The objectives of the study were to evaluate the soil disturbances and manure dispersion created by the AerWay aerator in a silt loam soil; and to generate a calibrated and validated soil-tool model using Discrete Element Methods (DEM) that simulate the draft and vertical forces of the aerator. The experimental results showed that a trend indicated that the faster tractor speeds would disturb more soil. After one hour with the manure application rate of 42 000 L/ha, manure was spread to a depth of 250 mm, 200 mm in the forward direction and 100 mm in the lateral direction. The model draft forces had a relative error of 13.4-31.2% when compared to the literature data between 100-150 mm depth while the predicted vertical force was found to linearly increase until 150 mm depth at around 700 N per rolling tine and plateaus until the full insertion of 200 mm.

The objectives of the study were to evaluate the soil disturbances and manure dispersion created by the AerWay aerator in a silt loam soil; and to generate a calibrated and validated soil-tool model using Discrete Element Methods (DEM) that simulate the draft and vertical forces of the aerator. The experimental results showed that a trend indicated that the faster tractor speeds would disturb more soil. After one hour with the manure application rate of 42 000 L/ha, manure was spread to a depth of 250 mm, 200 mm in the forward direction and 100 mm in the lateral direction. The model draft forces had a relative error of 13.4-31.2% when compared to the literature data between 100-150 mm depth while the predicted vertical force was found to linearly increase until 150 mm depth at around 700 N per rolling tine and plateaus until the full insertion of 200 mm.

The Canadian livestock industry generates 150 million tonnes of manure annually and the majority of this manure is land applied. This practice allows the manure nutrients to be recycled to the soil crop system while improving soil fertility. However, land application of manure has the potential to negatively impact soil, water, and air quality if not managed properly. Microbial processes transform the manure nutrients into forms that are susceptible to leaching or volatilization. Balancing the nutrient loss dynamics from fertilized soil is very difficult because the nutrient transformations are affected by the soil environment such as air and water content, pH, and labile carbon content. All of these soil environmental factors can be influenced by manure application practices such as application rate, timing, and manure placement. Knowledge of how these management practices affect the soil environment can help producers make management decisions that reduce the likelihood of soil, water, and air contamination from manure application.<p> Very few data exist on how manure application practices affect odour emissions after spreading. Therefore, the efficiency of subsurface application in reducing odours from manure spreading for both solid and liquid manure was assessed. Flux chambers and dynamic dilution olfactometry were used to measure odour emissions from five livestock manure species applied at three application rates using surface and subsurface application methods. The results indicated that odour concentrations from injected plots were up to 66% (37% on average) lower than concentrations from broadcast applications. Injection seemed to have a larger impact on reducing odours from solid manure than liquid manure, mainly due to efficient manure coverage from solid manure injection. Odours measured immediately after solid manure applications were also 37% lower than from liquid manure applications. In general, odours from both manure types increased with higher application rates, but there was little difference in the odours among low, mid, and high application rates. The specific odour rate (odour emission rate per kg N applied) decreased with application rate due to the reduced surface area available for volatilization of compounds with higher application rates. Based on these results, injection of manure is an effective way to reduce the odour emissions immediately after spreading, particularly for solid manure. However, other factors associated with manure injection, such as the increased power requirement and soil disturbance must be considered when evaluating the overall impact of manure injection versus surface application.<p> The odour data collected in this study described how management practices affected odours immediately after spreading. Knowledge of how these practices affect the emission rate trend over time is required to apply dispersion models to optimize the minimum separation distances for manure spreading activities. The model parameters for an existing volatilization model were determined from field and literature data and the resulting model allowed the effects of application mode (surface vs. subsurface) and manure type (liquid vs. solid) on odour emissions for 48 hours after application to be simulated. The effects of injection depth and a coverage factor on emissions were also simulated. The modeled peak fluxes from liquid manure applications were higher than those for solid manure applications, but the extended duration of odour emissions from solid manure resulted in higher cumulative losses from solid manure applications. While the application rate had no effect on the initial odour flux, higher application rates resulted in higher peak fluxes, higher overall emissions, and longer odour durations for both manure types and application methods. Modest injection depths were shown to reduce odours from both liquid and solid manure applications compared to surface spreading. The percent reductions in cumulative odours due to injection were estimated assuming typical coverage factors. The general predictions of the model developed in this study agree reasonably well with odour emission rate trends reported in literature. Future work should focus on better estimation of the model parameters and the variation of effective diffusivity with time and soil conditions.<p> Greenhouse gas (GHG) emissions from agricultural activities such as land application of livestock manure cannot be ignored when assessing overall emissions from anthropogenic sources. Like odour emissions, the magnitude of the GHG emissions will be influenced by management practices such as manure placement during land application. The GHG fluxes resulting from the surface and subsurface application of liquid and solid manure were also compared within 24 hours of application using a static chamber and gas chromatography. The results showed that carbon dioxide equivalent (CO2-e) fluxes were approximately three times higher from the injected plots than the surface plots for both solid and liquid manure. The elevated CO2-e fluxes were mainly due to a pronounced increase in N2O fluxes which was likely caused by increased denitrification rates. The CO2-e fluxes from the liquid manure applications were also approximately three times higher than the CO2-e fluxes from the solid manure applications, probably due to higher levels of ammonium available for nitrification and subsequent denitrification. The CH4 fluxes were generally low and the treatments had no effect. The measured specific fluxes (total flux per kg N applied) remained relatively constant with application rate, indicating that, in this study, GHG emissions from manure applications were approximately proportional to the amount of land applied manure.<p> While the data from this study showed that manure type and placement influenced short-term nitrous oxide (N2O) emissions, manure management practices (particularly slurry injection or solid manure incorporation) have the potential to influence long-term emissions by changing the magnitude and pattern of the nitrogen cycle in the soil-plant system. Management practices also impact the magnitude of other nitrogen losses (ammonia volatilization, nitrate leaching) which affect indirect N2O emissions. A model that simulates the environmental conditions and nutrient transformations after manure application may allow a more reliable prediction of the effect of management practices on total GHG emissions. Numerous process-based models have been used to estimate N2O emissions as influenced by agricultural practices in Canada. However, these models do not account for enhanced denitrification that potentially exists after slurry injection or manure incorporation, resulting in an underestimation of N2O emissions. A simple mass balance of nitrogen after application to land showed that enhanced denitrification can increase total N2O-N emissions by a factor of 5. By accounting for the increased microbial activity, slower oxygen diffusion and higher water filled pore space that exists after manure injection, models may better estimate N2O emissions from manure application practices.

The Canadian livestock industry generates 150 million tonnes of manure annually and the majority of this manure is land applied. This practice allows the manure nutrients to be recycled to the soil crop system while improving soil fertility. However, land application of manure has the potential to negatively impact soil, water, and air quality if not managed properly. Microbial processes transform the manure nutrients into forms that are susceptible to leaching or volatilization. Balancing the nutrient loss dynamics from fertilized soil is very difficult because the nutrient transformations are affected by the soil environment such as air and water content, pH, and labile carbon content. All of these soil environmental factors can be influenced by manure application practices such as application rate, timing, and manure placement. Knowledge of how these management practices affect the soil environment can help producers make management decisions that reduce the likelihood of soil, water, and air contamination from manure application.<p> Very few data exist on how manure application practices affect odour emissions after spreading. Therefore, the efficiency of subsurface application in reducing odours from manure spreading for both solid and liquid manure was assessed. Flux chambers and dynamic dilution olfactometry were used to measure odour emissions from five livestock manure species applied at three application rates using surface and subsurface application methods. The results indicated that odour concentrations from injected plots were up to 66% (37% on average) lower than concentrations from broadcast applications. Injection seemed to have a larger impact on reducing odours from solid manure than liquid manure, mainly due to efficient manure coverage from solid manure injection. Odours measured immediately after solid manure applications were also 37% lower than from liquid manure applications. In general, odours from both manure types increased with higher application rates, but there was little difference in the odours among low, mid, and high application rates. The specific odour rate (odour emission rate per kg N applied) decreased with application rate due to the reduced surface area available for volatilization of compounds with higher application rates. Based on these results, injection of manure is an effective way to reduce the odour emissions immediately after spreading, particularly for solid manure. However, other factors associated with manure injection, such as the increased power requirement and soil disturbance must be considered when evaluating the overall impact of manure injection versus surface application.<p> The odour data collected in this study described how management practices affected odours immediately after spreading. Knowledge of how these practices affect the emission rate trend over time is required to apply dispersion models to optimize the minimum separation distances for manure spreading activities. The model parameters for an existing volatilization model were determined from field and literature data and the resulting model allowed the effects of application mode (surface vs. subsurface) and manure type (liquid vs. solid) on odour emissions for 48 hours after application to be simulated. The effects of injection depth and a coverage factor on emissions were also simulated. The modeled peak fluxes from liquid manure applications were higher than those for solid manure applications, but the extended duration of odour emissions from solid manure resulted in higher cumulative losses from solid manure applications. While the application rate had no effect on the initial odour flux, higher application rates resulted in higher peak fluxes, higher overall emissions, and longer odour durations for both manure types and application methods. Modest injection depths were shown to reduce odours from both liquid and solid manure applications compared to surface spreading. The percent reductions in cumulative odours due to injection were estimated assuming typical coverage factors. The general predictions of the model developed in this study agree reasonably well with odour emission rate trends reported in literature. Future work should focus on better estimation of the model parameters and the variation of effective diffusivity with time and soil conditions.<p> Greenhouse gas (GHG) emissions from agricultural activities such as land application of livestock manure cannot be ignored when assessing overall emissions from anthropogenic sources. Like odour emissions, the magnitude of the GHG emissions will be influenced by management practices such as manure placement during land application. The GHG fluxes resulting from the surface and subsurface application of liquid and solid manure were also compared within 24 hours of application using a static chamber and gas chromatography. The results showed that carbon dioxide equivalent (CO2-e) fluxes were approximately three times higher from the injected plots than the surface plots for both solid and liquid manure. The elevated CO2-e fluxes were mainly due to a pronounced increase in N2O fluxes which was likely caused by increased denitrification rates. The CO2-e fluxes from the liquid manure applications were also approximately three times higher than the CO2-e fluxes from the solid manure applications, probably due to higher levels of ammonium available for nitrification and subsequent denitrification. The CH4 fluxes were generally low and the treatments had no effect. The measured specific fluxes (total flux per kg N applied) remained relatively constant with application rate, indicating that, in this study, GHG emissions from manure applications were approximately proportional to the amount of land applied manure.<p> While the data from this study showed that manure type and placement influenced short-term nitrous oxide (N2O) emissions, manure management practices (particularly slurry injection or solid manure incorporation) have the potential to influence long-term emissions by changing the magnitude and pattern of the nitrogen cycle in the soil-plant system. Management practices also impact the magnitude of other nitrogen losses (ammonia volatilization, nitrate leaching) which affect indirect N2O emissions. A model that simulates the environmental conditions and nutrient transformations after manure application may allow a more reliable prediction of the effect of management practices on total GHG emissions. Numerous process-based models have been used to estimate N2O emissions as influenced by agricultural practices in Canada. However, these models do not account for enhanced denitrification that potentially exists after slurry injection or manure incorporation, resulting in an underestimation of N2O emissions. A simple mass balance of nitrogen after application to land showed that enhanced denitrification can increase total N2O-N emissions by a factor of 5. By accounting for the increased microbial activity, slower oxygen diffusion and higher water filled pore space that exists after manure injection, models may better estimate N2O emissions from manure application practices.

No description available.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-07T14:38:13Z No. of bitstreams: 1 PGCS16MA152.pdf: 1026343 bytes, checksum: 9aece6d47b63a39320a6d4385220f021 (MD5) / Made available in DSpace on 2018-03-07T14:38:13Z (GMT). No. of bitstreams: 1 PGCS16MA152.pdf: 1026343 bytes, checksum: 9aece6d47b63a39320a6d4385220f021 (MD5) Previous issue date: 2016-09-30 / Many of the existing swine production systems in southern Brazil, provide high production of pig slurry. This situation leads to management problems, storage, distribution and environmental pollution caused by the improperly disposal of this waste product. The objective of this work was to determine the effect of application of dose increase of pig slurry on physical and chemical attributes of a Cambisol, in the production of plant biomass and water erosion, under three crops and compare the results with those obtained in soil condition uncultivated and without waste, in Rio do Sul - SC. The treatments were the control (no tillage and zero dose) and the doses 0 (zero), 50, 100 and 200 m³ ha-¹ of pig slurry applied on the soil surface. The application was performed in three stages after the implementation of millet, oat and sunn hemp in plots of 15 x 2.0 m, bounded by galvanized sheet, with an average gradient of 23.3%. The samples of erosive rainfall were collected to quantify the soil loss, water and nutrients. Before and after the experiment, soil samples were collected to evaluate the physical and chemical properties. At the end of each cultivation, dry matter production of shoot was determined. The increase of pig slurry doses increased production of biomass in the cultivated area, due to the improved porosity and, in part, of calcium, phosphorus and potassium, especially in the soil surface. Therefore, the water erosion reduces, after three cycles of cultivation. Soil losses were more influenced than the loss of water. The Ca, Mg, P and K contents in runoff water are the largest in treatments with higher doses of pig slurry. In the 200-m3 h-1 of pig slurry dose, the total nutrients losses in runoff are greatest / A erosão hídrica é a principal causa de degradação do solo agrícola e do ambiente no entorno dos sistemas de produção, fortemente influenciada pelo manejo do solo que, por sua, vez, é influenciando pelas adubações, dentro outros fatores. A maior parte dos sistemas de produção de suínos no sul do Brasil propicia produção de dejeto em alta quantidade. O dejeto gera problemas de manejo, armazenamento, distribuição e poluição ambiental causada pela erosão hídrica devido ao descarte do produto de forma de adubação, de maneira inadequada. Com o experimento objetivou-se estudar o efeito de dejeto líquido de suínos (DLS) em atributos de um Cambissolo Háplico, na produção de massa vegetal da parte aérea das plantas (MS) e na erosão hídrica em solo cultivado, e comparar os resultados com os obtidos em condição de solo sem cultivo e sem dejeto, em Rio do Sul - SC. Os tratamentos foram constituídos em testemunha (sem cultivo e sem dejeto) e pelas doses 0 (zero), 50, 100 e 200 m³ ha- ¹ de DLS aplicado na superfície do solo em três momentos após a implantação das culturas de milheto, aveia preta e crotalária, em parcelas de 15 x 2,0 m delimitadas por chapas galvanizadas, com declividade média de 23,3%. Ao longo da pesquisa foram determinadas as perdas de água e solo por erosão e coletadas amostras de enxurrada resultantes de chuvas erosivas para, nelas, determinar as perdas de alguns nutrientes. Antes da instalação do experimento e após o final da pesquisa, amostras de solo foram coletadas para avaliar as propriedades físicas e químicas e, ao final de cada cultivo, determinou-se ainda a produção de MS das plantas cultivadas no experimento. Identificou-se que o DLS aumentou a MS com o aumento da dose de dejeto, devido à melhoria da porosidade e, em parte, dos teores de cálcio, fósforo e potássio, em especial na superfície do solo. Com isso diminuiu a erosão hídrica ao final de três ciclos de cultivo. Em relação à erosão, as perdas de solo (PS) foram mais influenciadas do que as perdas de água (PA); os teores de Ca, Mg, P e K na água de escoamento superficial foram maiores nos tratamentos com as maiores doses de DLS do que naqueles das menores doses. As perdas totais de nutrientes na enxurrada, no entanto, foram maiores apenas na dose 200 m3 ha-1 de dejeto do que nas demais

The expansion of livestock husbandry and biogas production in large parts of northwestern Germany during the last two decades increased the amount of accruing manure, as well as the demand for maize as fodder crop and substrate for biogas plants. To overcome phosphorus deficiency symptoms during early growth of maize, farmers commonly apply mineral starter fertilizers containing ammonium-nitrogen and phosphorus on top of the usual manure applications required to meet crop nutrient demand. This practice typically leads to overfertilization of N and P and the excess nutrients are then prone to be lost into the environment. Recent developments of agricultural machinery allow for the injection of slurry bands into the soil prior to maize planting. Due to high concentrations of ammonium and phosphorus in the manure band, chemical transformation and translocation of these nutrients is reduced. When the bands are placed near the seeds, even the radicles can access the applied nutrients. Hence, application of mineral starter fertilizers might be obviated. Earlier investigations showed insufficient knowledge of nutrient transformations in manure bands and their consequences on crop growth. To resolve these problems a research project at the University of Applied Sciences Osnabrück was conducted in close cooperation with the local agricultural extension services, machinery producers and farmers. In a series of field trials, broadcasting of liquid manure was compared to injection with and without a nitrification inhibitor in three consecutive growing seasons (2013 to 2015). The trials were conducted in a split-plot design, where all liquid manure treatments were divided in subplots with and without a mineral starter fertilizer. Biomass samplings at eight leaves stage and harvest gave insight into the performance of the treatments. Compared to broadcast application with starter fertilizer, manure injection showed slightly retarded early growth in some trials. However, yields and nitrogen uptake at harvest were similar. When a nitrification inhibitor was added to the injected manure, early growth was not retarded, yields were alike broadcast and injection treatments, but nitrogen uptake was higher in all seasons (on average ~7%). To further investigate nitrogen dynamics and crop growth, another field trial was conducted on a sandy soil close to Osnabrück in 2014 and 2015. Manure injection with and without a nitrification inhibitor was compared to broadcast application with mineral starter fertilizer and an unfertilized control treatment. Plant samplings were taken at regular intervals. Major precipitation events in May and June 2014 led to significant nitrate leaching, especially in the broadcast treatment. Manure injection delayed the nitrification of slurry ammonium and consequently the translocation out of the root zone. Thus, plants in injection treatments could accumulate more nitrogen in their biomass and showed less nitrogen deficiency symptoms. This led to increased yield (+16.5%) and nitrogen uptake (+9.6%) for injection treatment with nitrification inhibitor compared to broadcast treatment. In 2015, low temperatures impaired seminal root growth and phosphorus availability. The mineral starter fertilizer in the broadcast treatment led to better early growth than injected slurry. When a nitrification inhibitor was added to the injected manure, less P deficiency symptoms were observed, and the crop growth was only slightly retarded. Due to the high compensation potential of silage maize, these differences were equalized until harvest. Nevertheless, the mean apparent nitrogen recovery efficiency of both seasons was higher in injection treatments with and without nitrification inhibitor, compared to broadcast with mineral starter fertilizer (48%, 56% and 43%, respectively). To ease the handling of field trial series by decreasing the number of tissue samplings, the use of a handheld sensor was tested during vegetative growth of maize. In the series of field trials with the local extension service, the derived vegetation index showed significant correlations to biomass and nitrogen uptake at eight leaves stage. Measurements of the vegetative growth observed during the nitrogen dynamics trial showed that the sensor needs sufficient leaf area to deliver precise data, but also tends to saturate when maize tassels evolve. The best estimates were found between six and ten leaves. Thus, the sensor can be a valuable tool to reduce numbers of tissue samples and, thus, time and effort needed in fertilization trials. Altogether, these results should encourage farmers to obviate mineral starter fertilizers by using manure injection when cropping maize on sandy soils. The advantages that come along with manure injection based on the present research indicate higher shares of manure nutrients find their way into the plants due to delayed biochemical transformations. These nutrients are consequently not lost into the environment. Nitrification inhibitors have shown a positive effect on crop performance and led to a further reduction of nitrogen losses. However, further knowledge of their decomposition with special regard to the ecological impact of their compounds and metabolites need to be thoroughly evaluated.

Grazing pasture is a major system of livestock production in many countries and it has been identified as an important source of N2O from urine deposition on soils. The aim of this study was to determinate the N2O emissions from soil after urine deposition and the emission factor, in addition, determine how temperature and water content of the soil influence these emissions. We also intended to study a potential of mitigation using nitrification inhibitors. Soil and gas samples were collected in traditional livestock areas in Brazil and UK to evaluate the N2O emission dynamics under field conditions. In addition, incubation experiments were conducted to evaluate how temperature and water content affect N2O emissions in the soil and to study the potential mitigation on N2O emission from the soil after urine application, using two distinct nitrification inhibitors. In the field experiment, the N2O emission factor for cattle urine was 0.20% of the applied urine N in Brazil and 0.66% for the UK conditions. The incubation experiments showed the N2O emissions after urine application are higher in soils with high moisture and high temperature. The nitrification inhibitor effectiveness was not statistically significant, however had shown some N2O emission absolute reductions among 6% to 33% comparing with urine only application on the soil. Various physical and biological factors can be influence the effectiveness of the products. It confirmed that urine deposition can contribute to N2O emission from the soil and the temperature and water content can markedly increase these emissions. The nitrification inhibitors have a potential mitigation effect since some decreased emissions of almost 40%. The results in this study are pioneers and can be used as a basis for more complex evaluations and to help with determining the carbon footprint of beef production worldwide / Considerado o maior sistema de produção animal em muitos países, as pastagens tem sido identificadas como uma importante fonte de emissão de N2O, devido à deposição de urina ao solo. O objetivo deste estudo foi determinar as emissões de N2O do solo após a deposição de urina e seu fator de emissão, além disso, determinar como temperatura e teor de água do solo influenciam as emissões. Pretendeu-se também estudar o potencial de mitigação das emissões de N2O usando inibidores de nitrificação. Amostras de solo e de gás foram coletadas em áreas tradicionais de pastagens do Brasil e do Reino Unido para avaliar a dinâmica das emissões de N2O. Experimentos de incubação também foram realizados para avaliar a influência de fatores como temperatura e teor de água no solo nas emissões, além de avaliar o potencial de redução das emissões de N2O do solo após a aplicação da urina, utilizando dois inibidores de nitrificação. Nos experimentos de campo realizados no Brasil e no Reino Unido, o fator de emissão do N2O para a urina foi de 0,20% e 0,66% do nitrogênio na forma de urina bovina aplicada, respectivamente. Nos experimentos de incubação, as emissões de N2O após a aplicação de urina foram maiores em solos com alta umidade e alta temperatura. A eficácia no uso dos inibidores de nitrificação não foi estatisticamente significativa, no entanto mostrou uma redução absoluta entre 6% a 33% nas emissões de N2O comparado com a aplicação de apenas urina ao solo. Vários fatores físicos e biológicos podem ter influenciado a eficácia dos produtos. Dessa forma, confirma-se que a deposição de urina pode contribuir para a emissão de N2O do solo e que a temperatura e o teor de água no solo podem aumentar consideravelmente essas emissões. Os inibidores de nitrificação podem ser usados como um potencial de mitigação, já que houve redução em termos absolutos de quase 40% nas emissões. Os resultados encontrados neste estudo são pioneiros e poderão ser utilizados como base para avaliações mais complexas e contribuir para a determinação da pegada de carbono na produção de carne mundial

Grazing pasture is a major system of livestock production in many countries and it has been identified as an important source of N2O from urine deposition on soils. The aim of this study was to determinate the N2O emissions from soil after urine deposition and the emission factor, in addition, determine how temperature and water content of the soil influence these emissions. We also intended to study a potential of mitigation using nitrification inhibitors. Soil and gas samples were collected in traditional livestock areas in Brazil and UK to evaluate the N2O emission dynamics under field conditions. In addition, incubation experiments were conducted to evaluate how temperature and water content affect N2O emissions in the soil and to study the potential mitigation on N2O emission from the soil after urine application, using two distinct nitrification inhibitors. In the field experiment, the N2O emission factor for cattle urine was 0.20% of the applied urine N in Brazil and 0.66% for the UK conditions. The incubation experiments showed the N2O emissions after urine application are higher in soils with high moisture and high temperature. The nitrification inhibitor effectiveness was not statistically significant, however had shown some N2O emission absolute reductions among 6% to 33% comparing with urine only application on the soil. Various physical and biological factors can be influence the effectiveness of the products. It confirmed that urine deposition can contribute to N2O emission from the soil and the temperature and water content can markedly increase these emissions. The nitrification inhibitors have a potential mitigation effect since some decreased emissions of almost 40%. The results in this study are pioneers and can be used as a basis for more complex evaluations and to help with determining the carbon footprint of beef production worldwide / Considerado o maior sistema de produção animal em muitos países, as pastagens tem sido identificadas como uma importante fonte de emissão de N2O, devido à deposição de urina ao solo. O objetivo deste estudo foi determinar as emissões de N2O do solo após a deposição de urina e seu fator de emissão, além disso, determinar como temperatura e teor de água do solo influenciam as emissões. Pretendeu-se também estudar o potencial de mitigação das emissões de N2O usando inibidores de nitrificação. Amostras de solo e de gás foram coletadas em áreas tradicionais de pastagens do Brasil e do Reino Unido para avaliar a dinâmica das emissões de N2O. Experimentos de incubação também foram realizados para avaliar a influência de fatores como temperatura e teor de água no solo nas emissões, além de avaliar o potencial de redução das emissões de N2O do solo após a aplicação da urina, utilizando dois inibidores de nitrificação. Nos experimentos de campo realizados no Brasil e no Reino Unido, o fator de emissão do N2O para a urina foi de 0,20% e 0,66% do nitrogênio na forma de urina bovina aplicada, respectivamente. Nos experimentos de incubação, as emissões de N2O após a aplicação de urina foram maiores em solos com alta umidade e alta temperatura. A eficácia no uso dos inibidores de nitrificação não foi estatisticamente significativa, no entanto mostrou uma redução absoluta entre 6% a 33% nas emissões de N2O comparado com a aplicação de apenas urina ao solo. Vários fatores físicos e biológicos podem ter influenciado a eficácia dos produtos. Dessa forma, confirma-se que a deposição de urina pode contribuir para a emissão de N2O do solo e que a temperatura e o teor de água no solo podem aumentar consideravelmente essas emissões. Os inibidores de nitrificação podem ser usados como um potencial de mitigação, já que houve redução em termos absolutos de quase 40% nas emissões. Os resultados encontrados neste estudo são pioneiros e poderão ser utilizados como base para avaliações mais complexas e contribuir para a determinação da pegada de carbono na produção de carne mundial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The environmental contamination by metallic trace elements is a problem that is getting worse around the world due to the growth and the technologic development of the humanity. Among the main sources of this kind of contamination are the atmospheric deposition of particles in soils located around industrial complexes and the prolonged and concentrated application of organic wastes in the soil. When present at the soil surface, these elements will migrate in depth and may reach the subsurface water bodies, causing their contamination. This study aimed to use the software Hydrus-2D to simulate the vertical redistribution of zinc, lead and copper in soil profiles contaminated by air pollution or by the application of swine liquid manure as well the transfer of these metallic trace elements into the groundwater. Chemical models were used under different hypotheses of reactivity of these elements with the soil particles and the physical, hidric and chemical characteristics of each soil profile. In the attempt to validate these models, it was simulated the vertical transports of zinc and lead, between 1900 and 2000, at three uses of a soil in northern France and of zinc and copper, between 2000 and 2008, at a soil profile located in Santa Maria RS, Brazil. Using a two sites chemical model with the kinetic constant decreased to 1% of the value measured in the laboratory, the simulations of the vertical transport of the metallic trace elements were validated in all soil profiles. This model was able to redistribute efficiently these elements in the profile, according their concentrations determined in situ. It was also predicted that the transfer of these contaminants do not represent, until now, any risk of pollution of the groundwater. Even with the continued application of high doses of swine liquid manure until 2058, the predicted increasing of zinc and copper concentrations in soil solution will not represent a risk of subsurface waters pollution. However, the model estimated that copper will be accumulated on the surface of this profile in greater quantities than zinc, increasing its concentration to levels above the value of intervention to agricultural areas. It was concluded that Hydrus-2D was a useful tool in detecting and/or forecasting environmental problems arising from the accumulation of metallic trace elements in soil and its leaching to the subsurface water bodies. / A contaminação do ambiente por elementos traços metálicos é um problema que vem se agravando em todo o mundo. Ela é decorrente do crescimento e do desenvolvimento tecnológico da humanidade, que apresenta, entre as principais fontes, as contaminações oriundas da deposição atmosférica de partículas aos solos localizados no entorno de complexos industriais e da aplicação concentrada e prolongada de resíduos orgânicos. Uma vez presentes na superfície do solo, esses elementos migrarão em profundidade, podendo atingir os corpos de água subsuperficiais e contaminá-los. Este trabalho teve por objetivo principal usar o programa computacional Hydrus-2D para simular a redistribuição vertical de zinco, chumbo e cobre no perfil de solos contaminados por poluição atmosférica ou pela aplicação de dejeto líquido de suínos e a transferência desses elementos traços metálicos rumo ao lençol freático. Para tal, foram usados modelos químicos sob diferentes premissas de reatividade dos elementos com as partículas do solo e as características físico-hídricas e químicas de cada perfil de solo. Buscou-se validar estes modelos, simulando os transportes verticais de zinco e chumbo, entre 1900 e 2000, em três usos de um solo do norte da França e de zinco e cobre, entre 2000 e 2008, num perfil de solo localizado em Santa Maria RS, Brasil. Utilizando um modelo químico de dois sítios com a constante cinética diminuída a 1% do valor medido em laboratório, as simulações do transporte vertical dos elementos traços metálicos foram validadas em todos os perfis de solo. Esse modelo foi capaz de redistribuir eficientemente estes elementos no perfil, conforme suas concentrações determinadas in situ. Ele também previu que a transferência destes contaminantes não representou, até o momento, nenhum risco de poluição da água do lençol freático. Mesmo com a manutenção da aplicação de altas doses de dejeto líquido de suínos até 2058, o aumento na concentração de zinco e cobre na solução do solo previsto não representará risco à poluição das águas subsuperficiais. Porém, o modelo estimou que o cobre se acumulará na superfície deste perfil em maior quantidade que o zinco, elevando sua concentração para níveis acima do valor de intervenção para áreas agrícolas. Dessa forma, o Hydrus-2D apresentou-se como uma ferramenta muito útil na detecção e/ou previsão de problemas ambientais decorrentes do acúmulo de elementos traços metálicos no solo e da sua lixiviação para os corpos de água subsuperficiais.