos. A delimitação geográfica permitiu definir a área de produção que permite a obtenção de produto de qualidades específicas. A área da delimitação geográfica da IG mel de melato de bracatinga do PSB para Santa Catarina é de 43.339,5 km2, correspondendo a 45,3% do território; no Paraná a área da IG é de 8.500,6 km2, correspondente a 8,9% do território; e no Rio Grande do Sul é de 7.147,0 km2, cerca de 7,5% do território. Mais estudos devem ser desenvolvidos na região do PSB visando a influência do meio geográfico sobre o produto Mel de Melato da Bracatinga, assim como sobre as propriedades qualitativas desse mel para demonstrar que esse produto tem características únicas.

The multiple environmental dynamics of watersheds make these natural spaces interesting objects of study, and in areas with few scientific investigations, such as the Mestre Campo Stream watershed, the need for these investigations is even greater. The accomplishment of this paper sought to characterize the morphometry of Mestre Campo Stream Watershed, located in Piranga City, Minas Gerais, Brazil, as a first activity to create a management plan for the natural resources available in the area. Therefore, TOPODATA geomorphological data were used in a geographic information system (GIS) to extract the morphometric information – area and respective perimeter, length of axis and of drainage network – from the study area and, then, these variables were used to estimate the following indicators: form factor, circularity and compactness indexes, elongation ratio and drainage density, in order to describe the watershed. The morphometric indexes indicated an elongated behavior for the watershed, characterizing it as a space of low susceptibility to flooding under normal precipitation conditions. In addition, the drainage network showed fourth-order ramifications and a median capacity of drainage. The sub-watersheds that makes the Mestre Campo Stream Watershed were also characterized, the Sub-watershed of Brum Stream presented a rounded shape, while the Alto Mestre Campo Sub-watershed presented elongated characteristics. These results highlight the heterogeneity of Mestre Campo Stream Watershed, which must be considered when elaborating the management plan for the studied watershed, respecting the particularities of that geographic space in order to properly explore its natural resources.