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Globally, the forestry sector is the second largest contributor of greenhouse gases, and sustainable forest management is a major target of international environmental policy. However, there is the assumption underlying many policy recommendations that an increase in above-ground carbon stocks correspond to long term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of organic inputs manipulations as part of the Detritus Input and Removal Treatment (DIRT) network. There was no statistically significant effect of the rate of litter or root inputs on the carbon or nitrogen in bulk soil, on respiration rates of soil in laboratory incubations, on the non-hydrolyzed fraction of soil organic matter, or on any organic matter associated with any density. However, there is evidence for positive priming due to increased litter inputs; doubling the rate of litter inputs decreased C and N contents of bulk soil and decreased respiration rates of soil. Furthermore, there is evidence that roots influence soil organic matter dynamics more strongly than above-ground inputs. Both of these results trends match data from other DIRT sites, and are supported by the literature. / Graduation date: 2012

Dry land agriculture using summer fallow is a common crop production practice in the Columbia Plateau region of eastern Oregon. Farmed-over level terraces are used to control surface water runoff and soil erosion. More than 70 percent of the average annual precipitation around Pendleton, Oregon (350 - 400 mm) falls as low intensity, long duration rainfall from September to March. Wetter soil zones typically occur above and below the terrace. These areas have a higher potential for crop production as well as for movement of chemicals to ground water and to surface water where seepage occurs. The extra nitrogen or water that could accumulate in these areas needs to be considered in managing these areas. The first objective of this study was to measure the distribution of nitrate nitrogen (NO���-N) and water in relation to farmed-over level terraces, and infer potential solute flow patterns from changes in the measured distributions over time. The second objective was to make recommendations regarding management practices required for specific field locations to maximize crop production and minimize negative impacts on groundwater quality. Results indicate NO������ concentrations following harvest were < 4 mg kg����� of soil. Equivalent to soil solution concentrations between 27 and 20 mg L����� at 15 and 20 percent volumetric water content, respectively. Limited deep percolation of NO������ occurred below the root zone between harvest and planting. The NO������ concentrations below the root zone were < 1 to 15 mg kg����� following the summer fallow period. In August 1993, evidence exists that shows N applied fertilizer moved out of the surface 0.3 m and deeper into the profile. The redistribution of NO������ in the terrace channels of transects 1 and 2 strongly support this. Soil profiles that contain high residual concentrations of NO���-N during the fallow period increase the potential for NO���-N leaching below the root zone. Unusually heavy precipitation during normally dry periods or above normal winter precipitation increases the potential for NO���-N leaching below the root zone. / Graduation date: 1995

The overall goal of this study was to investigate the possibility of reducing NO3-- concentration in the lower soil horizon by promoting denitrification. The study looked at an inexpensive remediation practice for subsurface-drained fields in order to degrade N0j' and consequently diminish NO3-- pollution. The experiments were conducted on a corn field at the Macdonald Campus Farm. The field was composed of sandy loam soil underlined by a clay layer. / In this study, sucrose was injected at a concentration of 20 mg L --1 within the subirrigation water. Furthermore, the water table was maintained at approximately 70 cm from the soil surface in order to create an anaerobic environment that allows for denitrification. The purpose was to furnish dissolved organic carbon (DOC) to the resident microorganisms in order to carryout a higher amount of denitrification. / The NO3-- levels in ground water were monitored weekly. Gas samples were taken from the field to observe whether N2O emissions increased as a result of the treatment This was considered to be important since N2O is a greenhouse gas. / It was found that the addition of sucrose significantly resulted in a faster rate of denitrification. The higher biological activity severely damped the NO3-- peaks in the subsoil, which arose following major rainfall events. / The addition of sucrose at 20 mg L--1 was found to be significant in lowering the amounts of released N2O. Therefore, adding DOC in the subirrigation water not only helped remediate water contamination but also served as a remedy to atmospheric pollution. / In addition, the hydraulic conductivity of the soil was monitored to ensure that no bioclogging arose from an anticipated rise in the bacterial population due to the addition of sucrose. It was found that the addition of sucrose at 20 mg L--1 did not contribute in anyway to reduce the soil's hydraulic conductivity.

This study describes a laboratory scale development of an in-situ bioremediation method, which uses a water table management system to supply nutrients to subsoil microorganisms, for biostimulation and subsequent biodegradation of pollutants such as fertilizer-nitrate and hydrocarbons (e.g., diesel oils), in the unsaturated zone of the soil. The study, which was divided into two parts: first nitrate bioremediation and secondly diesel biodegradation, was carried out on packed soil columns. / For the nitrate study, different levels of glucose were introduced into packed soil columns, 1,000 mm long x 200 mm, diameter, via subirrigation in order to supplement the organic carbon levels in the soil. Two sandy soils were used, with 1.6% and 3.4% organic matter content, respectively; and the water table in the soil columns was maintained at a depth of 350 mm below the surface. Fertilizer-nitrate was applied to the soil surface at a rate of 180 kg/ha nitrate-N. Simulated rainfall was used to leach nitrates to lower depths. The efficacy of using the subirrigation system, as a method for nutrient delivery in the bioremediation of leached nitrate, was monitored with time and with reference to the nitrate residue, redox potential of the soil solution, and solubilized Fe and Mn. / Leached nitrate was denitrified to less than 10 mg/L nitrate-N, which is the limit permitted in drinking water. The ideal organic carbon range was considered to be the glucose level (20 mg/L glucose-C) that reduced mom nitrate and gave redox potential and soluble Fe and Mn levels, similar to the control soil solution, when subjected to 96 days of subirrigation. Successful delivery of nutrient for the bioremediation of nitrate, within the farm boundaries, will be considered a "break through" toward nitrate residue control if this novel approach to nitrate control is demonstrated in the field. The delivery method will offer a technical solution to on-farm nitrate pollution. It is inexpensive, easy to adopt, and does not require major changes in the current farm practices. / In the second part of the study, a diesel contaminated sandy soil was packed in columns, 2,000 nun long x 200 nun diameter. The subirrigation method was used to supply two different combinations of treatments to the microorganisms in the soil for the biodegradation of the diesel namely: air, water and nutrients (N, P etc.), and air and water. The success of using subirrigation, to deliver nutrients to the soil in the columns, was monitored by measuring the trend in the reduction of soil diesel-TPH (diesel-total petroleum hydrocarbon) residue with time. Results obtained from the treated columns were compared with each other, and with the control columns undergoing passive biodegradation. / The study showed that subirrigation can be used as a method of nutrient delivery in the -bioremediaton of diesel contaminated soil. The TPH in the contaminated soil decreased, from an initial 670 mg diesel TPH/kg soil to an acceptable level of 40 mg diesel TPH/kg soil, in 82 days in the columns subjected to a combination of nutrient, air and water treatments. If this method of delivering biostimulants to the subsoil microbial population is demonstrated in the field, it will be invaluable to in-situ bioremediation of contaminated soils.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-07-17T12:25:34Z No. of bitstreams: 1 PDF - Carisa Rocha da Silva.pdf: 24771380 bytes, checksum: 98096514b5f8f3f27d82d7c9ab2a340d (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-07-20T12:24:03Z (GMT) No. of bitstreams: 1 PDF - Carisa Rocha da Silva.pdf: 24771380 bytes, checksum: 98096514b5f8f3f27d82d7c9ab2a340d (MD5) / Made available in DSpace on 2017-07-20T12:24:04Z (GMT). No. of bitstreams: 1 PDF - Carisa Rocha da Silva.pdf: 24771380 bytes, checksum: 98096514b5f8f3f27d82d7c9ab2a340d (MD5) Previous issue date: 2016-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The quantity and quality of food are food security and nutrition factors, ensuring health for people who consume them. Aiming to develop new options cultivation suitable for family farms was carried out this work by testing the effect of a nutrient solution for easy formulation for nutrition, production and microbiological parameters of the varieties of lettuce 'Thaís'' Vanda 'and' Veronica ', in order to identify the most adaptable to hydroponics in area Brejo Paraibano, and organo solutions, suitable for cultivation in family farming. The survey was conducted at the Center for Agricultural and Environmental Sciences (CAAC), State University of Paraíba (UEPB), adopting the experimental randomized block design in a split plot design with three replications. The plot consisted of eight nutrient solutions (one mineral - witness and seven levels of electrical conductivity variation of an organic-solution) and the subplots were arranged three varieties of lettuce. The plants were evaluated parameters of vegetative nature (number of leaves, diameter of the head lettuce and stem diameter), production (fresh and dry mass of leaves and root), nitrate levels present in plants and microbiological analysis (total coliforms and thermophilic) . In nutrient solutions and water used for irrigation of plants microbiological analyzes were performed. With the use of the physical structure of low-cost production of lettuce varieties under the nutrient solutions, evaluated the economic viability. It was found to be viable solutions for the production of hydroponic crops, especially where used irrigation water quality below the standards for vegetable production. Among the electrical conductivity of the organomineral solution, lettuce best growth was obtained with CE 1.7 and 2.1 dS m-1. Both microbiology analysis as the nitrate are indicative of consumption viability of vegetables grown under the conditions set forth in this experiment. The hydroponic lettuce, using an alternative structure and modified solutions is a profitable activity for production in family farming. / A quantidade e a qualidade dos alimentos são fatores de segurança alimentar e nutricional, garantindo saúde às pessoas que os consomem. Visando desenvolver novas opções de cultivo apropriadas para a agricultura familiar, foi realizado este trabalho, testando-se o efeito de uma solução nutritiva de fácil formulação, sobre parâmetros nutricionais, produtivos e microbiológicos das variedades de alface „Thaís‟, „Vanda‟ e „Verônica‟, com o objetivo de identificar as mais adaptáveis ao cultivo hidropônico, em área do Brejo Paraibano, e, soluções organominerais, apropriadas ao cultivo na agricultura familiar. A pesquisa foi realizada no Centro de Ciências Agrárias e Ambientais (CCAA) da Universidade Estadual da Paraíba (UEPB), adotando-se o delineamento experimental em blocos casualizados, em parcela subdividida, com três repetições. A parcela foi constituída por oito soluções nutritivas (uma mineral - testemunha e sete níveis de variação da condutividade elétrica de uma solução organomineral) e nas subparcelas foram dispostas as três variedades de alface. Nas plantas foram avaliados parâmetros de natureza vegetativa (número de folhas, diâmetro da cabeça da alface e diâmetro caulinar), produtivos (massa verde e seca de folhas e raiz), teor de nitrato presentes nas plantas e análise microbiológica (coliformes totais e termófilos). Nas soluções nutritivas e na água utilizada para irrigação das plantas foram realizadas análises microbiológicas. Com o uso da estrutura física de baixo custo e a produção das variedades de alface submetidas às soluções nutritivas, avaliou-se a viabilidade econômica. Constatou-se serem viáveis as soluções para a produção em cultivos hidropônicos, principalmente nos locais onde usada água de irrigação com qualidade inferior aos padrões para produção de hortaliças. Entre os níveis de condutividade elétrica da solução organomineral, o melhor crescimento de alface foi obtido com CE 1,7 e 2,1 dS m análises de microbiologia quanto as de nitrato são indicativas da viabilidade de consumo das -1 . Tanto as hortaliças cultivadas nas condições estabelecidas neste experimento. O cultivo hidropônico de alface, com uso de uma estrutura alternativa e soluções modificadas, é uma atividade economicamente rentável para produção na agricultura familiar.

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No description available.

A two year field study was carried out in western Quebec to investigate methods of predicting and reducing NO3--N leaching. Corn (Zea mays L.) was planted on the expel site and them were four treatments: water table controlled at 600 mm and 120 kg/ha of N fertilizer (WT120), water table controlled at 600 mm and 200 kg/ha of N fertilizer (WT200), free drainage and 120 kg/ha of N fertilizer (FD120), and free drainage and 200 kg/ha of N fertilizer (FD200). Drain flow was monitored and water samples were taken and analyzed for NO3- -N. Soil NO3- levels were measured along with led chlorophyll and denitrification throughout the two growing seasons. / Drain flow was dependent on both rainfall and the soil moisture content. In 1996, water table control decreased drain flow. However, in 1997 (a drier year), the drain flows for all treatments were similar. NO3 --N was reduced significantly in the controlled water table plots. In 1996, there was 59.2% less NO3--N in the controlled water table plots than in the free drainage plots and in 1997 this increased to 75.9% less NO3--N in the controlled water table compared to the fire drainage plots. In 1996, denitrification was enhanced by the controlled water table plots, with 72.2% more denitrification occurring in the controlled water table plots than in the free drainage plots. In 1997, there was a 93.2% increase in denitrification occurring in the water table plots than in the free drainage plots. / The controlled water table plots had no effect on plant chlorophyll levels. Chlorophyll contents of the corn plants were higher where fertilizer was applied at 200 kg/ha. Overall, it was shown that water table management can significantly decrease NO3--N pollution in drainage water. (Abstract shortened by UMI.)