The low natural fertility of Oxisols in the Cerrado region makes some crops in this region very dependent on high rates of synthetic N-fertilizers, which are of growing environmental concern as a major source of N₂O emissions in agriculture. In a field experiment, we quantified direct N₂O emissions and NH₃ volatilization (a source of indirect N₂O emissions) from surface-applied N fertilizer on a no-till maize (Zea maysL.) crop in Cerrado biome. We used four fertilizers at the rate of 120 kg N ha⁻¹ as topdress-N (V4–V6 growth stage), which were regular urea, urea + zeolite, calcium nitrate and ammonium sulfate, and a non-topdressed control. The total N losses as volatilized NH₃ ranged from 2.2% (calcium nitrate) to 4.5% (urea + zeolite). The N loss as volatilized NH₃ from urea was very low (3.2%), with no significant difference between urea + zeolite, ammonium sulfate and calcium nitrate. Significantly, higher cumulated N₂O emissions were observed with ammonium sulfate than with the control. No significant differences among fertilizers were found for emission factor (EF), which was 0.20% on average (0.14–0.26%), indicating that use of IPCC default EF (1.00%) would substantially overestimate N₂O emission. Free drainage and acidity of Oxisols and occurrence of dry spells, known as ‘veranicos’, are characteristics of Cerrado biome that may naturally mitigate N₂O emissions.

Maize production accounts for the largest proportion of synthetic fertilizer-N used in Brazil, with most of it being urea. The use of this fertilizer raises significant agronomic and environmental concerns due to an elevated risk of gaseous N losses, resulting in low fertilizer-N recovery by plants and increasing anthropogenic greenhouse gas (GHG) emissions. In a field trial on a tropical Acrisol, we quantified the N losses caused by the gaseous emissions of NH3 and N2O and the grain yield and recovery of 15N-fertilizer by maize plants treated with urea with added nitrapyrin or N-(n-butyl) thiophosphoric triamide (NBPT). Under conditions favorable for gaseous N loss from fertilizers, nitrapyrin reduced the cumulative N2O emission by 49% over a period of 30days after the subsurface application of side-banded urea (50kgNha−1) during maize sowing. The use of NBPT delayed urea hydrolysis and reduced the NH3 volatilization by 35%, which represents a significant reduction in indirect N2O emission due to subsequent atmospheric deposition. The use of nitrapyrin during sowing and NBPT during the V5 stage of maize growth enhanced urea-15N recovery by 53% and increased maize grain yield by 1.5tha−1 compared to regular urea. Our results indicate that considering the main potential N losses according to timing and placement of fertilizer, the specific use of inhibitors represents an efficient strategy to improve the urea-N recovery and the maize grain yield. The use of nitrification inhibitors can play an effective role in mitigating N2O emissions from typical N fertilization practices in maize-producing areas in Brazil. This study also indicates the need for considering indirect emissions in the overall balance of N2O emissions derived from enhanced-efficiency fertilizers.

The crossbreeding of two or more breeds from the Bos taurus and Bos indicus species is an alternative for obtaining high-quality meat from animals adapted to tropical climates. Quality and sensory attributes of beef, mainly its tenderness and flavour, are very important with regard to the consumer’s point of view. This study aimed to evaluate the physico-chemical and sensory characteristics of crossbred young bulls and heifers, the offspring of Angus or Limousin bulls and 1/2 Angus + 1/2 Nellore or 1/2 Simental + 1/2 Nellore cows that were finished on feedlot or pasture. Meat quality traits (pH, colour, cooking loss, water holding capacity and shear force) and sensory parameters (characteristic beef aroma/flavour intensity, strange aroma/flavour intensity, tenderness and juiciness descriptive attributes, flavour, texture (tenderness) and overall acceptance) were evaluated. The genetic group had an effect on the beef pH, but it was not as relevant as the effect of the combination between the production system and the sex or genetic group, which affected many of the quality and sensory traits.

From the mid twentieth century onwards, the developed and many developing countries experienced rapid changes in their agricultural activity. This was characterized by intensification, supported by mechanization and the use of synthetic fertilizers, chemicals for pest control, together with concentration and specialization, which resulted in enterprises of larger scale focusing on specific products motivated principally by a global market of commodities.

Land-use change (LUC) in Brazil has important implications on global climate change, ecosystem services and biodiversity, and agricultural expansion plays a critical role in this process. Concerns over these issues have led to the need for estimating the magnitude and impacts associated with that, which are increasingly reported in the environmental assessment of products. Currently, there is an extensive debate on which methods are more appropriate for estimating LUC and related emissions and regionalized estimates are lacking for Brazil, which is a world leader in agricultural production (e.g. food, fibres and bioenergy). We developed a method for estimating scenarios of past 20-year LUC and derived CO₂ emission rates associated with 64 crops, pasture and forestry in Brazil as whole and in each of its 27 states, based on time-series statistics and in accordance with most used carbon-footprinting standards. The scenarios adopted provide a range between minimum and maximum rates of CO₂ emissions from LUC according to different possibilities of land-use transitions, which can have large impacts in the results. Specificities of Brazil, like multiple cropping and highly heterogeneous carbon stocks, are also addressed. The highest CO₂emission rates are observed in the Amazon biome states and crops with the highest rates are those that have undergone expansion in this region. Some states and crops showing large agricultural areas have low emissions associated, especially in southern and eastern Brazil. Native carbon stocks and time of agricultural expansion are the most decisive factors to the patterns of emissions. Some implications on LUC estimation methods and standards and on agri-environmental policies are discussed.

The objective of this work was to develop and evaluate a method for estimating corn yield using a minimum number of parameters and limited information about crop management. The proposed method estimates potential and attainable yields based on the technological level of the production systems and on relatively simple agrometeorological models. Corn yield was estimated for the crop seasons from 2000/2001 to 2007/2008, considering several locations and regions in Brazil, and was compared with the actual yield data from official surveys. There was a high correlation between the estimated and observed yield (0.76≤R²<0.92; p<0.01), with model efficiency (E1’) ranging from 0.45 to 0.73; mean relative error (MRE) between -0.9 and 2.4%; and mean absolute error (MAE) of less than 70 kg ha^-1, depending on the technological level adopted. Based on these results, the proposed yield model can be recommended to forecast yields all over the country, contributing to make this process more precise and accurate.

The inoculation of cereal crops with plant growth-promoting bacteria (PGPB) is a potential strategy to improve fertilizer-N acquisition by crops in soils with low capacity to supply N. A study was conducted to assess the impact of three inoculants on grain yield, protein content, and urea-¹⁵ N recovery in maize (Zea mays L.) under Cerrado soil and climate conditions.

The objective of this study was to evaluate the effect of lipid sources on voluntary intake, digestibility, performance, and CH4 emission of Nellore steers grazing Brachiaria brizantha cv. Xaraés forage in the dry season. Forty-five Nellore steers with average weight of 442±34 kg were alloted into one of the five treatments: without additional fat; with palm oil; with linseed oil; with protected fat; and with whole soybeans. The supplements were provided daily and quantities were adjusted to 1% of body weight and diets were formulated in accordance with the Cornell Net Carbohydrate and Protein System. The experimental design was completely randomized with five treatments and two replications. There were no effects on dry matter, organic matter, and neutral detergent fiber intake with the inclusion of lipids in the diet. The neutral detergent fiber showed decreased digestibility in animals receiving linseed oil and palm oil treatments compared with animals receiving the diet without additional fat. The linseed oil treatment reduced CH4 emissions by 38% when expressed in mg/d/kg BW and tended to reduce the emission in g/d/kg BW0.75. Lipid sources did not affect the weight gain of the animals. The intake and performance of grazing Nellore steers supplemented at 1% body weight with lipid sources were not modified. However, fiber digestibility was reduced with palm or linseed oil addition. Linseed oil reduced enteric CH4 emissions. Linseed oil has the potential to reduce enteric CH4 emissions in continuous tropical grazing systems based on B. brizantha grass.

The Rural Sustentável project aims to decrease greenhouse gas emissions, reduce poverty, and promote sustainable rural development in the Brazilian Amazon and Atlantic Forest biomes: by restoring deforested and degraded land, and by facilitating and promoting the uptake of low carbon agricultural technologies. The project offers farmers a) access to information, through demonstration units and field days; b) access to technical assistance, through in-person and online training and capacity-building; c) access to rural credit, through collaborative farmer-technician partnerships, and d) financial incentives, in the form of results based financing to successful farmer-technician teams. The project is still in its implementation stage, but the innovative design and theory of change of this project offer insights into possible mechanisms for promoting forest restoration on private lands in the tropics.