The burgeoning demand for rice in Latin America and Caribbean (LAC) exceeds supply, resulting in a rice deficit. To overcome this challenge, rice production should be increased, albeit sustainably. However, since rice production is associated with increases in the atmospheric concentration of two greenhouse gases (GHGs), namely methane (CH₄) and nitrous oxide (N₂O), the challenge is on ensuring that production increases are not associated with an increase in GHG emissions and thus do not cause an increase in GHG emission intensities. Based on current understanding of drivers of CH₄ and N₂O production, we provide here insights on the potential climate change mitigation benefits of management and technological options (i.e., seeding, tillage, irrigation, residue management) pursued in the LAC region. Studies conducted in the LAC region show intermittent irrigation or alternate wetting and drying of rice fields to reduce CH₄ emissions by 25–70% without increasing N₂O emissions. Results on yield changes associated with intermittent irrigation remain inconclusive. Compared to conventional tillage, no-tillage and anticipated tillage (i.e., fall tillage) cause a 21% and 25% reduction in CH₄ emissions, respectively. From existing literature, it was unambiguous that the mitigation potential of most management strategies pursued in the LAC region need to be quantified while acknowledging country-specific conditions. While breeding high yielding and low emitting rice varieties may represent the most promising and possibly sustainable approach for achieving GHG emission reductions without demanding major changes in on-farm management practices, this is rather idealistic. We contend that a more realistic approach for realizing low GHG emitting rice production systems is to focus on increasing rice yields, for obvious food security reasons, which, while not reducing absolute emissions, should translate to a reduction in GHG emission intensities. Moreover, there is need to explore creative ways of incentivizing the adoption of promising combinations of management and technological options.

No-tillage (NT) has been one of the main advances related to soil management in Brazilian agriculture in the last 30 years. However, its full adoption in lowland areas that are traditionally cultivated with flooded rice is still incipient (<5 %). The main reasons are associated with the soil hydromorphic condition and the management of highly recalcitrant residual crop biomass, demanding soil disturbance even occasionally. This review presents a historical survey about the soil management systems utilized in lowland areas [...] No-tillage (NT) has been one of the main advances related to soil management in Brazilian agriculture in the last 30 years. However, its full adoption in lowland areas that are traditionally cultivated with flooded rice is still incipient (<5 %). The main reasons are associated with the soil hydromorphic condition and the management of highly recalcitrant residual crop biomass, demanding soil disturbance even occasionally. This review presents a historical survey about the soil management systems utilized in lowland areas

O objetivo deste trabalho foi avaliar o desempenho produtivo de mudas nacionais e importadas de morangueiro das cultivares Aromas e Camarosa, nas condições climáticas de Pelotas. O experimento foi realizado utilizando sistema de produção sob túnel, irrigação por gotejamento e adubação fornecida via água de irrigação. O transplantio das mudas foi realizado em junho de 2005, num espaçamento de 35 cm entre linhas e entre plantas. Utilizaram-se mudas de duas cultivares (Aromas e Camarosa) e de três procedências (Chile, Serra Gaúcha e região de Pelotas). Os tratamentos foram dispostos em delineamento de blocos ao acaso, em esquema fatorial com quatro repetições. As unidades experimentais foram constituídas por 20 plantas. Semanalmente, de agosto a dezembro, foram analisadas as variáveis número e massa fresca de frutos. A cv. Camarosa (569,6 g planta-1) foi mais produtiva do que a 'Aromas' (510,4 g planta-1). Independentemente da cultivar, as mudas importadas do Chile proporcionaram maior produção de frutos comerciais (724,5 g planta-1) e frutos de maior massa (15,5 g) do que as mudas produzidas na região de Pelotas (493,3 planta-1 e 12,6 g fruto-1) e na Serra Gaúcha (402,3 g planta-1 e 11,7 g fruto-1).

O objetivo deste trabalho foi determinar a influência da tensão de água e de atributos físicos e químicos do solo sobre a produtividade do arroz irrigado por aspersão, em terras baixas no Rio Grande do Sul. Na safra 2011/2012, foram avaliados os efeitos das tensões de água no solo de 20 e 40 kPa, durante todo o ciclo da cultura, bem como as de 40 e 20 kPa nas fases vegetativa e reprodutiva, respectivamente. Na safra 2012/2013, foram avaliadas as tensões de 10, 20 e 40 kPa, durante todo o ciclo da cultura, e as de 40 e 10 kPa nas fases vegetativa e reprodutiva, respectivamente. Em ambas as safras, utilizou-se a cultivar de arroz irrigado BRS Pampa. O gasto com água na irrigação por aspersão representou 48% do gasto com a irrigação por inundação. A produtividade do arroz correlacionou-se positivamente com a microporosidade e com os teores de fósforo e potássio disponíveis no solo; e negativamente com a macroporosidade e a saturação por alumínio. A avaliação conjunta da tensão de água e de atributos físicos e químicos do solo permite avaliar com mais propriedade a variabilidade na produtividade de arroz irrigado por aspersão em terras baixas no Rio Grande do Sul. A irrigação por aspersão possibilita melhor uso da água proveniente da precipitação pluvial, com efeitos positivos sobre a economia de água.

Paddy fields are significant anthropogenic sources of methane (CH₄) emissions. In southern Brazil, rice is grown in lowland flooded areas once a year, followed by a long fallow period. This study aimed to measure CH₄ fluxes in a rice paddy field in southern Brazil during the rice-growing season of 2015/2016 and the following fallow period. The fluxes were estimated using the eddy covariance (EC) technique and soil chamber (SC). Diurnal and seasonal variations of CH₄ fluxes and potential meteorological drivers were analyzed. The CH₄ fluxes showed distinct diurnal variations in each analyzed subperiod (vegetative, reproductive, pre-harvest, no rice, and land preparation), characterized by a single-peak diurnal pattern. The variables that most influenced methane emissions were air and surface temperatures. In the growing season, the rice vegetative stage was responsible for most of the measured emissions. The accumulated annual emission estimated was 44.88 g CH₄ m⁻² y⁻¹, being 64% (28.50 g CH₄ m⁻²) due to the rice-growing season and 36% (16.38 g CH₄ m⁻²) due to the fallow period. These results show the importance of including fallow periods in strategies to mitigate methane emissions in flood irrigated rice-growing areas.