The main discoveries and advances in the development of industrial processes for the most commercially used phosphate fertilizers in the world (single superphosphate, triple superphosphate, monoammonium phosphate, and diammonium phosphate) occurred from 1830 to 1970, followed by improvements and investments to expand worldwide production capacity. A main opportunity now is aggregating new technologies to conventional phosphate fertilizers so they may become even more efficient in supplying P to plants, which involves research related to the technologies for reduction in soil P losses. Thus, some innovations and technologies have begun to be developed and marketed and continue in continual refinement and adoption in agriculture worldwide to reduce conversion of soluble P applied through conventional phosphate fertilizers into unavailable forms in the soil. This is the case of enhanced efficiency fertilizers, which includes groups of phosphate fertilizers with fixation inhibitors and the chemically modified, controlled-release, blends, multifunctional, and synergistic phosphate fertilizers. The technologies presented in detail in this paper were developed to improve the agronomic efficiency of phosphate fertilization in comparison with conventional fertilizers, with costs varying according to raw materials, production technologies, and distance from the consumer market. This synthesis expands knowledge regarding technologies in use, stimulating the development and application of technologies that increase nutrient efficiency, based on results obtained through suitable methods and equipment along with laboratory, greenhouse, and field results. Increased fertilization efficiency should always be linked with greater economic profitability and the lowest environmental impact, following the principles of sustainability and circular economy. The great challenge for innovation is transforming the knowledge generated regarding fertilizers present in patents and scientific publications into technologies appropriate for the fertilizer market and for adoption in agriculture.
The aim of this study was to quantify NH3-N losses from conventional, stabilized, slow-release, and controlled-release N fertilizers in a coffee field. The N fertilizers analyzed were prilled urea, prilled urea dissolved in water, ammonium sulfate (AS), ammonium nitrate (AN), urea + Cu + B, urea + adhesive + CaCO3, and urea + NBPT (all with three split applications), as well as blended N fertilizer, urea + elastic resin, urea-formaldehyde, and urea + polyurethane (all applied only once). NH3-N losses (mean of two crop seasons) were statistically higher for urea + adhesive + CaCO3 (27.9% of applied N) in comparison with the other treatments. Loss from prilled urea (23.7%) was less than from urea + adhesive + CaCO3. Losses from urea + NBPT (14.5%) and urea + Cu + B (13.5%) were similar and lower than those from prilled urea. Urea dissolved in water (4.2%) had even lower losses than those treatments, and the lowest losses were observed for AS (0.6%) and AN (0.5%). For the single application fertilizers, higher losses occurred for urea + elastic resin (5.8%), blended N fertilizer (5.5%), and urea + polyurethane (5.2%); and urea-formaldehyde had a lower loss (0.5%). Except for urea + adhesive + CaCO3, all N-fertilizer technologies reduced NH3-N losses compared to prilled urea.
The assessment of energy efficiency (EE) and greenhouse gas (GHG) emissions can highlight the sustainability of agro-systems and decision-making regarding reduction of production costs and environmental pollution. In this context, the objective of this work was to evaluate the EE and GHG emissions (CO2, CH4 e N2O) of a soybean crop under organic cultivation in different regions of Brazil in the agricultural year 2014-2015. For this, 19 soybean areas were evaluated. The inputs and outputs of the agricultural operations and / or inputs used were calculated by multiplying the quantity used by their calorific value or energy coefficient at each stage of production. The energy efficiency was obtained by the ratio between the amount of total output energy and the total energy consumption during the production process. In order to estimate GHG emissions, the principles of the life cycle assessment methodology and recommendations of the Intergovernmental Panel on Climate Change (IPCC) were applied. For each 1.0 MJ of energy consumed in the organic production of soybeans, an average of 7.9 MJ of renewable energy was produced in the form of grains of this crop. The main energy costs of growing these organic crops were with seeds, fuel and with tractors, machines and agricultural implements (TMI). For each 1 kg of organic grain produced from soybeans, 0.19 kg of CO2eq are emitted during their production and delivery cycles in the warehouse. The main sources of CO2eq emission to the atmosphere were the seeds, fuels and organic fertilizers.
The soybean crop in Brazil has been growing in area and productivity in recent years and the analysis of its energy efficiency is very important to guarantee the sustainability of the production system. Assessment of energy efficiency (EE) enables the evaluation of the sustainability of agrosystems, as well as decision-making regarding the reduction in production costs and negative environmental impacts. In this context, the objective of this study was to assess energy efficiency of soybean in different regions of Brazil. For this purpose, 29 areas of soybean across the major producing states were assessed. Energy inputs and outputs of agricultural operations and/or agricultural inputs were calculated by multiplying the amount used by their calorific value or energy coefficient at each stage of production. Energy efficiency was calculated as the ratio between the total output energy and the total input energy during the production process. For every MJ of energy consumed in the production of soybean crop, 6.1; 6.7; 7.1 and 7.2 MJ of energy were produced in the form of grain, respectively in the areas assessed in the Midwest, northeast, southeast and south regions of Brazil. Generally, the main energy expenditure on soybean cultivation in different regions of Brazil was with fertilizers, seeds and herbicides. The adverse weather conditions of the year / harvest evaluated in the south-central region of Brazil resulted in low soybean yields and consequently resulted in lower energy efficiency in these regions. The evaluation of energy efficiency in soybean crops to be representative must be carried out in different regions and edaphoclimatic conditions.
Boron (B) is readily leached from the soil, depending on the soil texture, soil organic matter (OM) content, and the fertilizer source used. This can restrict B uptake by plants. Therefore, we investigated the most adequate B source for soybeans grown in soils with contrasting textures and OM contents. The plants were cultivated for 55 days in columns filled with clayey or sandy Oxisols with low or high OM contents. The clay contents (%) in the soils were as follows: clayey soil with low OM = 64; clayey soil with high OM = 67; sandy soil with low OM = 4; and sandy soil with high OM = 15. The B sources tested comprised the control (no B supply), ulexite, zinc borate, boric acid, and B-monoethanolamine (B-MEA), with the equivalent of 6 kg B ha–1 applied. Boron leaching from ulexite was lower than other B fertilizers in the sandy soil with high OM content. Boron leaching was higher in sandy than in clayey soils. Boron accumulation in shoots was lower when boric acid was applied to the sandy soil with low OM content than the other B fertilizers. In this same soil, the agronomic efficiency and recovery of B applied by plants supplied with ulexite and zinc borate were higher compared to boric acid and B-MEA. In conclusion, the use of ulexite and zinc borate is more appropriate for soybean fertilization in sandy soils with low OM content, while B-MEA is more suitable for sandy soils with high OM content.
Assessment of energy efficiency (EE) enables the evaluation of the sustainability of agrosystems, as well as decision-making regarding reduction in production costs and environmental pollution and even to increase production in a sustainable way. In this context, the objective of this study was to assess energy efficiency in maize in different regions of Brazil. For this purpose, 32 areas of maize crop distributed across the major producing states and regions were assessed. Energy inputs and outputs of agricultural operations and/or agricultural inputs were calculated by multiplying the amount used by their calorific value or energy coefficient at each stage of production. Energy efficiency was calculated as the ratio between the total output energy and the total input energy during the production process. For every megajoule (MJ) of energy consumed in the production of second-crop maize and first-crop maize seasons, 9.9 and 8.7 MJ respectively of renewable energy were produced in the form of grain. In both maize cropping seasons, most of the energy use was attributed to fertilizers, herbicides and fuel. To be representative the evaluation of energy efficiency of the maize crop should be performed in different Brazilian cultivation regions, as it will represent different edaphoclimatic and management conditions spread over the national territory within an agricultural year.