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We conducted two experiments. The first aimed to obtain and characterize microparticles of slow-release urea (SRU) using calcium alginate as the encapsulating agent. The second experiment evaluated their inclusion in sheep diets. In the first experiment, four treatments from a completely randomized design were employed to develop an SRU through the ionic gelification technique testing two drying methods (oven and lyophilizer) and addition or no of sulfur (S): SRU oven-dried with sulfur (MUSO) and without sulfur (MUO), SRU freeze-dried/lyophilized with (MUSL), and without sulfur (MUL). MUO exhibited better yield and encapsulation efficiency among these formulations than the others. Therefore, the second experiment was conducted to compare free urea (U) as control and three proportions (1%, 1.5%, and 2% of total dry matter) of MUO in the diet of sheep. Twenty-four non-castrated male Santa Ines lambs, with an average body weight of 22 ± 3.0 kg, were used and distributed in a completely randomized design with four treatments and six replications. The inclusion of 1% alginate-encapsulated urea (MUO1%) resulted in higher dry matter (DM) intake than free urea (p ≤ 0.05). MUO2% inclusion promoted higher NDF digestibility than U and MUO1%. MUO1% showed higher DM than MUO2% and higher NFC digestibility than U and MUO2% (p ≤ 0.05). Sheep fed MUO1.5% and MUO2% exhibited similar nutrient intake and digestibility. Sheep receiving MUO1% had higher N-intake, N-urinary, N-excretion total, N-digested, and N-retained compared to U. Sheep fed MUO1% showed greater N-retained (as % ingested and digested), microbial protein production, and efficiency when compared to other treatments (p ≤ 0.05). MUO2% addition (SRU) promoted the lowest microbial protein production and efficiency in sheep. MUO dietary inclusion increased feeding time and reduced idleness time compared to U, regardless of the MUO level (p ≤ 0.05). Adding MUO1% improved the intake efficiency of DM and NDF and resulted in more feed boli than the other MUO levels (p ≤ 0.05). Sheep receiving U had (4 h after fending) higher NH3-N, pH, and blood urea nitrogen (BUN) and lower TGL serum compared to sheep fed MUO (p ≤ 0.05), without significant difference among MUO levels (p > 0.05), except NH3-N was higher in MUO1.5% and MUO2% compared to MUO1.0%. The external ionic gelation technique proved suitable for urea microencapsulation in calcium alginate (3%), demonstrating high quality, efficiency, and yield. MUO represents a promising slow-release urea for ruminants and is recommended for sheep diets at an inclusion level of 1.0%. This inclusion level improves intake efficiency and nutrient digestibility, increases rumen nitrogen retention, and reduces BUN without compromising sheep health.
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Digestão , Ureia , Animais , Masculino , Alginatos/metabolismo , Alginatos/farmacologia , Ração Animal/análise , Dieta/veterinária , Nitrogênio/metabolismo , Rúmen/metabolismo , Ovinos , Enxofre , Ureia/metabolismoRESUMO
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.
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There is increasing pressure to identify natural feed additives to mitigate methane emissions from livestock systems. Our objective was to investigate the effects of essential oils (EO) extracts star anise (Illicium verum), citronella (Cymbopogon winterianus), clove bud (Eugenia caryophyllus), staigeriana eucalyptus (Eucalyptus staigeriana), globulus eucalyptus (Eucalyptus globulus), ginger (Zingiber officinale), ho wood (Cinnamomum camphora), melaleuca (Melaleuca alternifolia), oregano (Origanum vulgare) and white thyme (Thymus vulgaris) on in vitro methane emissions from four rumen-cannulated Nellore cattle grazing a tropical grass pasture as inoculum donors. The semi-automated gas production technique was used to assess total gas production, dry matter degradability, partitioning factor, ammoniacal nitrogen, short-chain fatty acids and methane production. All essential oils were tested in four doses (0, 50, 250 and 500 mg/L) in a randomized block design, arranged with four blocks, 10 treatments, four doses and two replicates. Within our study, oregano and white Thyme EO reduced net methane production at 250 mg/L, without affecting substrate degradation. Essential oils from oregano and white thyme have the potential to modify ruminal fermentation and suppress rumen methanogenesis without negative effects on feed digestibility, indicating promise as alternatives to ionophores for methane reduction in beef cattle.
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Óleos Voláteis , Origanum , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Digestão , Fermentação , Metano , Óleos Voláteis/metabolismo , Óleos Voláteis/farmacologia , Poaceae/metabolismo , Rúmen/metabolismoRESUMO
The design of new materials with two or more functional groups must be strongly considered to achieve multifunctional coatings with outstanding properties such as active-passive protection against corrosion, low-friction, antifouling, and sensing, among others. In this sense, nanocomposites based on solvent-free epoxy resin/bifunctionalized reduced graphene oxide layers with NH2 and NH3+ groups (ER/BFRGO) with super-anticorrosive properties are for the first time reported here. The amine groups (-NH2) act as cross-linker agents, which react with epoxy terminal groups from resin, thus closing the gap between the BFRGO layers and the polymeric matrix. Meanwhile, the ammonium ions (-NH3+) are effective trapping agents of negatively charged atoms or molecules (e.g., Cl-). This novel combination enables us to obtain nanocomposite coatings with passive-active protection against corrosion. ER/BFRGO deposited onto A36 mild steel exhibited a remarkably enhanced barrier against corrosion into a saline medium (1 M NaCl; 58.4 g/L), wherein the corrosion current density (icorr) was diminished 6 orders of magnitude (icorr = 5.12 × 10-12 A/cm2), with respect to A36 mild steel coated only with ER (icorr = 2.34 × 10-6 A/cm2). Also, the highest polarization resistance Rp = 6.04 × 107 Ω/cm2 was obtained, which represents the lowest corrosion rate and corresponds to 3 orders of magnitude higher than A36 mild steel coated with ER (Rp = 1.43 × 104 Ω/cm2). The strategy of bifunctionalization proposed herein to obtain bifunctionalized reduced GO with NH2 and NH3+ groups has not been disclosed in the literature before; in consequence, this work opens a new pathway toward the design of smart materials based on multifunctional nanomaterials.
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Agriculture is the largest source of ammonia (NH3) emissions. As NH3 is an indirect greenhouse gas, NH3 measurements are crucial to improving greenhouse gas emission inventory estimates. Moreover, NH3 emissions have wider implications for environmental and human health. Only a few studies have measured NH3 emissions from pastures in the tropics and subtropics and none has compared emissions to inventory estimates. The objectives of this study were to (1) measure NH3 emissions from dairy pastures in tropical and subtropical regions; (2) calculate NH3 emissions factors (EF) for each campaign; and (3) compare measured EF with those based on the 2006 Intergovernmental Panel on Climate Change (IPCC) Tier 1, 2019 Refinement to the 2006 IPCC Tier 1, and the European Monitoring and Evaluation Programme/European Environmental Agency (EMPE/EEA) Tier 2 inventory estimates. Pasture NH3 emissions were measured on 3 dairy farms in Costa Rica. On each dairy, NH3 emissions were measured twice during the wet season and once during the dry season using a micrometeorological integrated horizontal-flux mass-balance method. Emissions were measured from excreta (dung and urine) deposited by grazing cattle and the subsequent application of organic (slurry) or synthetic fertilizer (ammonium nitrate or urea). Measured EF for all campaigns [from grazing cattle excreta and any subsequent slurry or fertilizer application; 4.9 ± 0.9% of applied nitrogen (mean ± SE)] were similar to those of the EMEP/EEA Tier 2 approach (6.1 ± 0.9%; mean ± SE) and 4 times lower than 2006 IPCC and 2019 Refinement to 2006 IPCC Tier 1 default estimates (17.7 ± 1.4 and 18.2 ± 0.9%, respectively; mean ± SE). Measured EF for excreta deposited on pasture and excreta both deposited on pasture and slurry application [3.9 ± 2.1 and 4.2 ± 2.1% (mean ± 95% CI), respectively] were 5 times lower than default EF assumed by 2006 IPCC and 2019 Refinement to 2006 IPCC methodology (both 20 and 21%, respectively), whereas EMEP/EAA estimates were similar [6.0 and 4.6 ± 0.3% (mean ± 95% CI), respectively]. This suggests an overestimation of EF from excreta deposited on pasture and slurry applications in tropical and subtropical regions by IPCC methodologies. Furthermore, rainfall, which is not included as a parameter in the current EMEP/EEA Tier 2 methodology, appeared to reduce NH3 emissions, suggesting that accounting for this in the inventory methodologies could improve inventory estimates.
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Amônia/análise , Bovinos/metabolismo , Indústria de Laticínios , Monitoramento Ambiental , Gases de Efeito Estufa/análise , Agricultura , Animais , Mudança Climática , Costa Rica , Fertilizantes/análise , Nitrogênio/análise , Estações do Ano , Clima TropicalRESUMO
Nitrous oxide (N2O) emissions from pasture-based livestock systems represent 34% of Brazil's agricultural greenhouse gas emissions. The forage species Brachiaria humidicola is known for its biological nitrification inhibition (BNI) capacity and N2O emissions reduction ability from urine patches under tropical conditions. However, there is little information about the effect of BNI on N2O emission and ammonia (NH3) volatilisation in the subtropics. This study aimed to: (i) evaluate the potential of Brachiaria humidicola, compared with Panicum maximum (Jacq. cv. Áries; guinea grass), a broadly used grass (with no BNI capacity), to reduce N2O emissions under subtropical conditions; (ii) determine the efficacy of nitrification inhibitor dicyandiamide (DCD) to decrease N2O emissions; and (iii) determine the effect of brachiaria and DCD application on NH3 volatilisation. A field experiment was carried out using a Cambisol, where cattle urine ± DCD was applied to brachiaria and guinea grass. Over the 67-day measurement period, cumulative N2O emissions were 20% lower from urine patches in the brachiaria treatment (1138 mg N m-2, Emission factor = 1.06%) compared to guinea grass (1436 mg N m-2, Emission factor = 1.33%) (P < .10). A greenhouse experiment, using pots with the same treatments as in the field experiment, suggested that this could have been due to lower soil nitrate levels under brachiaria forage compared to guinea grass, indicating that BNI could be a possible mechanism for lower N2O emissions from brachiaria. The DCD application was effective in both forage species, decreasing N2O emissions by 40-50% (P < .10) compared with the urine only treatment. Approximately 25% of the urine applied N was lost via NH3 volatilisation, however the NH3 loss was not affected by forage species or DCD application (P > .10). Overall, the results demonstrated that brachiaria and DCD use are strategies that can reduce N2O emissions from urine patches.
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Brachiaria , Agricultura , Poluentes Atmosféricos , Amônia , Animais , Brasil , Bovinos , Fertilizantes , Guanidinas , Óxido Nitroso , SoloRESUMO
The purpose of this study was to find an alternative application for chrysotile asbestos, given that there is a complete structure of extraction and production of this class of serpentine minerals, but its use is banned for many applications. The idea was to obtain a compound that could immobilize phosphate by triggering a reaction between the magnesium oxide and hydroxide contained in the mineral, without causing phosphate leaching. To this end, chrysotile (Mg3SiO5(OH)4) was treated with phosphoric acid (H3PO4) in a molar ratio of 1:3 in an aqueous medium at 85 °C until the solvent evaporated, resulting in two different solid compounds, which were prepared in a similar manner. The first compound (cri/H3PO4 1:3)1, was obtained by rinsing and then heat-treating it at 150 °C for 6 h, while the second one, (cri/H3PO4 1:3)2, was rinsed after the heat treatment. Compound (cri/H3PO4 1:3)1 underwent partial leaching, while compound (cri/H3PO4 1:3)2 showed a mass increase of 48%, with the formation of crystalline magnesium pyrophosphate mixed with amorphous SiO2. The latter compound adsorbed N-NH3 at pH 10, following the pseudo-first-order model (activation energy = 8329 ± 1696 J mol-1). Equilibrium experiments, which were performed following Hill's sigmoidal type S2 isotherm model, indicated that the adsorption phenomenon was governed by two processes, i.e., complexation up to the inflection point (KH between 10.0 mg L-1 at 40 °C and 13.6 mg L-1 at 25 °C) followed by adsorption. The qmax varied from 18.0 to 19.6 mgN g-1 and the adsorbent was reusable, maintaining its initial adsorbent capacity during its first reuse. This material, which was tested on real effluents, presented a N-NH3 removal rate similar to that shown by the test solutions. The treatment of chrysotile with H3PO4 conducts it to a composite that adsorbs ammoniacal nitrogen at pH 10 and it is reusable maintaining the adsorption capacity.
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The objective of this study was to determine whether a combination of crude glycerin (CG) and soyabean oil (SO) could be used to partially replace maize in the diet of Nellore steers while maintaining optimum feed utilisation. Eight castrated Nellore steers fitted with ruminal and duodenal cannulas were used in a double 4×4 Latin square design balanced for residual effects, in a factorial arrangement (A×B), when factor A corresponded to the provision of SO, and factor B to the provision of CG. Steers feed SO and CG showed similar DM intake, DM, organic matter and neutral-detergent fibre digestibility to that of steers fed diets without oil and without glycerine (P>0·05). Both diets with CG additions reduced the acetate:propionate ratio and increased the proportion of iso-butyrate, butyrate, iso-valerate and valerate (P<0·05). Steers fed diets containing SO had less total N excretion (P<0·001) and showed greater retained N expressed as % N intake (P=0·022). SO and CG diet generated a greater ruminal abundance of Prevotella, Succinivibrio, Ruminococcus, Syntrophococcus and Succiniclasticum. Archaea abundance (P=0·002) and total ciliate protozoa were less in steers fed diets containing SO (P=0·011). CG associated with lipids could be an energy source, which is a useful strategy for the partial replacement of maize in cattle diets, could result in reduced total N excretion and ruminal methanogens without affecting intake and digestibility.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Bovinos/fisiologia , Glicerol/administração & dosagem , Rúmen/microbiologia , Óleo de Soja/administração & dosagem , Zea mays , Ração Animal/análise , Animais , Bovinos/microbiologia , Clostridiales/isolamento & purificação , Clostridiales/metabolismo , Dieta/veterinária , Digestão , Fermentação , Masculino , Prevotella/isolamento & purificação , Prevotella/metabolismo , Rúmen/metabolismo , Ruminococcus/isolamento & purificação , Ruminococcus/metabolismo , Succinivibrionaceae/isolamento & purificação , Succinivibrionaceae/metabolismo , Veillonellaceae/isolamento & purificação , Veillonellaceae/metabolismoRESUMO
ABSTRACT The market of stabilized, slow and controlled release nitrogen (N) fertilizers represents 1% of the world fertilizer consumption. On the other hand, the increase in availability, innovation and application of these technologies could lead to the improvement of N use efficiency in agroecossystems and to the reduction of environmental impacts. The objective of this study was to quantify agronomic efficiency relative index, ammonia volatilization, and CO2 emissions from conventional, stabilized and controlled release N fertilizers in corn summer crop. The experiment was carried out in a corn crop area located in Lavras, state of Minas Gerais, Brazil, without irrigation. All treatments were applied in topdressing at rate of 150 kg ha-1 N. N-NH3 losses from N fertilizers were: Granular urea (39% of the applied N ) = prilled urea (38%) > urea coated with 16% S0 (32%) = blend of urea + 7.9% S0 + polymers + conventional urea (32%) > prilled urea incorporated at 0.02 m depth (24%) > urea + 530 mg kg-1 of NBPT (8%) = Hydrolyzed leather (9%) > urea + thermoplastic resin (3%) = ammonium sulfate (1%) = ammonium nitrate (0.7%). Thermoplastic resin coated urea, ammonium nitrate and ammonium sulfate presented low values of cumulative CO2 emissions in corn crop. On the other hand, hydrolyzed leather promoted greater C-CO2 emission, when compared with other nitrogen fertilizers.
RESUMO O consumo de fertilizantes nitrogenados estabilizados, de liberação lenta e controlada representa 1% do total de fertilizantes utilizados no mundo. Por outro lado, um aumento na disponibilidade, inovação e utilização dessas tecnologias pode levar a maior eficiência no uso do nitrogênio (N) na agricultura com menor impacto ambiental. O objetivo deste trabalho foi quantificar as perdas de amônia (N-NH3) por volatilização e as emissões de CO2 de fertilizantes nitrogenados convencionais, estabilizados e de liberação controlada na cultura do milho. O experimento foi realizado em condições de campo no município de Lavras (MG) no ano agrícola 2013/2014, sem irrigação. Os tratamentos foram compostos por fertilizantes nitrogenados aplicadas em cobertura na dose de 150 kg ha-1 de N. A perda acumulada de N-NH3 dos fertilizantes nitrogenados convencionais, estabilizados de liberação controlada em ordem decrescente foi: Ureia granulada (39% do N aplicado) = ureia perolada (38%) > ureia + 16% de S0 (32%) = mistura física de grânulos (blend) de ureia revestida com S0 e polímeros e ureia convencional (32%) > ureia perolada incorporada (24%) > ureia + 530 mg kg-1 de NBPT (8%) = hidrolisado de couro bovino (9%) > ureia + resina termoplástica (3%) = sulfato de amônio (1%) = nitrato de amônio (0,7%). O sulfato e nitrato de amônio e a ureia + resina termoplástica promovem a menor emissão de dióxido de carbono (C-CO2) em área de cultivo de milho. Enquanto que, o hidrolisado de couro promoveu a maior emissão total de C-CO2 para à atmosfera.
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This study aimed to evaluate the production of methane, carbon dioxide, and volatile fatty acids and changes in ruminal pH in vitro with oilseed press cakes inclusion, such as, cottonseed, sunflower, castor bean, moringa and jatropha at four different levels (0, 30, 50 and 70%) in replacement to the sugarcane in ruminant feeding using semi-automated in vitro technique. The byproduct that produced less CO2 was cottonseed cake (p = 0.0059). The cakes that produced the least amount of CH4 were moringa at 70% (p 0.05) and cottonseed at 70% levels (p 0.0001). The cakes that had the highest increases in VFAs were cottonseed and castor (p 0.0001). Additionally, greater pH was moringa at 70% and cottonseed at 50% levels (p 0.0001). The greater acetate concentration was 70% cottonseed cake, propionate concentration with 30% cottonseed and butyrate concentration with 50% moringa in sugarcane replace. At the 70% level, the moringa cake displayed the highest decreases in methane production and reduction in energy loss. At the 50% substitution level, the cottonseed cake is the most suitable replacement for sugarcane in order to reduce the production of greenhouse gases.
Objetivou-se avaliar a produção de metano, dióxido de carbono, ácidos graxos voláteis e mudanças no pH ruminal in vitro com tortas de oleaginosas: algodão, girassol, mamona, moringa e pinhão manso incluídas em quatro níveis diferentes (0, 30, 50 e 70%) em substituição à cana-de-açúcar na dieta de ruminantes, utilizando-se a técnica semiautomática in vitro. O subproduto que produziu menos CO2 foi o algodão (p = 0,0059). As tortas de oleaginosas que produziram menos CH4 foram moringa (p 0,05) e algodão (p 0,0001) a 70% de inclusão. As tortas que aumentaram a produção de AGVs foram algodão e mamona (p 0,0001). Além disso, o pH aumentou nos níveis de inclusão a 70% de moringa e 50% de algodão (p 0,0001). A maior concentração de acetato ocorreu na torta de algodão a 70%, já o propionato na torta de algodão à 30% e a maior concentração de butirato na torta de moringa à 50% em substituição à cana-de-açúcar. Em nível de 70%, a torta de moringa apresentou maior redução no metano e na energia alimentar. Em nível de substituição de 50%, a torta de algodão foi a substituição mais adequada para a canade-açúcar, a fim de reduzir a produção de gases com efeito de estufa.