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Application of water treatment residuals (WTR) and biosolids (BS) might ameliorate fragile soils. However, studies integrating impacts of waste preparation methods such as liming and grinding associated with co-application approaches for soil conditioning are lacking. The present study aimed to evaluate the feasibility of agricultural use of WTR as well as their co-application with BS to ameliorate a sandy soil through assessing impacts on selected soil quality indicators and on nutrient and potentially toxic element concentration in plant tissue in addition to the biomass yield of annual crops. The following treatments were evaluated: non-amended soil (control); drying plus grinding and liming WTR; WTR co-application with BS at 3:1 ratio; and a soil amendment commercially available in Brazil. All treatments were soil incorporated in the 0.0?0.2 m layer at 30 Mg ha1 dose (dry mass). Selected soil physical, hydraulic, and chemical parameters were determined. Furthermore, nutrients and potentially toxic elements concentration in plant tissue as well as the agronomic performance of maize and ryegrass were measured. The co-application of WTR and BS increased the soil content of P, Zn, and Cu in the 0.0?0.1 m layer. The concentration of these nutrients also was greater in ryegrass tissue and promoted the biomass yield in 51%. WTR did not increase contaminants and did not decrease the P content in soil and in plant tissue, independently of drying plus grinding and liming. Considering the conditions investigated in our study, WTR/BS co-application was environmentally safe and effective in ameliorating soil quality. Made available in DSpace on 2022-03-10T02:04:40Z (GMT). No. of bitstreams: 1 Artigo-Liming-and-co8208application-of-water-treatment-residuals-with-biosolids-for-conditioning.pdf: 2784056 bytes, checksum: 1c8afdacd255cce09b35d8e88d3d9df9 (MD5) Previous issue date: 2022 First published: 17 January 2022.

A demanda mundial por alimentos tem contribuído para a expansão de novas fronteiras agrícolas em solos arenosos. Contudo, esses solos são frágeis e necessitam ser bem manejados de forma que possam expressar seu potencial produtivo. O objetivo deste estudo foi avaliar a qualidade física de um Neossolo Regolítico sob sistema de integração lavoura-pecuária no semiárido da Paraíba. 11 tratamentos foram avaliados em delineamento inteiramente casualizado, com cinco repetições. As amostras com estrutura indeformada foram coletadas nas camadas de 0-0,1 e 0,1-0,2 m e utilizadas na determinação da porosidade total (PT), Macroporosidade (Ma), microporosidade (Mi), porosidade de aeração (Pa), Densidade do solo (Ds), condutividade hidráulica saturada (Kθ), capacidade de campo (θCC), ponto de murcha permanente (θPMP), água disponível (θAD), granulometria e o grau de floculação (GF). Os dados foram analisados por meio da análise de variância e análise de componentes principais. O solo sob Floresta apresentou qualidade física do solo superior a muito dos tratamentos avaliados, contudo, melhorias físicas substanciais foram observadas no solo sob capim Massai, Urochloa decumbens e Urochloa decumbes + milho. Conclui-se que os atributos macroporosidade, condutividade hidráulica saturada e porosidade de aeração estão sendo pelos sistemas integrados de produção agropecuária.

Wastewater can be applied indiscriminately to the soil, bringing great discrimination, both to swine water and important to the soil and to swine water and important. In order to evaluate the polluting potential of different doses of swine wastewater, a soil study was carried out to study a two-ion project in dystroferric and its red argisols in dystroferric and its red argisols from Paraná (Brazil) and its influence on leachates generated. The analyzed treatments consist of a 2 x 2 x 2 factorial scheme for soil, doses and pH value. The experimental units were a total of 48 and the treatments were performed in triplicate. The application rates corresponded to 0, 50, 100 and 150 m-3.ha-1. The pH value of both soil and leachate remained in the acidic range, although the initial pH value of the soil and swine wastewater proved to be basic. The nutrient ion had more direct influence on the electrical conductivity of the leachates. The V% did not have a significant individual value due to the application of swine wastewater, so the CEC was high in the step in the argisol. The same occurred with ESP, showing that the nitosol was prone to salinization. Las aguas residuales porcinas aplicadas indiscriminadamente al suelo pueden causar grandes daños, tanto al suelo como a las aguas superficiales y subterráneas. Para evaluar el potencial contaminante de diferentes dosis de aguas residuales porcinas, se estableció una prueba de columna de suelo para estudiar la dinámica de los iones en dos suelos (nitosoil distroférrico rojo y argisol distrófico rojo) representativos del estado de Paraná (Brasil) y su influencia. el lixiviado generado. Los tratamientos analizados consistieron en un esquema factorial 2 x 4 x 2 para suelo, dosis y valor de pH. Las unidades experimentales fueron un total de 48 y los tratamientos se realizaron por triplicado. Las dosis de aplicación correspondieron a 0, 50, 100 y 150 m-3.ha-1. El valor de pH tanto del suelo como del lixiviado se mantuvo en el rango ácido, aunque el valor de pH inicial del suelo y las aguas residuales porcinas resultó ser básico. El ión que más lixivió fue el calcio, seguido del magnesio, sodio y potasio, y la lixiviación de estos nutrientes influyó directamente en la conductividad eléctrica de los lixiviados. Los valores de V% en el suelo tuvieron un cambio significativo debido a la aplicación de aguas residuales porcinas, mientras que la CIC fue alta en el nitosol y baja en el argisol. Lo mismo ocurrió con PSI, demostrando que el nitosol era propenso a la salinización. A água residuária de suinocultura aplicada indiscriminadamente ao solo pode trazer grandes prejuízos, tanto ao solo como às águas superficiais e subterrâneas. Para se avaliar o potencial poluente de diferentes doses de água residuária de suinocultura, montou-se um ensaio em colunas de solo para estudar a dinâmica de íons em dois solos (nitossolo vermelho distroférrico e argissolo vermelho distrófico) representativos do estado do Paraná (Brasil) e sua influência nos lixiviados gerados. Os tratamentos analisados consistiram em um esquema fatorial 2 x 4 x 2 para solo, doses e valor de pH. As unidades experimentais foram de um total de 48 e os tratamentos foram realizados em triplicata. As taxas de aplicação corresponderam a 0, 50, 100 e 150 m-3.ha-1. O valor de pH, tanto do solo como dos lixiviados, ficaram na faixa ácida, embora o valor de pH inicial do solo e da água residuária de suinocultura mostrou-se básico. O íon que mais lixiviou foi o cálcio, seguido pelo magnésio, sódio e potássio, sendo que a lixiviação desses nutrientes teve influência direta na condutividade elétrica dos lixiviados. Os valores de V% no solo tiveram alteração significativa em virtude da aplicação da água residuária de suinocultura, ao passo que a CTC foi alta no nitossolo e baixa no argissolo. O mesmo ocorreu com o PST, evidenciando que o nitossolo se mostrou propenso à salinização.

Process-based models (PBM) are important tools for understanding the benefits of Integrated Crop-Livestock Systems (ICLS), such as increasing land productivity and improving environmental conditions. PBM can provide insights into the contribution of agricultural production to climate change and help identify potential greenhouse gas (GHG) mitigation and carbon sequestration options. Rehabilitation of degraded lands is a key strategy for achieving food security goals and can reduce the need for new agricultural land. This study focused on the calibration and validation of the DayCent PBM for a typical ICLS adopted in Brazil from 2018 to 2020. We also present the DayCent parametrization for two forage species (ruzigrass and millet) grown simultaneously, bringing some innovation in the modeling challenges. We used aboveground biomass to calibrate the model, randomly selecting data from 70% of the paddocks in the study area. The calibration obtained a coefficient of determination (R2) of 0.69 and a relative RMSE of 37.0%. During the validation, we used other variables (CO2 flux, grain biomass, and soil water content) measured in the ICLS and performed a double validation for plant growth to evaluate the robustness of the model in terms of generalization. R2 validations ranged from 0.61 to 0.73, and relative RMSE from 11.3 to 48.3%. Despite the complexity and diversity of ICLS results show that DayCent can be used to model ICLS, which is an important step for future regional analyses and large-scale evaluations of the impacts of ICLS. Made available in DSpace on 2022-03-17T18:00:45Z (GMT). No. of bitstreams: 1 AP-Intense-Pasture-2022.pdf: 4965215 bytes, checksum: 97d06087ad171d3a5e76317d8f5dcbc8 (MD5) Previous issue date: 2022 Article 3517.

Renewable energy produced from sugarcane (Saccharum spp.) has clear advantages over fossil fuels in mitigating climate change. However, N2O emissions and NO3− leaching from fertilizer nitrogen (N) addition can jeopardize the sustainability of sugarcane production worldwide. One of the possible approaches to mitigating these N-loss pathways is the use of nitrification inhibitors such as dicyandiamide (DCD). However, the effects of DCD on the fate of fertilizer-derived N in soil pools and functional N genes (e.g., nitrifiers and denitrifiers) remain unclear. We performed a laboratory incubation study for 54 days to evaluate the influence of DCD and fertilizer N rate ((15NH4)2SO4 applied at 40, 80, 120, and 160 µg N g−1) on 15N transformation and abundance of total prokaryotes (16S rRNA), nitrifiers (ammonia-oxidizing archaea (AOA) and bacteria (AOB)), and denitrifiers (nirK and nosZ) in a tropical sandy soil amended with sugarcane residues. Especially for high N rates (120 and 160 µg N g−1), DCD not only increased the NH4+-15N recovery by inhibiting nitrification but also stimulated microbial immobilization. However, the nitrification inhibitor decreased N losses (i.e., unrecovered 15N). The abundance of total archaea and bacteria was unaffected by both the fertilizer N rate and DCD. While the abundance of AOB and nirK was suppressed by DCD, AOA and nosZ abundance increased, with the latter gene being the highest at 160 µg g−1. We conclude that DCD mitigates N losses from ammonium-based fertilizer by inhibiting NO3− production and changing nitrifying and denitrifying microorganisms in sandy acidic soil.

The diversity of soils and climate in Brazil imposes the need to evaluate the adaptation of fodder species to soil and climate conditions to guide producers and technicians in choosing the best alternatives for their region. The objective of this study was to evaluate and identify fodder cultivars for pasture and soil cover with tolerance to drought and high production in the sandy soils of southern Bahia, Brazil. The performance of 29 commercial cultivars of perennial and annual tropical forage species was evaluated in six cuts in 2019 and 2020. The green and dry mass yield per cut and the daily dry matter accumulation rate were evaluated considering the periods of water surplus and deficit and the drought tolerance index for each cultivar was estimated. Grass and legume cultivars showed differences in establishment, yield in the water surplus, and in the re-establishment after the water deficit. Based on the values of the drought tolerance index and in the dry mass daily yields before and after the water deficit, the cultivars adapted and indicated for regional continuous grazing were Xaraés, Marandu, Massai, Tanzânia, Paiaguás, and Zuri, in that order. The grasses B. ruziziensis and B. decumbens were indicated for use as cover plants after the harvest due to their high capacity of establishment and short-term production. The annual and perennial legume plants were also indicated for cover, and the combination of cultivars and their potential for straw in direct planting or use in integrated systems still need to be validated. The diversity of soils and climate in Brazil imposes the need to evaluate the adaptation of fodder species to soil and climate conditions to guide producers and technicians in choosing the best alternatives for their region. The objective of this study was to evaluate and identify fodder cultivars for pasture and soil cover with tolerance to drought and high production in the sandy soils of southern Bahia, Brazil. The performance of 29 commercial cultivars of perennial and annual tropical forage species was evaluated in six cuts in 2019 and 2020. The green and dry mass yield per cut and the daily dry matter accumulation rate were evaluated considering the periods of water surplus and deficit and the drought tolerance index for each cultivar was estimated. Grass and legume cultivars showed differences in establishment, yield in the water surplus, and in the re-establishment after the water deficit. Based on the values of the drought tolerance index and in the dry mass daily yields before and after the water deficit, the cultivars adapted and indicated for regional continuous grazing were Xaraés, Marandu, Massai, Tanzânia, Paiaguás, and Zuri, in that order. The grasses B. ruziziensis and B. decumbens were indicated for use as cover plants after the harvest due to their high capacity of establishment and short-term production. The annual and perennial legume plants were also indicated for cover, and the combination of cultivars and their potential for straw in direct planting or use in integrated systems still need to be validated.

Intensive management of forest stands can increase biomass production, as well as increase the removal of nutrients from the site. This study therefore sought to simulate different harvest intensities and to calculate the nutrient-use efficiency of Eucalyptus urograndis in different types of soil. The study was carried out in a plantation of seven-year-old hybrid E. urograndis in the city of Telêmaco Borba, Paraná, Brazil. The study site included two sub areas with sandy soil and clayey soil (Cambisols Inceptisol and Ferralsols Oxisols, respectively). Using biomass and nutrients stock data, nutrient removal was simulated under five different harvest scenarios. Nutrient-use efficiency was obtained from the relation between the amount of biomass and nutrients of each tree component. Harvesting the whole tree resulted in the removal of approximately 61% of the nutrients from the site in sandy soil, while in clayey soil 57% of the nutrients were removed. With harvesting of only the commercial stemwood, only 22% of the nutrients were removed from the sandy soil, and 21% from the clayey soil. Stemwood was the component that had the highest nutrient-use efficiency values for all the analyzed nutrients. In conclusion, to achieve nutritional sustainability of E. urograndis stands, the best harvesting system involves the removal of only commercial stemwood. For the production of stemwood, sandy soils have a greater biological efficiency of calcium and magnesium when compared to clayey soil. Resumo O manejo intensivo de povoamentos florestais pode aumentar a produção de biomassa, bem como aumentar a remoção de nutrientes do local. Assim, o objetivo deste estudo foi simular diferentes intensidades de colheita e calcular a eficiência de utilização de nutrientes para Eucalyptus urograndis em diferentes tipos de solo. O estudo foi realizado em um plantio do híbrido E. urograndis de sete anos de idade, no município de Telêmaco Borba, Paraná, Brasil. O local de estudo incluiu duas subáreas com solo arenoso e solo argiloso (Cambissolo Háplico e Latossolo Vermelho, respectivamente). Com os dados de estoque de biomassa e nutrientes foi simulada a remoção de nutrientes em cinco cenários de colheita diferentes. A eficiência de utilização de nutrientes foi obtida a partir da relação entre a quantidade de biomassa e os nutrientes de cada componente da árvore. A colheita da árvore inteira resultou na retirada de aproximadamente 61% dos nutrientes do local em solo arenoso, enquanto em solo argiloso, 57% dos nutrientes foram removidos. Com a colheita apenas da madeira do fuste comercial, apenas 22% dos nutrientes foram retirados do solo arenoso e 21% do solo argiloso. A madeira do caule foi o componente que apresentou os maiores valores da eficiência de utilização de nutrientes para todos os nutrientes analisados. Para alcançar a sustentabilidade nutricional dos povoamentos de E. urograndis, o melhor sistema de colheita envolve a remoção apenas da madeira do tronco comercial. Para a produção de madeira, os solos arenosos apresentam maior eficiência biológica de cálcio e magnésio quando comparados aos solos argilosos.

Soils attributes such as granulometry and density determine the distribution of pore size and condition physical and differentiated hydraulic behavior. Thus, knowing the characteristics of the soils allow the use of more adequate management techniques that lead to the improvement of the performance of the use of this resource. The aim of this study was to evaluate the diameters of granulometric fractions and the physical-hydric behavior of sandy soils from semiarid region of Brazil. Trenches were excavated to collect, describe, and characterize the morphology of soil samples. The soil bulk density, particle density, granulometry, water retention curve, total porosity and pore size distribution were evaluated. The textural difference among soil studied is expressed with greater emphasis on the amount of macropores, high retention micropores and cryptopores. Fine and very fine sand are the most impacted granulometric fractions increasing macroporosity and reducing high tension microporosity and cryptoporosity. Luvisol with predominance of silt and clay fractions, presents a greater risk of densification and erosion, thus the use of lower irrigation levels is recommended. Acrisols and Luvisol, with predominance of fine and very fine sand fractions, present similar conditions of macroporosity and cryptopores with a low textural gradient. Acrisols and Luvisol do not present major problems regarding the reduction of hydraulic conductivity along the rofile. Lower irrigation levels with higher application frequency are suggested due to the low water retention capacity and higher risk nutrients leaching. Made available in DSpace on 2019-10-17T18:15:22Z (GMT). No. of bitstreams: 1 Granulometricfractions2019.pdf: 802903 bytes, checksum: 8c4738c1ca7d2caa2ef17fdb80ecd897 (MD5) Previous issue date: 2019

The inadequate agricultural management in the semiarid region of northeastern Brazil, associated with the fragility of most soils, has caused degradation of the quality of this resource. This study aimed to evaluate the quality of Quartzipsamments under different uses through the multivariate analysis of chemical and physical attributes. Five areas were selected: four of them with agricultural use (onion, banana, cassava, and corn) and the other with Caatinga. Soil samples were collected at depths of 0.00?0.10, 0.10?0.20, and 0.20?0.40 m for chemical and physical analyses. The data were submitted to descriptive analysis and then to the multivariate analysis using the principal component analysis (PCA) technique and Ward?s clustering method. PCA and clustering techniques allowed the identification of different production systems in subsurface layers, suggesting the effect of fertility on the differentiation of areas with onion and banana, as well as the clustering of cassava and corn cultivations. Physical attributes and sodium content of the surface layer of the area with onion showed a tendency of compaction and salinization process of this environment. In general, fertility was the main responsible for the improvement of soil quality with agricultural use when compared to the Caatinga Made available in DSpace on 2019-08-16T00:36:43Z (GMT). No. of bitstreams: 1 Multivariateanalysis2019.pdf: 948287 bytes, checksum: 98b3a9b61ec2c4c3f174c9d009868fad (MD5) Previous issue date: 2019

stract: The aim of this work is to define indices of soil chemical quality in intense agricultural activity area surrounding Sobradinho Lake, State of Bahia, Brazil, by means of multivariate statistical techniques. Based on the factor scores, it was determined soil chemical quality index for depths of 0-0.10, 0.10-0.20 and 0.20-0.40 m, respectively, classifying soils as good, fair and poor, according to the performance of its attributes. Then realized the Discriminative Analysis in order to validate the results obtained and, knowing the chemical soil attributes that influence and are associated with soil quality in agriculture of the region. In this way, among the main results could be observed that the attributes exchangeable sodium percentage (ESP) and organic matter (OM) stood out as indicators of soil quality. The ESP was the more important attribute in discrimination models in the depths of 0.00-0.10 and 0.10-0.20 m and OM in the 0.20-0.40 m layer. These variables are the main responsible for discrimination and classification of soil groups. In general, the chemical quality of soils is not considered ideal mainly due to the low contents OM and the extremely sandy texture, denoting environmental fragility. Made available in DSpace on 2018-12-05T23:51:40Z (GMT). No. of bitstreams: 1 artigosalvio2018agrarian.pdf: 594713 bytes, checksum: 622c444685c46d2d91fa95f8dc7298c2 (MD5) Previous issue date: 2018-12-05

O Campo Experimental de Araquari foi desenvolvido com o intuito de investigar os complexos mecanismos de interações entre estacas em um solo arenoso saturado. A partir dessas análises, ficou evidente que tais fenômenos são dependentes diretamente da resistência ao cisalhamento da interface, destacando os seus modelos mecânicos. Autores que abordam tais modelos, sugerem que os fatores mais relevantes para a mobilização de resistência da interface são rugosidade e rigidez da superfície do elemento estrutural, tamanho e formato dos grãos do solo e ainda procedimentos executivos adotados na escavação e concretagem. No entanto, trabalhos pioneiros, e mesmo estudos mais recentes referentes à interface, não abordam aspectos relacionados à tensão residual mobilizada na estaca devido aos efeitos da cura do concreto e sua importância na análise do comportamento de estacas. Nesse sentido, esta pesquisa foi desenvolvida com o objetivo de estudar e analisar, desde o início do processo de endurecimento do concreto, o comportamento da interface entre areias e o concreto da estaca a partir de ensaios em laboratório, buscando estabelecer as propriedades e parâmetros que se mostram mais relevantes e aplicá-los à reinterpretação da prova de carga da estaca ET02 do Campo Experimental de Araquari, considerando tensões residuais. Foram realizados ensaios de interface em duas areias distintas, Ottawa graded e Araquari, em diferentes tempos de cura (0,5; 3; 6; 9; 12 e 24 horas), e tensões de confinamento (100kPa, 200kPa e 300kPa), além de mensurar o perfil de rugosidade. Os resultados voltados à interface apontam que as medidas de rugosidade crescem com o aumento das tensões confinantes, sendo esse acréscimo mais pronunciado com o aumento do tamanho dos grãos. As relações entre o ângulo de atrito de pico da interface e do solo mostraram-se inferiores à 1 até o período de três horas de cura (fim estágio de endurecimento e início do estágio estável do concreto), tornando-se maiores à após esse tempo. Quanto a avaliação da geração de tensões residuais durante o processo de cura, foi observado que esse efeito é menor do que 10% da carga total na qual à estaca foi submetida. Ademais, conclui-se que o ângulo de atrito do estado crítico é o parâmetro mais adequado para ser utilizado projetos em estacas escavadas em solo arenoso. Ainda que, no que se refere a tensões residuais para pequeníssimas idades do concreto, o ângulo de atrito na interface possa ser menor do que o ângulo de atrito no estado crítico do solo, após o início do processo de endurecimento, a ruptura se dará sempre pelo solo e não mais pela interface. The Araquari Experimental Testing Site was developed to investigate the complex mechanisms of interactions between piles in a saturated sandy soil. In this sense, it was evident that such phenomena are directly dependent on the shear strength of the interface, highlighting mechanical interface models. Authors who approach such models, suggest that the most relevant factors for the mobilization of resistance of the interface are roughness and stiffness of the surface of the structural element, grain size and shape and, also, executive procedures adopted in the excavation and concreting process. However, pioneering work, and even more recent studies regarding the interface, do not approach aspects related to the residual stress mobilized in the pile due to the effects of concrete curing and its importance in the analysis of the pile behavior. Along those lines, this research was developed with the goal of studying and analyzing the behavior of the interface between sands and the concrete piles through laboratory tests, since the beginning of the concrete curing process, seeking to establish the properties and parameters that are shown more relevant and apply it to the reinterpretation of the load test of the ET02 pile at the Araquari Experimental Field. Interface tests were carried out on two different sands, Ottawa graded and Araquari, at different curing times (0.5; 3; 6; 9; 12 and 24 hours), and confinement stresses (100kPa, 200kPa and 300kPa). In addition, the roughness profile was measured. The results show that the roughness measurements increase proportionally of the confining stresses, being more pronounced with the increase of the grain size. The relationships between the peak friction angle of the interface and the soil up to three hours of curing (end of hardening stage and beginning of the stable concrete stage) are less than 1, becoming greater than 1 after this curing time. During the evaluation of the residual stresses created during the curing process, it was observed that this effect is less than 10% of the total load that the pile was subjected to. In addition, it is concluded that the critical friction angle of the sand must be used in bored piles projects. And yet, regarding residual stresses, for young ages of concrete, the friction angle at the interface may be less than the friction angle in the critical state of the soil. After the beginning of the curing process, the rupture will always occur through the soil and no longer through the interface.

Renewable energy produced from sugarcane (Saccharum spp.) has clear advantages over fossil fuels in mitigating climate change. However, N2O emissions and NO3− leaching from fertilizer nitrogen (N) addition can jeopardize the sustainability of sugarcane production worldwide. One of the possible approaches to mitigating these N-loss pathways is the use of nitrification inhibitors such as dicyandiamide (DCD). However, the effects of DCD on the fate of fertilizer-derived N in soil pools and functional N genes (e.g., nitrifiers and denitrifiers) remain unclear. We performed a laboratory incubation study for 54 days to evaluate the influence of DCD and fertilizer N rate ((15NH4)2SO4 applied at 40, 80, 120, and 160 µg N g−1) on 15N transformation and abundance of total prokaryotes (16S rRNA), nitrifiers (ammonia-oxidizing archaea (AOA) and bacteria (AOB)), and denitrifiers (nirK and nosZ) in a tropical sandy soil amended with sugarcane residues. Especially for high N rates (120 and 160 µg N g−1), DCD not only increased the NH4+-15N recovery by inhibiting nitrification but also stimulated microbial immobilization. However, the nitrification inhibitor decreased N losses (i.e., unrecovered 15N). The abundance of total archaea and bacteria was unaffected by both the fertilizer N rate and DCD. While the abundance of AOB and nirK was suppressed by DCD, AOA and nosZ abundance increased, with the latter gene being the highest at 160 µg g−1. We conclude that DCD mitigates N losses from ammonium-based fertilizer by inhibiting NO3− production and changing nitrifying and denitrifying microorganisms in sandy acidic soil.

The central region of Brazil is its current agricultural frontier, with rapid expansion of soy, coffee and cotton crops under sandy soils. One of the major management challenges for this type of soil is the reduction of its low natural fertility and maintenance of humidity. This work had the objective of evaluating the applicability of the use of Soil Penetration Radar (GPR) in the determination of attributes of sandy soils in the central part of Brazil. The study was carried out in the southeastern state of Bahia, in an area of ​​flat relief and under pasture. Two complete profiles were sampled, whose samples were analyzed chemically and physically. The reading was performed in transects with lengths over 500m. GPR equipped with a 400 MHz antenna was used. The Topp, Ledieu and Condé equations were applied to determine the gravimetric humidity from the dielectric constant values ​​obtained from the radargrams. It was observed that these are deep soils, without physical impediments and that there is an increase in humidity in depth., A região central do Brasil é a sua atual fronteira agrícola, com rápida expansão das culturas de soja, café e algodão sob solos arenosos. Um dos grandes desafios de manejo desse tipo de solo é a redução da sua baixa fertilidade natural e manutenção da umidade. Esse trabalho teve o objetivo de avaliar a aplicabilidade do uso de Radar de Penetração do Solo (GPR) na determinação de atributos de solos arenosos da parte central do Brasil. O estudo foi realizado no sudeste do estado da Bahia, numa área de relevo plano e sob pastagem. Foram amostrados dois perfis completos, cujas amostras foram analisadas química e fisicamente. A leitura foi realizada em transectos com comprimento acima de 500m. Foi utilizado GPR equipado com antena de 400 MHz. Foram aplicadas as equações de Topp, Ledieu e Condé para determinação da umidade gravimétria a partir de valores de constante dielétrica obtidas dos radargramas. Foi observado tratar-se de solos profundos, sem impedimentos físico e que apresenta aumento da umidade em profundidade.

A técnica de melhoramento de solos é muito frequente diante de obras geotécnicas, entretanto a prática de solos artificialmente cimentados comumente faz uso de agentes químicos tradicionais, como o cimento Portland e a cal. Sob o ponto de vista ambiental, estes materiais não são considerados tecnicamente sustentáveis, o que atualmente torna-se uma grande preocupação. Conciliar a sustentabilidade e o desenvolvimento de novos materiais é, sem dúvidas, essencial para progredirmos em sociedade. Os cimentos álcali ativados surgiram recentemente, e são um potencial substituto aos materiais tradicionais. Isto se deve a possibilidade de utilizar resíduos e subprodutos, industriais e/ou domésticos, como precursores e ativadores para a produção, logo, a emissão de CO2 e o consumo de energia são ínfimos. A presente pesquisa visa o emprego de dois resíduos para a técnica de ativação alcalina através da cerâmica vermelha, provenientes da indústria de construção e demolição, e a cal de carbureto, subproduto da produção de gás acetileno, ativados com soluções de hidróxido de sódio. Este novo material cimentante é utilizado como fonte de estabilização de um solo granular uniforme, onde é avaliado o desempenho perante aos ensaios de resistência à compressão simples, resistência à tração por compressão diametral, rigidez inicial, durabilidade por ciclos de molhagem e secagem e módulo de resiliência. Ainda, buscou-se por uma análise mineralógica através de DRX para verificar os produtos de reação formados nesta estabilização. As variações da porosidade, do teor de agente cimentante utilizado, do teor de umidade de moldagem e do tempo de cura afetam significativamente o comportamento de todas as variáveis respostas, onde a resistência à compressão simples atingiu valores de 4,23 MPa aos 7 dias de cura e, 7,62 MPa aos 28 dias de cura. Pode-se perceber que há uma relação íntima entre o teor de agente cimentante e o teor de umidade de moldagem, os quais resultam em um impacto negativo quando considerada certas dosagens, em todos os ensaios. Diante disto, a análise mineralógica revelou a formação de um gel silicato de sódio e cálcio, o qual varia de intensidade conforme as variáveis controláveis. Por fim, foi possível relacionar os dados obtidos com a relação entre porosidade/teor volumétrico de agente cimentante, se mostrando adequada e compatível com a previsão do desempenho mecânico e que combinação dos materiais utilizados para a estabilização apresentam potencial para a utilização como camada de pavimento. The soil improvement technique is very common in geotechnical works, however the practice of artificially cemented soils commonly aplly traditional chemical agents, such as Portland cement and lime. Considering the environmental impacts, these materials are not technically sustainable, which is currently a major concern. Reconciling sustainability and the development of new materials is undoubtedly essential for progress in society. Alkali-activated cements have recently appeared, and are a potential substitute for traditional materials. This is due to the possibility of using residues and by-products, industrial and/or domestic, as precursors and activators for production, therefore, CO2 emissions and energy consumption are very small. The present research aims to use two wastes for the alkali activation technique through red ceramics wastes, from the construction and demolition industry, and carbide lime, a by-product of the production of acetylene gas, activated with sodium hydroxide solutions. This new binder is used as a source of stabilization for a uniform granular soil, where performance is evaluated by unconfined compression strength, splitting tensile test, initial shear strength, durability wetting -drying cycles and resilient modulus. Moreover, the microstructure of a few blends was evaluated through X-ray diffraction tests (XRD) to identify the reactions products that are expected to be formed. The variation in porosity, binder content, moisture content and curing time significantly altered the behavior of response variables, results show that unconfined compressive strength varies to 4,23 MPa after 7 days curing time to 7,62 MPa after 28 days curing time. There is a relation between binder content and moisture content, which results in negative impact considering some blends. Therefore, the XRD analyses identified sodium calcium silicate as a cementitious gel formed by alkali-activated process. The relationship between porosity/volumetric binder content is adequate and compatible to estimate the mechanical response of the blends that are suitable to use as cemented materials for pavements.

A adsorção específica de fósforo nos minerais da fração argila do solo, como os oxi-hidróxidos de Fe e Al, é responsável pela diminuição da disponibilidade desse elemento para as plantas. No Brasil, a condição é estudada substancialmente em solos de textura média a muito argilosa, cuja atividade de adsorção é expressiva. O objetivo deste estudo foi avaliar a capacidade máxima de adsorção de fósforo (CMAP) em solos de textura arenosa com fertilidade construída no bioma Cerrado. Foram selecionadas áreas com os solos representativos nos municípios de Luís Eduardo Magalhães (LEM/BA) e Guaraí (TO), com as seguintes coberturas vegetais: a) LEM: vegetação natural e algodão; b) Guaraí: vegetação natural e soja. Foram coletadas amostras de solo nas camadas de 0 cm - 20 cm e 60 cm - 80 cm, nas quais foram realizadas as análises químicas e físicas de rotina, análises relativas à adsorção de fósforo, como o Prem e a CMAP e o PESN. Os teores de Prem são maiores na camada de 0 cm - 20 cm para a região de LEM. A CMAP é pouco expressiva nos solos das duas regiões estudadas, tendo os solos de Guaraí maior potencial relativo de adsorção pelos maiores valores da razão CMAP/argila. Made available in DSpace on 2022-03-09T12:00:47Z (GMT). No. of bitstreams: 1 Capacidade-de-adsorcao-de-fosforo-em-solos-2021.pdf: 335543 bytes, checksum: 230e4a605868c42e9a184985df887095 (MD5) Previous issue date: 2021

The specific adsorption of phosphorus in minerals from the clay fraction of the soil, such as Fe and Al oxyhydroxides, is responsible for the decrease in the availability of this element for plants. In Brazil, this condition is studied substantially in medium to very clayey textured soils, whose adsorption activity is expressive. The aim of this study was to evaluate the maximum phosphorus adsorption capacity (CMAP) in sandy-textured soils with fertility built in the Cerrado biome. Areas with representative soils were selected in the cities Luís Eduardo Magalhães (LEM / BA) and Guaraí (TO), with the following vegetation cover: a) LEM: natural vegetation and cotton; b) Guaraí: natural vegetation and soybean. Soil samples were collected in the 0-20 cm and 60-80 cm layers, in which chemical and physical analyzes were performed periodically, as well as analyzes related to phosphorus adsorption such as Prem and CMAP and PESN. Prem contents are higher in the 0-20 cm layer for the LEM region. The CMAP is not very expressive in the soils of the two studied regions, with the Guaraí soils having higher relative adsorption potential due to the higher values of the CMAP/clay ratio. Made available in DSpace on 2022-03-08T12:00:49Z (GMT). No. of bitstreams: 1 Phosphorus-adsorption-capacity-in-sandy-textured-soils-2021.pdf: 335341 bytes, checksum: d2bf1c06968d6f21408c7a0b4f52260f (MD5) Previous issue date: 2021

Resumen La necesidad de conocer la porosidad drenable del suelo o macroporosidad con fines de manejar correctamente el agua en el suelo, sea ésta con fines de riego o con fines de drenaje ha tomado cada vez mayor relevancia. Para ello existen equipos que se ofrecen en casas comerciales generalmente de costos altos. No obstante, conociendo la física del agua en una matriz arenosa se puede construir una mesa de succión (mesa de tensión) con arena llamada comúnmente caja de arena para estimar la macro y microporosidad y como tal la porosidad total presente en un suelo. Las micro porosidades obtenidas para un suelo arenoso expresado en contenido de humedad volumétrica sometido a una succión de 60 cmca (centímetros de columna de agua) y a 100 cmca fueron 11,12% y 5,73% respectivamente y las macro porosidades obtenidas y expresadas en términos de porcentaje de humedad volumétrica para un suelo arenoso sometido a una succión de 60 cmca y a 100 cmca fueron 25,14% y 30,53%. Abstract The need to know the drainable porosity of the soil or macro porosity in order to correctly manage the water in the soil, whether it is for irrigation purposes or for drainage purposes, has taken on increasing relevance. For this there are equipment that is offered in commercial houses, usually with high costs. However, knowing the physics of water in a sandy matrix, you can build a suction table (tension table) with sand commonly called sandbox to estimate the macro and micro porosity and as such the total porosity present in a soil. The micro porosity obtained for a sandy soil subjected to a suction of 60 cmca (centimeters of water column) and 100 cmca were 11,12% and 5,73% of gravimetric humidity and the macro porosity obtained and expressed in terms of percentage of gravimetric humidity ((gwater/gsoil) * 100) for a sandy soil subjected to a suction of 60 cmca and 100 cmca were 25,14% and 30,53%.

Os objetivos deste trabalho foram avaliar a influência de um composto (70% de lodo e 30% de cinza de caldeira) no desenvolvimento de árvores de Pinus taeda em locais de baixo crescimento no Brasil subtropical que apresentavam sintomas de deficiência em ciclos anteriores, e avaliar como o composto influencia as características químicas do solo. Seis meses após o transplante das mudas, foram aplicadas manualmente cinco doses do composto (controle, 14, 25, 49 e 60 Mg ha-1). Nos três anos seguintes, amostras de solo e acículas foram coletadas para análise de nutrientes, juntamente com as medidas dendrométricas das plantas. A análise do solo indicou pequeno aumento na disponibilidade de K e diminuição do Al trocável. Grandes melhorias no crescimento foram observadas em termos de altura e diâmetro na altura do peito, e a clorose da acícula desapareceu quando o composto foi aplicado. Após três anos de aplicação do composto, o volume de tronco aumentou de 13 m3 ha-1do controle para 37 m3 ha-1 no tratamento com 49 Mg ha-1. O crescimento de P. taeda foi inversamente relacionado ao Mn e diretamente relacionado à concentração foliar de K e B. Os resultados sugerem que a aplicação de composto deve ser realizada, uma vez que aumenta o crescimento inicial de P. taeda, sendo uma maneira importante de utilizar resíduos da indústria de polpa celulósica e contribuir para um manejo mais sustentável de solos de baixa fertilidade. Made available in DSpace on 2020-10-24T09:14:27Z (GMT). No. of bitstreams: 1 Maeda-2020-Anne-Pinus-residue-2318-1222-scifor-48-126-e3165-2.pdf: 1118080 bytes, checksum: 5c189146260224673e20307962d69b9b (MD5) Previous issue date: 2020

Os Neossolos Quartzarênicos são a principal classe de solos arenosos no Brasil, considerados de baixa aptidão agrícola por apresentarem baixa fertilidade natural, CTC e matéria orgânica do solo e vulnerabilidade a degradação. O uso de sistemas silvipastoris (SSPs), que se caracterizam como um tipo de sistema agroflorestal e podem ser entendidos como o processo de arborização das pastagens, são indicados para o manejo adequado desses solos. A Acacia mangium é uma leguminosa arbórea de uso múltiplo, com grande potencial para compor esses sistemas produtivos, por apresentar crescimento inicial rápido e fixar nitrogênio ao solo. Estudos de arranjos e espécies em SSP buscam identificar os efeitos sinérgicos entre os componentes, para maior diversificação das atividades de produção. Objetivou-se com este estudo avaliar as alterações nos atributos químicos de um Neossolo Quartzarênico, bem como o potencial produtivo das espécies componentes na fase de implantação de um sistema silvipastoril com Acacia mangium Willd. em diferentes arranjos e de um monocultivo de forrageiras, no Centro-Oeste Goiano. O experimento foi conduzido no município de Cachoeira de Goiás–GO, na fazenda São Miguel, em um Neossolo Quartzarênico. O delineamento experimental adotado foi o inteiramente casualizado, com parcelas subdivididas no espaço, com quatro repetições. As parcelas corresponderam a quatro arranjos espaciais: três arranjos de SSP com acácia (10×4, 15×4 e 20×4 m) e um monocultivo de gramíneas. Já as subparcelas (área de 960 m2) foram compostas por três cultivares de gramíneas: Braúna, Marandu e Massai. Os tratamentos foram implantados em dezembro de 2016. Os atributos químicos do solo foram determinados até a camada de 0,4 m, aos 10 e 20 meses após a implantação dos tratamentos. Para a determinação da produtividade de matéria seca, da composição morfológica e bromatológica das forrageiras foram realizados cortes a 20 cm de altura da superfície do solo. As avaliações do crescimento das árvores em diâmetro e altura foram feitas até os três anos de idade. Os dados foram submetidos à análise de variância a 5 e 1% de probabilidade pelo teste F e quando significativo, as médias foram comparadas pelo teste de Tukey (α = 0,05). Aos dois anos de implantação, os arranjos silvipastoris possuem uma predisposição para acidificação do solo e maior exigência em potássio em relação ao monocultivo de forrageiras, não havendo alterações significativas relevantes nos demais atributos químicos. As produtividades do componente forrageiro são semelhantes entre os arranjos espaciais, com a cultivar Massai apresentando maior potencial produtivo e baixo valor nutritivo. A Acacia mangium apresenta crescimento inicial satisfatório em sistema silvipastoril em solo arenoso, com destaque para os arranjos 10×4 e 15×4 metros, mostrando-se uma espécie apta para sistemas integrados. The Neossolos Quartzarênicos are the main class of sandy soils in Brazil, considered of low agricultural aptitude for presenting low natural fertility, CTC and soil organic matter and vulnerability to degradation. The use of silvopastoral systems (SPSs), which are characterized as a type of agroforestry system and can be understood as the process of afforestation of pastures, are indicated for the adequate management of these soils. The Acacia mangium is a tree legume of multiple use, with great potential to compose these productive systems, for presenting fast initial growth and fixing nitrogen to the soil. Studies of arrangements and species in SPS seek to identify the synergistic effects between the components, for greater diversification of production activities. The objective of this study was to evaluate changes in the chemical attributes of a Neossolo Quartzarênico, as well as the productive potential of the component species in the implementation phase of a silvopastoral system with Acacia mangium Willd. in different arrangements and a monoculture of forages, in the Midwest of Goiás. The experiment was conducted in the municipality of Cachoeira de Goiás–GO, on the São Miguel farm, in a Neossolo Quartzarênico. The experimental design adopted was completely randomized, with plots subdivided in space, with four replications. The plots corresponded to four spatial arrangements: three SPS arrangements with acácia (10×4, 15×4 and 20×4 m) and a monoculture of grasses. The subplots (area of 960 m2) were composed of three grass cultivars: Braúna, Marandu and Massai. The treatments were implemented in december 2016. The chemical attributes of the soil were determined up to the 0.4 m layer, at 10 and 20 months after the treatments were implemented. To determine dry matter productivity, morphological and bromatological composition of forages, cuts were made at 20 cm above the soil surface. Evaluations of tree growth in diameter and height were made up to three years of age. The data were subjected to analysis of variance at 5 and 1% probability by the F test and when significant, the means were compared by the Tukey test (α = 0.05). After two years of implantation, the silvopastoral arrangements have a predisposition for acidification of the soil and greater demand for potassium in relation to the monoculture of forages, with no significant applicable changes in the other chemical attributes. The yields of the forage component are similar between spatial arrangements, with the Massai cultivar showing greater productive potential and low nutritional value. The Acacia mangium shows satisfactory initial growth in silvopastoral system in sandy soil, with emphasis on the 10×4 and 15×4 meter arrangements, showing itself as a species suitable for integrated systems. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Potato (Solanum tuberosum L.) is a nutritionally demanding crop, and phosphorus (P) is a nutrient that exerts a large effect on tuber yield. However, as the availability of P is influenced by soil texture, there are doubts about how P supplementation affects the growth and yield of potato plants in different soil textures. Thus, here we aimed to evaluate the effect of P fertilization and soil texture on the nutrition, growth, tuber yield, and P use efficiency (PUE) of potato plants. The experiment was conducted under greenhouse conditions in a randomized block design with a 4×2 factorial scheme and five replications. The treatments were represented by four P rates (10, 50, 100, and 200 mg dm-3 P) and two soil textures (clayey and sandy). The concentrations of P, Ca, and Mg in the leaves were higher in sandy soil, and P rates increased the concentrations of N, P, and Ca in the leaves of potato plants. Phosphorus fertilization increased plant growth, the amount of P accumulated in the shoot, and tuber yield in both soils; this trend was stronger in the potato cultivated in the clayey soil than in the sandy soil. The applied-PUE was not affected by soil texture. In the potato cultivated in the sandy soil, the taken up-PUE was reduced due to the decrease in dry matter production and an increase in P concentration in the organs of the plant with higher P fertilizer rates. RESUMO A batata (Solanum tuberosum L.) é uma cultura nutricionalmente exigente e o fósforo (P) é um dos nutrientes que exerce grande efeito sobre a produtividade de tubérculos. Porém, como a disponibilidade de P é influenciada pela textura do solo, existem dúvidas de como o fornecimento de P afeta o crescimento e a produtividade das plantas de batata em solos de texturas diferentes. Assim, objetivou-se com esta pesquisa avaliar o efeito da adubação fosfatada e da textura do solo na nutrição, crescimento, produtividade e eficiência de uso (EU) do P das plantas de batata. O experimento foi conduzido em casa de vegetação no delineamento de blocos casualizados em esquema fatorial 4×2, com cinco repetições. Os tratamentos foram representados por quatro doses de P (10, 50, 100 e 200 mg dm-3 P) e duas texturas de solo (argiloso e arenoso). Os teores foliares de P, Ca e Mg foram maiores no solo arenoso e as doses de P aumentaram os teores de N, P e Ca nas folhas. A adubação fosfatada aumentou o crescimento das plantas, a quantidade de P acumulada na parte aérea e a produtividade de tubérculos em ambos os solos, porém, de forma mais expressiva e até maiores doses na batata cultivada no solo argiloso. A EU do P aplicado não foi afetada pela textura do solo. Na batata cultivada no solo arenoso, a EU do P absorvido foi reduzida em função da diminuição na produção de MS e aumento nos teores de P nos órgãos da planta com fornecimento de altas doses de P.