Region-specific emission factors for Brazil increase the estimate of nitrous oxide emissions from nitrogen fertiliser application by 21%

The use of synthetic nitrogen fertilisers is one of the most important land management practices proposed to improve crop and pasture productivity. The use of such fertilisers in excess can lead to greenhouse gas (GHG) emissions, linked to climate change, as well as ammonia (NH3) emissions, linked to eutrophication and soil acidification.. This context is especially important in Brazil, which is responsible for a significant share of the food produced in the world. To assess the impact of the use of nitrogen fertilisers, we conducted a structured review of Brazilian studies on the emission of nitrous oxide (N2O; 11 studies) and ammonia volatilisation (NH3; 13 studies) from nitrogen fertiliser application. The current emission factors (EF) suggested by the IPCC for N2O and NH3 (1 and 11%, respectively) are lower than the mean values we found in our review (1.12 and 19%, respectively). Our results showed that non-urea fertilisers (ammonium nitrate or ammonium sulphate) had a lower emission factor (EF) for N2O (1.07 and 0.60%, respectively) and NH3 (3.17 and 14%, respectively) in comparison with urea. The use of nitrification and urease inhibitors resulted in a reduction of the EFs of N2O (74% lower) and NH3 (43% lower) when compared with the Urea EF. Urea is the most common fertiliser used in Brazil, and the change for non-urea fertilisers or the use of inhibitors could lead to a reduction of 23% in the total N2O inventory. The use of the new region-specific EFs results in an increase of 21% in the final N2O emission inventory

Modelos agrícolas alternativos en Argentina, Nueva Zelanda y Holanda: reflexiones comparativas

La consolidación del modelo productivo convencional a nivel mundial, especialmente ligado a la incorporación de un paquete tecnológico derivado de la denominada Revolución Verde, ha sido objeto de estudio y análisis en los últimos años, dando espacio a numerosos cuestionamientos. Concomitantemente, emergen producciones alternativas. En este contexto, no son frecuentes los estudios que expliquen de forma comparativa el modo en que distintos países abordan estas respuestas alternativas. Este artículo analiza las alternativas al modelo de producción convencional en Argentina, Nueva Zelanda y Holanda considerando el tratamiento público de este tema, a través de normativas, programas y políticas públicas. El carácter metodológico de este estudio es cualitativo, basado en estudios previos de los autores, fuentes de información secundaria y entrevistas en profundidad. Los principales resultados muestran que: los tres casos de estudio, inmersos en disímiles contextos socio-históricos, generan respuestas alternativas diferenciales; las motivaciones para ello son específicas de cada caso, destacándose el interés por consumir alimentos sanos e inocuos, el cuidado del medio ambiente y mejores precios para los agricultores; en los tres casos se corrobora la coexistencia actual de producciones alternativas y convencionales. Las propuestas alternativas tienden a traer visiones más holísticas de los sistemas alimentarios, en las que los miembros de la comunidad son a la vez actores y beneficiarios de las transformaciones que se desarrollan a su alrededor. Al identificar y comparar las diferentes alternativas, es posible reflexionar sobre la forma en que se perciben los problemas y las soluciones en torno a los sistemas agroalimentarios.The consolidation of the conventional production model worldwide, especially linked to the implementation of a technological package derived from the socalled Green Revolution, has been subject of study and analysis in recent years. Concomitantly, alternative productions are emerging. In this context, there are not many studies that explain in a comparative way how different countries approach these alternative responses. This article analyses alternative responses to conventional production model in Argentina, New Zealand and the Netherlands considering the public treatment of this issue, through regulations, programs and public policies. The methodological nature of this study is qualitative, based on previous studies by the authors, sources of secondary information and in-depth interviews. Main results show that: the three case studies, immersed in dissimilar socio-historical contexts, generate differential alternative responses to the conventional production model; the motivations for this are specific to each case, as the interest in consuming healthy and safe food, the care of the environment and better prices for the farmers; in all three cases, the current coexistence of alternative and conventional productions is corroborated. The alternative proposals tend to bring more holistic views of food systems, in which the members of the community are at the same time actors and beneficiaries of the transformations unfolding around them. By identifying and comparing the different emerging alternatives in three countries with such dissimilar characteristics, it is possible to reflect on the way in which problems and solutions around agricultural food systems are perceived, providing useful insights for strategic planning.Fil: Molpeceres, María Celeste. Universidad Nacional de Mar del Plata. Facultad de Humanidades. Centro de Estudios Sociales y Politicos.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Romera, Álvaro. No especifíca;Fil: Jansma, Jan Eelco. No especifíca;Fil: Zulaica, Maria Laura. Universidad Nacional de Mar del Plata. Facultad de Arquitectura, Urbanismo y Diseño. Instituto de Hábitat y Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Mazzetto, Andre. No especifíca;Fil: Shah, Munir. No especifíca

Modelos agrícolas alternativos en Argentina, Nueva Zelanda y Holanda: reflexiones comparativas

La consolidación del modelo productivo convencional a nivel mundial, especialmente ligado a la incorporación de un paquete tecnológico derivado de la denominada Revolución Verde, ha sido objeto de estudio y análisis en los últimos años, dando espacio a numerosos. Concomitantemente, emergen producciones alternativas. En este contexto, no son frecuentes los estudios que expliquen de forma comparativa el modo en que distintos países abordan estas respuestas alternativas. Este artículo analiza las alternativas al modelo de producción convencional en Argentina, Nueva Zelanda y Holanda considerando el tratamiento público de este tema, a través de normativas, programas y políticas públicas. El carácter metodológico de este estudio es cualitativo, basado en estudios previos de los autores, fuentes de información secundaria y entrevistas en profundidad. Los principales resultados muestran que: los tres casos de estudio, inmersos en disímiles contextos sociohistóricos, generan respuestas alternativas diferenciales al modelo productivo convencional; las motivaciones para ello son específicas de cada caso, siendo entre los principales aspectos claves el interés por consumir alimentos sanos e inocuos, el cuidado del medio ambiente y mejores precios para los agricultores; en los tres casos se corrobora la coexistencia actual de producciones alternativas y convencionales. Las propuestas alternativas tienden a traer visiones más holísticas de los sistemas alimentarios, en las que los miembros de la comunidad son a la vez actores y beneficiarios de las transformaciones que se desarrollan a su alrededor. Al identificar y comparar las diferentes alternativas emergentes en tres países con características tan disímiles, es posible reflexionar sobre la forma en que se perciben los problemas y las soluciones en torno a los sistemas agroalimentarios.AcknowledgementsThis work was conducted through the research programme “The New Zealand bioeconomy in the digital age” funded by the AgResearch Strategic Science Investment Fund. We acknowledge the Flevo Campus programme for their support of the research in Almere Oosterwold

Marginal Abatement Cost Curves for Latin American Dairy Production: A Costa Rica case study

This study utilises data collected from Costa Rican dairy farmers to conduct a cradle to farm gate Life Cycle Assessment and the first Marginal Abatement Cost Curve (MACC) for dairy production in Latin America. Ninety dairy farms across five farm typologies were assessed, reflecting Costa Rica's diverse agroclimatic zones and varying degrees of dairy/beef specialisation. The efficacy and cost-effectiveness of specific mitigation measures depend on farm typology, but several promising technologies are identified that increase efficiency whilst substantially reducing emissions across most farms – in particular, measures that improve animal health and increase pasture quality. Pasture measures are synergistic with silvopastoral practises and are highly effective at emission mitigation, although relatively expensive. The replacement of lower quality by-product feeds with high quality concentrate feed is a cost-effective mitigation measure at farm level, but emission reductions could be negated by indirect land use change outside the scope of the MACC analyses. Achieving carbon neutrality at farm level is not likely to be possible for most farms, with the exception of extensive farm typologies. Not all measures are suitable in every context, and additional policy support will be needed to offset financial and technical challenges related to adoption. Results of this first tropical dairy MACC study are constrained by lack of high-resolution data, but they highlight the need for farm-typology-specific mitigation recommendations. Overall, there is a high potential for pasture improvement and silvopastoral measures to mitigate the globally significant contribution of Latin American livestock production to climate change.</p

Mitigation of nitrous oxide emissions in grazing systems through nitrification inhibitors: a meta-analysis

Grasslands are the largest contributor of nitrous oxide (N2O) emissions in the agriculture sector due to livestock excreta and nitrogen fertilizers applied to the soil. Nitrification inhibitors (NIs) added to N input have reduced N2O emissions, but can show a range of efficiencies depending on climate, soil, and management conditions. A meta-analysis study was conducted to investigate the factors that influence the efficiency of NIs added to fertilizer and excreta in reducing N2O emissions, focused on grazing systems. Data from peer-reviewed studies comprising 2164 N2O emission factors (EFs) of N inputs with and without NIs addition were compared. The N2O EFs varied according to N source (0.0001-8.25%). Overall, NIs reduced the N2O EF from N addition by 56.6% (51.1-61.5%), with no difference between NI types (Dicyandiamide-DCD; 3,4-Dimethylpyrazole phosphate-DMPP; and Nitrapyrin) or N source (urine, dung, slurry, and fertilizer). The NIs were more efficient in situations of high N2O emissions compared with low; the reduction was 66.0% when EF > 1.5% of N applied compared with 51.9% when EF 10 kg ha(-1). NIs were less efficient in urine with lower N content (<= 7 g kg(-1)). NI efficiency was negatively correlated with soil bulk density, and positively correlated with soil moisture and temperature. Better understanding and management of NIs can optimize N2O mitigation in grazing systems, e.g., by mapping N2O risk and applying NI at variable rate, contributing to improved livestock sustainability

Comparing how land use change impacts soil microbial catabolic respiration in Southwestern Amazon

Abstract Land use changes strongly impact soil functions, particularly microbial biomass diversity and activity. We hypothesized that the catabolic respiration response of the microbial biomass would differ depending on land use and that these differences would be consistent at the landscape scale. In the present study, we analyzed the catabolic response profile of the soil microbial biomass through substrate-induced respiration in different land uses over a wide geographical range in Mato Grosso and Rondônia state (Southwest Amazon region). We analyzed the differences among native areas, pastures and crop areas and within each land use and examined only native areas (Forest, Dense Cerrado and Cerrado), pastures (Nominal, Degraded and Improved) and crop areas (Perennial, No-Tillage, Conventional Tillage). The metabolic profile of the microbial biomass was accessed using substrate-induced respiration. Pasture soils showed significant responses to amino acids and carboxylic acids, whereas native areas showed higher responses to malonic acid, malic acid and succinic acid. Within each land use category, the catabolic responses showed similar patterns in both large general comparisons (native area, pasture and crop areas) and more specific comparisons (biomes, pastures and crop types). The results showed that the catabolic responses of the microbial biomass are highly correlated with land use, independent of soil type or climate. The substrate induced respiration approach is useful to discriminate microbial communities, even on a large scale

Designing grazing systems that enhance the health of New Zealand high-country grasslands

More sustainable pastoral livestock production systems are required to face the challenge of reconciling agricultural production and environmental impact. Although the need for more holistic approaches, such as systems thinking and design theory, is acknowledged, systemic research applying those theories to create healthier systems remains underexplored. A multiple steps holistic approach involving modelling, geographic information systems, and decision-making analysis was used to design, assess, and contrast alternative scenarios that represent distinct grazing management to the current grazing management of a high-country station in New Zealand used as a case study to enhance grassland health. Three alternative scenarios were created, and five main parameters used to assess grassland health were obtained from the evaluation of the designed scenarios. From all the parameters, soil erosion control and increased production were ranked as the most and least important, respectively, to be considered in the design process. A multi-criteria evaluation defined that the best-compromise scenario to enhance grassland health is the scenario with lower soil erosion, as a result of applying adaptive and flexible management at the paddock level, the lower total emission of greenhouse gases (only sheep herd grazing), and greater profitability (due to production costs reduction, as cattle were removed from the station), compared to the ‘status quo’. Our design methodology produced a variety of alternatives that enhanced the health of grasslands in different parameters while still maintaining or increasing profitability. The use of multi-criteria evaluation facilitated the decision of the most contextualised and best-compromise scenario for New Zealand high country grasslands

Comparing the environmental efficiency of milk and beef production through life cycle assessment of interconnected cattle systems

Dairy production has a substantial environmental impact. Currently, most studies analysing the environmental burdens of milk production employ attributional Life Cycle Assessment (LCA), for cradle to farm-gate analysis of dairy systems. This approach calculates environmental footprints per kg fat and protein corrected milk (FPCM). However, milk and beef production are inherently interconnected, and a narrow focus on milk production neglects wider synergies and trade-offs across cattle systems, outside dairy farm boundaries. For the first time, we applied an expanded boundary LCA of coupled dairy and beef production in Latin America, considering 1 kg FPCM plus 100 g of beef as functional unit (FU) to reflect the current global beef:milk demand ratio and taking into account the complexities of Costa Rican cattle production systems. Boundaries encompassed fattening of surplus dairy calves and incurred or avoided suckler-beef production needed to deliver the FU. A database of 552 Costa Rican farms (203 beef and 349 dairy farms) was analysed using a farm LCA model to generate results across five impact categories (Global Warming Potential – GWP; Eutrophication; Acidification; Abiotic Resource Depletion; and Land Occupation - LO). Normalised scores indicated that cattle systems contribute most strongly to per capita GWP and LO burdens. Cradle to farm-gate attributional LCA showed that milk produced by dual-purpose farms had the largest GWP and LO footprints, whilst specialist farms had the smallest footprints, per kg FPCM. The expanded boundary LCA showed that dual-purpose farms generated smaller GWP footprints per kg FPCM plus 100 g beef than specialised dairy farms, though still required more land. Key factors were the herd structure, influencing the amount of beef produced, and milk yields per animal, reflecting the level of dairy specialisation. This new evidence on the environmental efficiency of cattle production systems emphasises the imperative to consider both milk and beef production as well as multiple environmental pressures across interconnected milk and beef production systems when designing sustainable intensification mitigation strategies

Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement

Objective: To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres. Background: It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic. Materials and methods: Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to ANOVA and Tukey's HSD test. Results: A significant statistical difference was observed with regard to the polymerisation method and the GFR (p < 0.05). Without the GFR, the acrylic resin VC presented the highest hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest. Conclusions: The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT.292E155E16