Dissertations / Theses: 'Agricultural management of nutrients'

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Malone, Sarah J. "Agricultural nonpoint source pollution management : water quality impacts of Balm Road Treatment Marsh, Hillsborough County, Florida." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003211.

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HERRERA, MORENO AXEL MAURICIO. "ENVIRONMENTAL ASSESSMENT OF UNDERCURRENT AGRICULTURAL TECHNOLOGIES TOWARDS CIRCULAR NUTRIENT MANAGEMENT." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/885232.

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Circular Economy consists of re-designing effective processes that allow the subsequent recovery of wastes for new production methods, avoiding using new resources. However, an emerging holistic approach requires evidence of its systemic capacities to transition from unsustainable linear practices that had led our planet to face significant environmental problems such as climate change and alteration of biochemical flows. This study aimed to assess technologies that have proven to close C, N, and P loops regarding their overall environmental impact from two study cases; a) Microalgae production by using nutrient and water recovered streams; and b) Integrated anaerobic digestion system with precision agriculture, and bioenergy production. Results showed that the re-use of end-products is critical for positive environmental impacts due to avoided emissions from production, transport, and use of mineral sources, satisfying the aim of supporting a closed-loop integrated system. Nutrient recovery practices reduced GHG emissions, protected and enhanced soil carbon stocks, improved ground- and surface-water quality.

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Gedikoglu, Haluk McCann Laura. "Adoption of nutrient management practices." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/6614.

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Title from PDF of title page (University of Missouri--Columbia, viewed on March 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Laura McCann. Vita. Includes bibliographical references.

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Liu, Yingmei. "Effective Modeling of Nutrient Losses and Nutrient Management Practices in an Agricultural and Urbanizing Watershed." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/40398.

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The Lake Manassas Watershed is a 189 km2 basin located in the Northern Virginia suburbs of Washington, DC. Lake Manassas is a major waterbody in the watershed and serves as a drinking water source for the City of Manassas. Lake Manassas is experiencing eutrophication due to nutrient loads associated with agricultural activities and urban development in its drainage areas. Two watershed model applications using HSPF, and one receiving water quality model application using CE-QUAL-W2, were linked to simulate Lake Manassas as well as its drainage areas: the Upper Broad Run (126.21 km2) and Middle Broad Run (62.79 km2) subbasins. The calibration of the linked model was for the years 2002-05, with a validation period of 2006-07. The aspects of effective modeling of nutrient losses and nutrient management practices in the Lake Manassas watershed were investigated. The study was mainly conducted in the Upper Broad Run subbasin, which was simulated with an HSPF model. For nutrient simulation, HSPF provides two algorithms: PQUAL (simple, empirically based) and AGCHEM (detailed, process-based). This study evaluated and compared the modeling capabilities and performance of PQUAL and AGCHEM, and investigated significant inputs and parameters for their application. Integral to the study was to develop, calibrate and validate HSPF/PQUAL and HSPF/AGCHEM models in the Upper Broad Run subbasin. â One-variable-at-a-timeâ sensitivity analysis was conducted on the calibrated Upper Broad Run HSPF/PQUAL and HSPF/AGCHEM models to identify significant inputs and parameters for nutrient load generation. The sensitivity analysis results confirmed the importance of accurate meteorological inputs and flow simulation for effective nutrient modeling. OP (orthophosphate phosphorus) and NH4-N (ammonium nitrogen) loads were sensitive to PQUAL parameters describing pollutant buildup and washoff at land surface. The significant PQUAL parameter for Ox-N (oxidized nitrogen) load was groundwater nitrate concentration. For the HSPF/AGCHEM model, fertilizer application rate and time were very important for nutrient load generation. NH4-N and OP loads were sensitive to the AGCHEM parameters describing pollutant adsorption and desorption in the soil. On the other hand, plant uptake of nitrogen played an important role for Ox-N load generation. A side by side comparison was conducted on the Upper Broad Run HSPF/PQUAL and HSPF/AGCHEM models. Both PQUAL and AGCHEM provided good-to-reasonable nutrient simulation. The comparison results showed that AGCHEM performed better than PQUAL for OP simulation, but PQUAL captured temporal variations in the NH4-N and Ox-N loads better than AGCHEM. Compared to PQUAL, AGCHEM is less user-friendly, requires a lot more model input parameters and takes much more time in model development and calibration. On the other hand, use of AGCHEM affords more model capabilities, such as tracking nutrient balances and evaluating alternative nutrient management practices. This study also demonstrated the application of HSPF/AGCHEM within a linked watershed-reservoir model system in the Lake Manassas watershed. By using the outputs generated by the HSPF/AGCHEM models in the Upper Broad Run and Middle Broad Run subbasins, the Lake Manassas CE-QUAL-W2 model adequately captured water budget, temporal and spatial distribution of water quality constituents associated with summer stratification in the lake. The linked model was used to evaluate water quality benefits of implementing nutrient management plan in the watershed. The results confirmed that without the nutrient management plan OP loads would be much higher, which would lead to OP enrichment and enhanced algae growth in Lake Manassas.
Ph. D.

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Littlejohn, Alex. "Nutrient mitigation capacity of low-grade weirs in agricultural drainage ditches." Mississippi State University, 2013.

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Jakrawatana, Napat Civil &amp Environmental Engineering Faculty of Engineering UNSW. "An integrated decision support tool for more sustainable management of biomass resources in agricultural regions." Awarded By:University of New South Wales. Civil & Environmental Engineering, 2009. http://handle.unsw.edu.au/1959.4/44547.

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Agriculture currently faces a number of environmental sustainability issues. Three key issues that are the focus of this study are greenhouse gas emissions, depletion of mineral phosphorus resources and cadmium contamination in agricultural soil. Biomass can potentially be used as a renewable energy source and can also be returned to improve the nutrient and drainage structure of agricultural soils. Sustainable management of biomass and agriculture can have significant impacts on reducing greenhouse gas emissions from a region. Moreover, it reduces the demand for external energy supply, phosphorous (P) based fertilizer, and it??s associated Cadmium (Cd) impurity which can contaminate the soil, plant and food chains. These three issues have typically been considered separately, and managed by different agencies or organisations. The aim of this thesis is to develop an integrated decision support tool that can be used for evaluating alternative options for management and resource recovery from biomass for enhancing recovery of energy, returning carbon (C) and phosphorus (P) from biomass back to soil, reducing greenhouse gas emissions and also cadmium (Cd) contamination in an agricultural region. This research employed a combination of the tools of Material Flow Analysis (MFA), Geographic Information System (GIS) and Cost-Benefit Analysis (CBA). MFA is used as the primary tool for this research. GIS and CBA are combined with MFA in later stages of the overall procedure to develop an integrated decision support tool. This integrated tool has been applied to the Murrumbidgee Irrigation Area (MIA) in Australia. Tracking the flow of essential substances using MFA has identified current resource management efficiency and substances accumulation across the region. Integrating a spatial analysis tool (GIS) with MFA has provided a feedback driven monitoring tool for evaluating trends of spatial accumulation of substances on agricultural land. This enables the time remaining before acceptable limits are exceeded to be estimated on a spatial basis. Integrated MFA and CBA has been applied to evaluate the tradeoffs and potential synergies of alternative biomass management options. Overall the tool can assist in evaluating the effectiveness of alternative scenarios and visualise the results to stakeholders in a systematic way.

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Wamsley, Peter Randal. "Laboratory Analysis of Sustainable Nutrient Treatment Methods for Agricultural Runoff." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1334797563.

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Mason, Rachel. "Modeling Agricultural Outcomes in a Warmer, Wetter Vermont." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1034.

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This thesis aimed to model agricultural outcomes that are important to Vermont dairy farms and their surrounding communities -- runoff, erosion, nitrogen and phosphorus losses, crop yields, and timeliness of farm operations -- under a set of possible future climates. The Agricultural Policy/Environmental eXtender (APEX) model was used for this work, and the models were calibrated using data from a project that measured most of these outcomes on a set of local farms. The model setup and calibration methodology is thoroughly documented and may be a useful starting point for others who are new to agricultural modeling. Applied to two farms growing continuous corn, the future climate simulations showed that increasing temperatures by 2 C, combined with raising total precipitation or changing the seasonality of precipitation, had little effect on any outcome. Intense rainfall has increased greatly in recent decades, so a combination of higher temperatures and more intense precipitation was also simulated. This led to more runoff, more soil loss, and more nutrient losses. While median values were only modestly increased, the 95%-ile and total losses over the simulation period increased by a larger amount (as much as 53%, depending on the site). Management practices that can reduce runoff and soil/nutrient loss exist, but their effectiveness when a higher fraction of losses occur in large events is not well known. Crop yields changed by <10% in all simulations, and in some cases increased slightly. Other studies have warned of decreases in yields because of high summer temperatures and droughts. The pilot simulations in this thesis probed only a limited range of climate parameter space, so running the models for a wider range of scenarios may illuminate the circumstances in which particularly harmful and beneficial outcomes occur. Finally, APEX can in principle calculate the delays to corn planting that are expected if climate change leads to wetter conditions in the spring. However, the models consistently predicted that only harvest operations will be delayed. The reasons for this are not well understood, and it may be a useful avenue for future work. The present work is limited in a number of ways. Chief among these are somewhat mediocre model performance, and the narrow range of farming systems and climate scenarios investigated. Statistics describing the performance of the calibrated models were poorer than anticipated, and satisfactory results could not be obtained for some nutrient loss pathways. Only two farms were modeled, in just four hypothetical future climates; results for other relevant farming systems and climates may be quite different. Nonetheless, it is hoped that this thesis serves as a useful illustration of the potential and limitations of utilizing the APEX model in this context, and that it lays the groundwork for a more extensive investigation of agricultural outcomes under climate change in Vermont.

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Pessarakli, Mohammed, David M. Kopec, and Jeff J. Gilbert. "Growth Responses of Bermudagrass to Different Levels of Nutrients in the Culture Medium." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/216540.

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Bermudagrass (Cynodon dactylon L.), cv. Arizona Common was studied in a greenhouse to evaluate its growth responses in terms of shoot and root lengths and shoot and root dry weights under different levels of nutrients. Plants were grown hydroponically under five levels of nutrients in the growth medium [Full Nutrients (FN), Half Nutrients (½N), Quarter Nutrients (1/4N), One Eighth Nutrients (1/8N), and One Sixteenth Nutrient (1/16N)], using Hoagland solution No. 1. Plant shoots (clippings) were harvested weekly, oven dried at 60 °C, and dry weights recorded. At each harvest, both shoot and root lengths were measured and recorded. At the last harvest, plant roots were also harvested, oven dried, and dry weights were determined and recorded. The results show that shoot length, shoot and root dry weights, shoot total-N contents and concentrations, and the % of canopy green cover significantly decreased at lower (1/8 & 1/16) nutrient levels. This reduction was more pronounced as growth period progressed. Root length was stimulated at lower (1/4, 1/8, and 1/16) nutrient levels of the culture solutions. The differences in shoot lengths and shoot and root dry weights were not significant among the Full, 1/2, and 1/4 nutrient levels of the culture solutions. The differences in shoot total-N content and concentrations were not significant among the Full, 1/2, and 1/4 nutrient levels. There was no difference in either shoot total-N contents or concentrations among the respective nutrient treatments at different harvests. The above results were observed for both cumulative as well as the weekly growth responses.

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Paull, Rachel May. "Evaluating the Role of Biotic and Abiotic Ecosystem Components on the Retention and Removal of Ditch Nutrients in Ditches of Different Construction." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1594220539737151.

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Balcerzak, Ashlee Marie. "Evaluating Long-term Nutrient Impacts within Agricultural Headwater Streams." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1598021048962491.

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Hammond, Leslie. "Nutrient Availability and Dynamics of Compost Bedded Pack Dairy Barn Waste." UKnowledge, 2015. http://uknowledge.uky.edu/pss_etds/68.

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Increased adoption of compost bedded pack dairy barns (CBP), a relatively new housing and manure handling strategy, warrants study to facilitate proper use of CBP waste as a soil amendment. This study: 1) characterized in situ nutrient content and availability of CBP waste in terms of nitrogen (N) and phosphorus (P); 2) examined the decomposition of surface-applied CBP waste compared to an alternative processed solid waste amendment; 3) examined nutrient dynamics of incorporated CBP waste in high and low soil test phosphorus (STP) environments. Quick anaerobic mineralization assays revealed that bed management affects nutrient content and availability of CBP waste. A Fall surface-applied litter bag study showed that different particle sizes of CBP waste and a biosolid decomposed at similar rates. The biosolid had greater nutrient density and availability, but the decomposition was similar to CBP waste in terms of mineralization dynamics. Aerobic mineralization of CBP waste in high and low STP soils amended on a uniform P basis was compared with fresh manure. In general, CBP increased STP more and yielded more plant available P than fresh manure. These studies provide recommendations for CBP management and further study to ensure the proper land application of CBP waste.

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Armstrong, Jarrod Matthew. "Nitrogen Availability and Transport Following Drought in Three Agricultural Watersheds in Central Illinois." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1634.

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AN ABSTRACT OF THESIS Jarrod Armstrong, for the Master of Science degree in Forestry, presented on December 10, 2014, at Southern Illinois University Carbondale. Title: Nitrogen Availability and Transport Following Drought in Three Agricultural Watersheds in Central Illinois Major Professor: Dr. Karl Williard The use of inorganic nitrogen (N) fertilizers has become an essential part of modern agriculture and has helped increase yields to keep pace with an ever growing population. N is the most dynamic nutrient in nature, and biological activity can transform it into several mobile forms. Nitrate (NO3-N) is the most mobile form of N and is highly susceptible to transport to ground and surface waters. The purpose of this study was to assess N dynamics in three agricultural watersheds during and following a significant drought in 2012. Specifically, the study focuses on the mobilization and transport of residual N. The research was conducted on a ninety‐seven hectare agriculture field in Macon, County Illinois. The study site (BRKA) was divided into three watersheds, with four plots per watershed, and two topographic positions per plot. Volumetric water content (VWC) was measured continuously in each of the two topographic positions. In each watershed, stream stage collected over storm hydrographs using automated water samplers was compared to volumetric water content and NO3-N concentrations over the hydrograph. Four 6.1m groundwater monitoring wells and eight vacuum lysimeters in each watershed were monitored to determine the fate and transport of N to soil water and groundwater. Soil sampling at the 15cm depth was completed on a 0.4 hectare grid over the entire field during the fall of each year of the study. Soil and groundwater samples were analyzed monthly to compare NO3-N concentrations across topographic positions. NO3-N concentrations were highest in soil water, followed by groundwater, and lastly surface runoff. Studies in Illinois and Iowa both confirmed large amounts of residual N in the soil after the growing season in the fall of 2012 (Sawyer 2013, and Nafziger 2013). Residual N was apparent at BRKA in elevated NO3-N concentrations in soil water and groundwater after the 2012 growing season. Runoff events in April 2013 also showed increased NO3-N transport. However, due to precipitation events in the late fall and winter the residual N was flushed from the soil profile rendering it unavailable for the 2013 growing season. The soil NO3-N deficit after the 2012 drought was likely the result of decreased N fixation, N mineralization, nitrification, and leaching of any residual NO3-N. Bottomland positions consistently displayed higher soil water and groundwater NO3-N concentrations compared to uplands. However, due to a lack of plant uptake during the 2012 drought this trend was reversed and caused upland positions to exhibit higher NO3-N concentrations compared to bottomlands. This study demonstrated that even during a soybean year when no N fertilizer was applied significant drought can effectively alter the normal N dynamics at the field scale. Furthermore, this change in dynamics can lead to elevated NO3-N concentrations in soil water and ground water. These findings also suggest that precipitation events following periods of drought, like those observed after the 2012 growing season, can flush excess nutrients from the rooting zone further depleting the NO3-N pool and posing a risk to water quality. Data from a June 15, 2011 storm showed that on the falling limb of the hydrograph subsurface flow flushed soil water from the top of the slope to the bottom of the slope. This is indicative of a variable source area controlled watershed where the near stream zones undergo prolonged saturation from the subsurface drainage of the upland areas. Additionally, the early peak of NO3-N during an April 18, 2013 surface runoff event could be attributed to increased mineralization and nitrification following a rewetting of the soil profile after the 2012 drought. Lastly, topography was shown to have a strong influence on soil NO3-N concentrations across the field. This finding suggests that fertilizer applications based on topography and hydrology could help to mitigate the loss of excess NO3-N from agricultural watersheds. Furthermore, fertilizer applications should be adjusted for drought conditions that extend into the following growing season to account for residual N in the soil.

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Hedlund, Anna. "Nutrient management in smallholder peri-urban farming systems : a case study in southern Vietnam /." Uppsala : Dept. of Soil Sciences, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/9212291.pdf.

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Sisung, Theresa. "Soil testing and nutrient application practices of agricultural retailers in the Great Lakes Region." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32556.

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Master of Agribusiness
Agricultural Economics
Terry Griffin
Agricultural runoff containing phosphorus is believed to be a major contributor of algae blooms in the Western Lake Erie Basin. However, the implementation of best management practices (BMPs) can be used to help reduce the runoff of phosphorus. This research involved conducting surveys to analyze the current implementation of BMPs in Michigan and Indiana. The hypothesis is that the survey results are similar between the two states. An additional hypothesis is that the Michigan and Indiana results are similar to results from two other studies that were previously conducted. The results from this research generally support the hypothesis that a similar number of farmers in Michigan and Indiana are already implementing best management practices on their farms. In addition to the results being similar across Michigan and Indiana, there is also some evidence that shows that the results are similar to studies from the Ohio State University (LaBarge and Prochaska 2014), CropLife magazine (Erickson and Widmar 2015) and NRCS (U.S. Department of Agriculture, Natural Resources Conservation Service 2016); however upon further investigation there are distinct differences before and after media mentions of ramifications from the Lake Erie algal blooms. While it is difficult to force farmers to implement BMPs, the results of this study may help to educate them, which may cause them to add these practices to their operations.

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Henderson, Kelsey. "Reverse Osmosis as a Chemical-Free Technology for the Removal of Nutrients from Cure Meat Processing Wastewater." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563470474960378.

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Smith, Craig Matthew. "An analysis of alternative soil, nutrient, and water management strategies." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/10723.

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Doctor of Philosophy
Department of Agricultural Economics
Jeffery R. Williams
The two topics addressed in this dissertation are both related to surface water quality. Reservoir sedimentation and water quality trading are examined from economic and environmental perspectives. Each topic and the resulting policy implications are relevant to stakeholders at the local, state, and federal levels. Reservoir sedimentation has been recognized as a major environmental, social, and economic issue in much of the Midwestern US. There is an effort to focus public and private funds to achieve the greatest return on the investment from soil erosion and sediment reduction strategies. How can physiographical and economic relationships within the watershed be quantified in such a way to provide insights into the selection of alternative management strategies? This study focuses on answering that question by integrating a physically-based watershed model with an economic analysis of alternative sedimentation reduction strategies for the case of Tuttle Creek Lake located in northeastern Kansas. Several key finding of this study are that both physiographical and economic factors must be considered for cost-effective conservation to occur. Considering these factors and targeting BMP implementation from 8 to 23 times more cost-effective than random implementation. If targeting cannot be done effectively or if “intangible” costs of BMP implementation are too large, dredging is likely to be more cost-effective. While this research compares the cost-effectiveness of various BMP implementation approaches in Kansas with dredging, the benefits associated with each of these strategies is not addressed. While there is substantial evidence that nonpoint sources have lower nutrient reduction costs than point sources, experience with water quality trading (WQT) reveals a common theme: little or no trading activity. These outcomes suggest the presence of obstacles to trading that were not recognized in the design of existing programs. To examine the ways that various market imperfections may impact the performance of a WQT market, an agent-based model is constructed, which simulates a hypothetical point-nonpoint market. This study first presents an overview of the concepts and simulation modeling technique used and then analyzes the effects of two prominent market impediments identified in the WQT literature: information levels and trading ratios. The results imply that if market designers feel that only a limited number of trades will be consummated, creating an institution that provides accessible information about buyers’ prices is preferred to providing information about sellers’ prices. Overall, more information is always better, but it becomes less important with higher trading ratios.

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Nishigaki, Tomohiro. "Improvement of Water- and Nutrient-Use Efficiency with Optimum Agricultural Management Practices in Upland Cropping Systems in Morogoro, Tanzania." Kyoto University, 2017. http://hdl.handle.net/2433/228243.

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Rees, Gwendolen Jayne. "Two analyses of costs of agricultural NPS pollution: Transactions costs of expanding nutrient trading to agricultural working lands and Impacts of TCs and differential BMP adoption rates on the cost of reducing agricultural NPS pollution in Virginia." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/52939.

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For over 30 years, federal and state governments have been engaged in a collective effort to improve the water quality and living resources in the Chesapeake Bay (CB), focusing particularly on reducing delivered nitrogen and phosphorus loads. However, achievement of water quality objectives remains elusive. In Virginia, agriculture represents the single largest source of nutrient loads to the Chesapeake Bay. Despite aggressive regulatory efforts in other nutrient source sectors, state authorities rely on educational programs and voluntary financial assistance programs to induce landowners to adopt best management practices (BMPs) that reduce agricultural nutrient loads. This study explores two economic aspects of efforts to reduce agricultural nonpoint source (NPS) pollution in the Virginia portion of the CB watershed. Firstly, current and possible future transactions costs associated with specific aspects of agricultural NPS participation in water quality trading (WQT) programs are examined in Chapter 1. A case study approach is used to consider the possible cost consequences of expanding the use of NPS credits from agricultural 'working lands' BMPs in Virginia. Findings indicate that overall transactions costs for nutrient trades involving agricultural NPS in Virginia are currently relatively low, due to the type of activities being credited: simple land conversions. Based on best available evidence, the administrative transactions costs of creating credits on agricultural 'working lands' using management and structural BMPs will be 2 to 5 times more costly on a per project basis than for credits generated from land conversions. Compliance monitoring protocols were found to be a significant driver of costs for credits generated from working agricultural lands. These results suggest an important cost/risk tradeoff between verification cost and compliance certainty for program designers to consider. The second study (Chapter 2) considers the economic cost of meeting pollution reduction targets for the Virginia portion of the CB Watershed. Existing cost models are based on simplifying behavioral assumptions about public transactions costs, conservation adoption rates, and implementation costs of agricultural BMPs. This study builds on the existing literature and uses the estimates of transactions costs from Chapter 1 together with information on producer BMP adoption rates to examine the implications of including transactions costs and differential BMP costs and adoption rates when estimating the minimum costs of achieving specified nutrient reduction goals in Virginia. The paper uses a cost-minimizing mathematical programming approach and models a number of different cost scenarios. Results indicate that inclusion of transactions costs substantially affects estimates of total costs of meeting nutrient reduction goals; on average total costs increased by 44 percent, but ranged between 19 and 81 percent depending on the scenario analyzed. Analysis of the modelled scenarios shows that those BMPs that account for the most implementation costs do not necessarily account for the most transactions costs (and vice versa). This suggests that transactions costs should be acknowledged to vary with the type of practices being implemented, rather than being approximated as either a fixed amount or a fixed proportion of implementation costs. In addition, the analysis highlights the disproportionate costs associated with achieving nutrient reductions via high-cost adopters, and suggests there may be a role for education or extension to assist landholders to lower opportunity costs of participating in conservation.
Master of Science

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Spangler, Jonathan Travis. "An Assessment of Floating Treatment Wetlands for Reducing Nutrient Loads from Agricultural Runoff in Coastal Virginia." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/86656.

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Floating treatment wetlands (FTWs) are an innovative best management practice that can enhance the performance of traditional retention ponds by increasing removal of the nutrients nitrogen (N) and phosphorous (P). FTWs consist of floating rafts on which wetland plants are planted, allowing the roots to be submerged below the water surface while the shoots remain above. A growing body of research has documented FTW performance with regard to urban runoff treatment, however evaluation of FTW effectiveness for treatment of agricultural runoff has received less attention. Due to high fertilization and irrigation rates, commercial nursery runoff contains much higher concentrations of N and P than runoff from urban areas. We conducted this study over two growing seasons (2015 and 2016) to assess the effectiveness of FTWs for use in commercial nursery retention ponds. In the first study we used two different nutrient concentrations, one to simulate nursery runoff (17.1 mg∙L-1 TN and 2.61 mg∙L-1 TP) and one to simulate concentrations that fall between urban and nursery runoff (5.22 mg∙L-1 TN and 0.52 mg∙L-1 TP). Four treatments were used: 1) Pontederia cordata planted in cups supported by a Beemat, 2) Juncus effusus planted in cups supported by a Beemat, 3) a Beemat with no plants, and 4) no treatment (open-water). Performance was evaluated based on a 7-day hydraulic retention time (HRT). Pontederia cordata removed between 90.3% and 92.4% of total phosphorus (TP) and 84.3% and 88.9% total nitrogen (TN), depending on initial loads. These reductions were significantly more than other treatments at both high and low nutrient loading rates. Juncus effusus performed better than the control treatments for TP removal at low nutrient concentrations, but did not perform any better than the control at higher nutrient loads. In the second study, conducted in 2016, we evaluated different plant species over two 8-week trials using simulated nursery runoff. We used five monoculture FTWs with the following species: Agrostis alba, Canna ×generalis, Carex stricta, Iris ensata, and Panicum virgatum. Additionally, two treatments were created from mixed species plantings and the final treatment consisted of an open water control mesocosm. Nutrient removal performance was evaluated over a 7-day HRT. P removal (phosphate-P) by FTW treatments ranged from 26.1% to 64.7% for trial 1 and 26.8% to 63.2% for trial 2. Trial 1 N removal (sum of ammonium-N, nitrate-N, and nitrite-N) efficiencies ranged from 38.9% to 82.4%, and trial 2 ranged from 12.9% to 59.6%. Panicum virgatum removed significantly more N and P than the control and any other FTW treatment in the second study. Both studies indicated, depending upon plant species, that FTWs can effectively remove nitrogen and phosphorous from urban and commercial nursery retention ponds.
Master of Science

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Cowan, Watts Cara Ailene. "Critical review of us environmental protection agency numerical nutrient criteria with respect to culturally significant waters as a designated use." Thesis, Oklahoma State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163015.

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The Cherokee Nation, a Federally-recognized Tribal government in Northeastern Oklahoma lacks Tribal water quality standards for numerical nutrient standards based on baseline conditions in the Cherokee Nation. Lotic waters are of special significance in Cherokee Nation culture and ceremonies. Three water quality standard priorities within the Tribe include defining Culturally Significant Waters as a designated use, identifying Culturally Significant Waterbodies and determining applicable numerical nutrient standards. Culturally Significant Water as a designated use was defined based on community surveys. Twelve rivers and streams were identified as a portion of the Culturally Significant Waters of the Cherokee Nation based on a tribal community survey using a Use Attainability Analysis. To address excess nutrients in the Cherokee Nation, a total phosphorus numerical nutrient criterion was determined using data for Culturally Significant Water bodies, literature guidance and the US Environmental Protection Agency recommended nutrient criteria process for the respective Aggregate Nutrient Ecoregion. The Oklahoma Scenic Rivers criterion of 0.037 mg/L total phosphorus for a 90-day geometric mean was evaluated and determined not to be protective of Cherokee Nation’s Culturally Significant Waters. A total phosphorus criterion of 0.016 mg/L was recommended to protect Cherokee Nation Culturally Significant Waters from benthic algae greater than 100 mg/m² Chlorophyll a.

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Saltos, Theodore Nicholas. "Assessment of Agricultural Nutrient Pollution to Lake Erie from the Maumee and Sandusky Watersheds: Analyzing Trends in Hydrology, Nutrient Loading, and Policy Using a Statistical Approach." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531928517302473.

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Wang, Lei. "Developing an integrated catchment-scale modelling approach for supporting the sustainable management of water nutrient pollution from diffuse agricultural sources." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54893/.

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Water is one of our most vital natural resources for life sustaining and human's economic development and social well-being. Agricultural diffuse water pollution (ADWP), the biggest remaining problem of water pollution in the world, has been realised as a major threat for water quality and the implementation of the EU Water Framework Directive (WFD). Indicative estimates of the costs of water pollution from ADWP are about £225 M per year in the UK, whilst failure to meet the requirements of the EU WFD by 2015 may incur heavy fines. From the technical and scientific points of view, there are three major gaps, namely, "method and tool", "research scale" and "fundamental knowledge" gaps between current ADWP research and the successful implementation of the EU WFD. It is timely to develop integrated catchment-scale numerical modelling tools or methods to handle the ADWP problem at the catchment scale. This thesis describes the development of an integrated catchment-scale modelling approach, ICEMAN, for supporting the effective decision-making of the ADWP sustainable management at the catchment scale, thus helping the implementation of the EU WFD in handling ADWP. In order to quantitatively describe the nutrient process in the complete hydrological cycle, it is necessary to integrate numerical water models into ICEMAN to calculate or simulate the groundwater pollution pathway vulnerability, groundwater pollution risk, water balance in soil, nutrients biochemical cycling in soil, and surface water quality and quantity processes. This study showed that GIS and the Arc Hydro model consisting of the modules of data mining, hydrological analysis, and visualisation can facilitate the developing and applying the ICEMAN by providing data support and powerful functions of spatial analysis. The DRASTIC model was applied in the case study area - Upper Bann Catchment, Northern Ireland for assessing the groundwater pollution pathway vulnerability of general pollutants and pesticide. The results showed that DRASTIC is suitable to be introduced into the ICEMAN for catchment-scale groundwater pollution vulnerability assessment. However, DRASTIC has drawbacks in the groundwater pollution risk assessment, namely, having no risk concept and considering no pollutant dynamic nature with runoff. A D-DRASTIC approach was developed in this study for reliable groundwater pollution risk assessment from diffuse agricultural sources based on DRASTIC within an ArcGIS environment. D-DRASTIC overcomes the pitfalls of applying DRASTIC in groundwater risk assessment. The results of applying D-DRASTIC in the case study showed that D-DRASTIC is helpful in guiding the activities of groundwater pollution prevention at the catchment scale and can be used in the development of ICEMAN. A numerical catchment-scale surface water model capable of the simulation of ADWP is necessary in developing the ICEMAN method. A HSPF model was selected based on the review of popular surface water models and tested in the study area. The calibrated and validated HSPF model can well represent the characteristics of surface water quantity and quality in the study area. Climate change scenario evaluation results in five years showed that when the annual mean temperature increase 3 Celsius the mean yearly total runoff volume will decrease by 11% and the mean daily river flow of five years will decrease by 11%. The results showed that HSPF is a suitable model in simulating the diffuse source surface water pollution and can be integrated into the ICEMAN. ICEMAN was developed by integrating the models of Arc Hydro, DRASTIC, D-DRASTIC, HSPF into an ArcGIS environment. ICEMAN can describe the nutrient biochemical cycles in soil, whole hydrological quantity and quality processes, and groundwater pollution vulnerability and risk, by considering factors in the catchment ADWP process, namely, meteorology, nutrient loading from different land uses, nutrient biochemical cycling in soil, nutrient dynamic nature with runoff and interflow, topography, depth to water, net recharge, aquifer media, soil media, impact of the vadose zone media, hydraulic conductivity of the aquifer, and the relationships between soil water and groundwater. The results of applying ICEMAN in the study area showed that ICEMAN can well support the decision-making of the catchment ADWP sustainable management. In the study area, ICEMAN provides satisfied simulation of river flow and quality, groundwater pollution vulnerability and risk zones, and quantitative descriptions of ADWP process including nutrient biochemical cycle in soil and can help better understand the ADWP characteristics in a specific catchment. In addition, ICEMAN can evaluate the impacts of water management plans on water processes under the climate change. For example, when changing 20% farming land into forest land in the Gamble's Bridge watershed of the study area, the mean concentrations of nitrate, nitrite, NH4, and P04 in river will decrease by 19%, 33%, 31%, and 31% respectively. ICEMAN, transferable to other areas, can bridge gaps of "method and tool" and "research scale" in the implementation the EU WFD in handling ADWP and can act as an important complement of the River Basin Management Plans. This multi-disciplinary study may provide a good starting point for tackling ADWP at the catchment scale in an integrated, quantitative, and sustainable manner. Therefore, the results in this multi-disciplinary study are not only useful for better implementation of the EU WFD, but also helpful for tackling the ADWP problem outside the EU.

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Twombly, Cameron Robert. "Edge-of-Field Hydrology and Nutrient Fluxes within Northeastern Agroecosystems: Evaluation of Alternative Management Practices and Water Quality Models." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1170.

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Agricultural runoff is one of largest contributors of phosphorus (P), nitrogen (N), and sediment affecting freshwater systems in watersheds across the Northeastern U.S., including the Lake Champlain Basin in Vermont. Agricultural cropping systems, such as corn silage and haylands, used for dairy feed production have been shown to impact watershed hydrology and water quality. Agricultural best management practices (BMPs) have the potential to decrease runoff volumes and flow rates and the associated export of nutrients and sediment from agricultural fields. Many states in the Northeastern U.S., including Vermont, are beginning to require farmers to implement water quality BMPs and further improve risk evaluation of export of P in runoff using evolving P site assessment tools, such as the Phosphorus Index (P-Index). Quantifying the effects of BMPs on hydrologic and nutrient exports from fields is critical for informing site assessment tools that aid in the development of nutrient management plans and to help design agroecosystems that do not degrade water quality. However, there is a lack of data on the effects of BMPs on edge-of-field hydrologic and nutrient fluxes, especially in cold-climate regions with snow-melt induced runoff events. This thesis consists of four chapters, Chapter 1 is a comprehensive literature review on agricultural hydrology and water quality, BMP effectiveness, and P site assessment tools. Chapters 2 and 3 address research objectives related to the evaluation of BMP and P site assessment tool effectiveness. Chapter 4 is a summary of the conclusions drawn from the work done in Chapters 2 and 3, and suggestions for future work. Chapter 2 evaluates the effects of soil aeration prior to manure application on edge-of-field hydrology, water quality, and P fluxes in haylands with clay soils during both precipitation and snow-melt induced runoff events. Edge-of-field water quality monitoring techniques and passive-capillary lysimeter systems were used to continuously measure the losses of surface runoff, subsurface leachate, and the associated export of nutrients (total phosphorus, total dissolved phosphorus, total nitrogen, and total dissolved nitrogen) and total suspended solids resulting from runoff events year-round from 2012 to 2018. Annual P fluxes in the form of vegetative uptake and removal, manure additions, and soil test P were also recorded. Results from this study indicated that soil aeration had the potential to reduce nutrient and sediment exports from haylands with poorly-drained, high runoff producing soils in the Northeastern U.S. where winter freeze-thaw conditions exist. However, potential increases in surface and subsurface hydrologic flows can accompany these reductions; these implications should be considered before implementation. Chapter 3 identifies potential P-Index improvements through the representation of topographic controls on phosphorus (P) transport by comparing results from the Vermont P-Index (VT P-Index) and a more complex process-based model, TopoSWAT, across topographic regions in a small agricultural watershed (360 ha) in the Lake Champlain Basin. Scenarios of varying P management strategies were modeled for corn silage production fields with poorly-drained soils and rolling topography. Modeled outputs of P risk assessments and edge-of-field dissolved and particulate P losses were compared. Results from this study suggest that the VT P-Index could improve its ability to support farm nutrient management planning and other P-based management decisions by incorporating topographic controls of runoff production into its estimation of P transport.

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Ageson, Karen. "Agricultural nutrient management employing the concept of ecological goods and services : a valuation of ground water quality in Abbotsford, British Columbia." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/38630.

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There is an appetite for market based management mechanisms in agri-environmental policy. The purpose of this study is to explore how the market based concept of ecological goods and services (EGS) can be applied towards the management of an agricultural externality in British Columbia, Canada. Through literature review I establish the importance of valuation in market based management. With an EGS program in mind I identify the City of Abbotsford as a potential ecological service buyer and establish economic value for improvements to water quality in the Abbotsford-Sumas aquifer. I use a replacement cost approach based on the present value costs of the proposed Stave Lake surface water system. My results suggest that if nitrate remediation and/ or nitrate management practices improve water quality and the costs fall below $168 million there are potential net benefits to the City of Abbotsford. This value could form the basis for a city program or EGS trading scheme to encourage farmers to place a higher priority on water quality in their land management practices. A key finding is that lack of information on the degree to which nitrate contamination constrains well field development limits the ability to conclusively evaluate the net benefits of improved nitrate management and proceed with an EGS program.

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Schaible, Candace J. "Assessing Homeowners' Lawn Management Practices and Preferred Sources of Educational Information." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7041.

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Prior to the development of programing and outreach materials it is important for Extension outreach and education professionals to assess the educational needs and preference of the communities they serve. Survey data was gathered from residents of Cedar City, UT, in an effort to gain an understanding of current lawn management practices and the resources homeowners utilize when making management decisions. In addition, soil samples were collected from a subset of participants to compare nutrient levels to management practices. Survey results found that homeowners accessed multiple sources, with preferences leaning towards the use of friends and family members, the internet, and the point of purchase. Few homeowners are aware of and utilize educational resources and services provided by Extension. This is especially true for those under the age of 50, which poses a challenge to Extension professionals to find effective ways to reach younger generations. It was difficult to form associations between nutrient levels and management practices Although, there was a strong association between those with excessive phosphorus concentration and the application of biosolids. More research needs to be done to examine the distribution and end use of biosolids.

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Gildow, Marie C. "Evaluating Fertilizer Application Practices to Reduce Phosphorus Discharge from the Maumee River." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437400849.

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Vargas, Filipe Marcel da Rosa. "Deposição de serrapilheira e ciclagem de nutrientes em Pinus taeda L. em sistema silvipastoril." Universidade Tecnológica Federal do Paraná, 2011. http://repositorio.utfpr.edu.br/jspui/handle/1/455.

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Este trabalho teve como objetivo, estudar a ciclagem de nutrientes via serrapilheira em plantios de Pinus taeda em sistema silvipastoril, através da quantificação do aporte de serrapilheira, da velocidade de decomposição desta e do retorno de nutrientes (N, P, K, Ca e Mg), em função do espaçamento e da posição de amostragem. A deposição de serrapilheira na densidade de plantio florestal convencional é maior em relação a baixas densidades de plantio, utilizadas em sistemas integrados de produção. Muito embora a deposição unitária seja menor, quanto maior for a densidade do plantio. O período do ano em que houve maiores deposições de serrapilheira foi o mês de abril, com exceção da linha de plantio na densidade de 1.111 árv. ha-1, que foi no mês de maio. Houve interação entre densidade de plantio, distância da linha de plantio e período para a liberação de todos os macronutrientes no sistema, bem como para a relação C/N.
This work aimed to study the cycling of nutrients via litterfall in Pinus taeda in silvopastoral system, by quantifying the contribution of litter, the decomposition rate and this the return of nutrients (N, P, K, Ca and Mg ) as a function of spacing and sampling position. The deposition of litter in conventional forest planting density is higher than at low planting densities, used in integrated production systems. Although the deposition unit is smaller, the greater the density of planting. The period of the year in which there was greater deposition of leaf litter was the month of April, with the exception of the plant row at a density of 1,111 trees ha-1, which was in May. There was an interaction between plant density, distance from the plant line and time for the release of all macronutrients in the system, as well as for the C / N.

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OLIVEIRA, David Castor Maxwel. "Avalia??o de um sistema agroflorestal com a?a?, mogno africano e leguminosas arb?reas implantado h? 10 anos em Serop?dica, RJ." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1835.

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Agroforestry systems (ASF) are potentially characterized as a agroecological crops by the similarity to the forest structure and function which gives more sustainability to the production systems, making them environmentally friendly. This study evaluated an AFS ten years plantation to obtain information about the nitrogen fixing legumes influenced over the soil chemical properties, the palm heart production, the Khaya ivorensis A. Chevalier and Euterpe oleracea Mart. Growth, and finally the common beans cultivation. The AFS was located at Embrapa Agrobiologia Experimental field, at Serop?dica city, Rio de Janeiro state. The statistical was randomized blocks with 5 treatments and 4 replications with 9 m x 9 m plots and total area with 1.620 m2. There were E. oleraceae, planted in a 3 m x 3 m spacing with one plant of K. ivorensis at the plot center. The treatments were different kinds of green manure crops between the lines such as: Acacia angustissima (Mill.) Kuntze; Gliricidia sepium (Jacq.) Steud;. Canavalia ensiformis (L.) DC, nitrogen fertilization with castor cake and spontaneous vegetation. For the soil fertility analyses were collected two samples, one before and other after green manure crops management. K. ivorensis and E. oleraceae biometry, also heart palm production were harmed by inappropriate management on cultivation care lack between post planting and this evaluation lapse. These commercial crops reached larger diameters and superior height at the plot without leguminous crops competition. Green manure crops were efficient in soils nutrients cycling, increasing the most elements content after pruning the leguminous plants and the application of the biomass over the ground. Extract nodules inoculation showed capacity to increase nodulation and nitrogen content in common beans plants, but didn?t increase the grain production.
Os sistemas agroflorestais (SAF) podem ser configurados como cultivos agroecol?gicos, onde a similaridade com as florestas em estrutura e fun??o confere ao sistema uma maior sustentabilidade, tornando-os ambientalmente adequados. Este estudo avaliou um SAF com 10 anos de implanta??o, gerando informa??es sobre quanto as culturas de leguminosas fixadoras de nitrog?nio influenciaram nas propriedades qu?micas do solo e na produ??o do sistema, quantificando a produ??o de palmito, o crescimento de plantas de Khaya ivorensis A. Chevalier e Euterpe oleracea Mart. plantados e o cultivo de feij?o. O experimento estava localizado no Campo Experimental da Embrapa Agrobiologia, no munic?pio de Serop?dica, do Rio de Janeiro. O delineamento experimental adotado foi o de blocos ao acaso com cinco tratamentos e quatro repeti??es, com parcelas de 9 m x 9 m cada, totalizando 1.620 m2. Em todos os tratamentos existiam a?a?s plantados de 3 m x 3 m ao longo de todas as parcelas que tamb?m continham um mogno africano no centro de cada uma. Os tratamentos foram compostos por aduba??es verdes nas entrelinhas dos a?a?s, constitu?dos por Acacia angustissima (Mill.) Kuntze; Gliricidia sepium (Jacq.) Steud.; p aduba??o nitrogenada de cobertura com torta de mamona e o controle com vegeta??o espont?nea. Para avalia??o qu?mica do solo foram feitas duas coletas, uma antes e outra p?s manejo da biomassa vegetal. Foi realizada a biometria das plantas de mogno africano, de a?a?, e a quantifica??o da produ??o de palmito, onde foi poss?vel perceber que essas culturas tiveram o crescimento prejudicado devido a falta de manejo, tendo em vista que houve menos competi??o nas parcelas sem leguminosas arb?reas, onde essas culturas de interesse atingiram maiores di?metros e alturas, refletindo da mesma forma na produ??o de palmito. A aduba??o verde foi eficiente na ciclagem de nutrientes do solo, aumentando o teor da maioria dos elementos ap?s um manejo e superando vegeta??o espont?nea al?m de ter beneficiado a produ??o do feijoeiro. A inocula??o com extrato de n?dulos ? capaz de aumentar a nodula??o e o teor de nitrog?nio da parte a?rea do feijoeiro, por?m n?o aumentou a produ??o de gr?os.

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Miller, Kayla Marie. "Vegetating Shallow Field Ditches in the Paulding Plains of the Western Lake Erie Basin for Improved Water Quality." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483622025510358.

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31

Norton, Elbert Randall. "Nutrient and crop management studies in irrigated cotton production systems." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/279773.

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Increased efficiency in agricultural production is becoming increasingly important in the present economic climate. The three studies presented in this dissertation have been developed to help producers achieve a greater efficiency with respect to crop production. The first is the development of the cotton monitoring system (CMS). This software was developed as an end product to over ten years of research into cotton crop monitoring. It allows for the entry of crop growth and development data, along with other crop inputs. All growth indices are plotted against long-term baselines to indicate the crops status in relation to normal growth patterns. Other University of Arizona extension publications are available that are directed at helping the user interpret the data and how best to use it in making management decisions. The second project involves the evaluation of added nitrogen interaction (ANI) effects in irrigated cotton. This was accomplished by comparing two methods of determining nitrogen recovery efficiencies (NREs), the difference technique and the isotopic dilution technique. No differences were observed between the two methods in the first year, 1997 indicating the absence of a ANI. However in 1999, differences were observed between the two methods due to abnormally high vegetative growth experienced by the crop which resulted in increased root growth and subsequent exploration of the soil and an increased uptake of soil N. The third and final project was conducted to examine the loss of N from several different sources of irrigation water around the state of Arizona and to observe the effects of temperature on this process (25, 30, 35, and 40°C). Ammonium sulfate was added to a 350 mL volume of water from which aliquots were drawn at specific time intervals and analyzed for NH₄⁺-N. In a 24 hour period up to 90% of the added N was lost at 40°C). In general, as soluble salts increased the rate at which NH3 was volatilized also increased. The results from this study indicate the need to consider potential N losses from irrigation water when making decisions regarding N fertilizer management.

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Fischer, Peter. "The degree of phosphorus saturation of agricultural soils in Brazil and Germany: New approaches for risk assessment of diffuse phosphorus losses and soil phosphorus management." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19589.

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Diffuse Phosphor (P)-Austräge aus der Landwirtschaft tragen zur Gewässereutrophierung bei. Der Phosphorsättigungsgrad (DPS) ist ein etablierter Parameter, um das P-Austragsrisiko aus Böden zu erfassen. Ein bodentypunabhängiger Ansatz, der die Abschätzung des DPS durch eine einfache Standardmethode wasserlöslichen P (WSP) ermöglicht (WSP-DPS-Ansatz), wurde an europäischen Böden entwickelt. In der Dissertation wurde dieser Ansatz erstmalig: i) an tropischen Böden getestet und ii) dazu verwendet P-Austragsrisiken von Boden-P-Monitoringdaten und von landwirtschaftlichen Institutionen empfohlenen P-Gehalten abzuleiten. Neben dem DPS wurde der Einfluss der in Brasilien gängigen anorganischen Oberflächendüngung auf das Austragsrisiko mittels Laboranalysen und Feldstudien erfasst. Die Bodentypunabhängigkeit des WSP-DPS-Ansatzes wurde für Böden Brasiliens bestätigt. Infrarotspektroskopische Analysen lieferten eine Erklärung für relativ niedrige gelöste P-Konzentrationen im Oberflächenabfluss von Oxisols. Pedotransferfunktionen zwischen WSP und Methoden, die in Brasilien und Deutschland zur Abschätzung pflanzenverfügbaren P verwendet werden, ermöglichten die Berechnung von DPS-Werten aus Monitoringdaten. Erste DPS-Karten zeigten relative geringe Austragsrisiken für das Untersuchungsgebiet in Brasilien und hohe Risiken für Deutschland, die teilweise durch unterschiedliche empfohlene Boden-P-Gehalte erklärbar waren. Um mit einer einfachen und kosteneffizienten Methode sowohl die landwirtschaftliche Produktion als auch den Gewässerschutz zu berücksichtigen, wurden die Wasser- und CaCl2-Methode zur Abschätzung von pflanzenverfügbarem P mit dem WSP-DPS-Ansatz kombiniert. Dieser Ansatz könnte helfen die Herausforderungen zu lösen mit denen die Menschheit in den nächsten Jahrzehnten bezüglich P in der Landwirtschaft konfrontiert sein wird: Einer effizienten Nutzung der limitierten Ressource P und dem Schutz der Gewässer vor diffusen P-Einträgen.
Diffuse phosphorus (P) losses from agriculture contribute to the eutrophication of surface waters. The degree of P saturation (DPS) is an established parameter for assessing the risk of P loss from agricultural soils. A soil type-independent approach for estimating the DPS by a simple standard method of water-soluble phosphorus (WSP; the WSP-DPS approach) was developed on European soils. In the thesis, the WSP-DPS approach was for the first time: i) tested on tropical soils and ii) used to derive P loss risks from soil P monitoring data and from recommended soil P levels by agricultural institutions. In addition to DPS, laboratory analyses and field studies were combined to assess the risk of P loss associated with the superficial application of inorganic fertilizer, which is commonly used in Brazil. The soil type-independency of the WSP-DPS approach was confirmed for soils of Brazil. Infrared spectroscopic analyses provided an explanation for the relatively low dissolved P concentrations in the surface runoff of Oxisols. Pedotransfer functions were determined between WSP and methods used to estimate plant-available P in Brazil and Germany and allowed for the transformation of soil P monitoring data into DPS values. The first DPS maps revealed relatively low P loss risks for the investigation area in Brazil and high risks for Germany. This difference was partly explainable by the recommended soil P levels in the two countries. To consider both agricultural production and the protection of surface waters in soil P management with a simple and cost-effective method, the soil test methods of using water and CaCl2 to estimate plant-available P and the WSP-DPS approach were combined. This approach could help to solve the challenges humanity faces regarding P in agriculture in the coming decades: An efficient use of the limited resource P and the protection of surface waters from diffuse P losses.

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Avila, João Eduardo Tombi de. "Caminhos para a transição agroecológica : estudo com uma família do assentamento Fazenda Ipanema, Iperó (SP)." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/130.

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Many farmers consider Agroecology a tool to produce sustainably. By changing their production systems, changing crops and inputs applied, aiming at a sustainable system, the family farmer search a transition agroecology. However, few among them can produce or advance in agroecological transition. A reason for this difficulty may be related to biomass production in quantity and quality to ensure the agroecosystems sustainability. The family agroecosystems tend to have greater biodiversity than large farms due to a tendency to polycultures, self, family pluriactivity, among other strategies. In this local biodiversity, plants play a key role and can be considered co-products. This study aimed to characterize a unit of production and family life (UPVF) adopting management practices aimed at agroecological transition, to discuss the importance of plant biomass in this transition process and to propose alternatives to achieve the fertility system. The research was developed at Iperó in Ipanema Farm settlement in the State of Sao Paulo. The UPVF studied occupies a plot of eight hectares and is divided into seven sectors of production. The family with whom this work was developed live in the settlement since 1992. The research aimed to detail the system features and the complexity of relationships in order to describe and analyze a case study setting. It was found that the biomass produced in UPVF did not meet the nutritional demand of the main sector of commercial product, the banana orchard. The proposed redesign sought to ally virtuous experiences and scenic beauty, attractive for humans. Thus, the UPVF redesign aimed at promoting the cradle areas of fertility, assisted in the production of plant biomass in abundance and quality (diversity), preferably in well accessible, as the surrounding residences, places of daily traffic and nearby areas containment of animals. Thus, it is expected to 16 contribute to the sense of pride in the family for the successful transformation of the local landscape and the awareness of what it represents.
Muitos agricultores familiares consideram a Agroecologia a base para se produzir de forma sustentável. Com base nos princípios agroecológicos, alguns deles alteram seus sistemas produtivos, modificam os cultivos e os insumos aplicados. Entretanto, poucos conseguem produzir ou avançar no sentido de obter uma produção sustentável, em termos ambientais e econômicos. Entre os possíveis fatores que dificultam essa transição agroecológica constata-se a dificuldade para produzir biomassa em quantidade e qualidade que garanta a sustentabilidade desses agroecossistemas. Os agroecossistemas familiares tendem a apresentar maior biodiversidade em relação às grandes propriedades rurais em função da tendência aos policultivos, autoconsumo, pluriatividade familiar, entre outras estratégias. Dentro dessa biodiversidade local, os vegetais desempenham um papel fundamental e podem ser considerados coprodutos da unidade produtiva. Esta pesquisa teve por objetivos caracterizar uma unidade de produção e vida familiar (UPVF) que adota práticas de manejo visando a transição agroecológica e propor alternativas de manejo para aumentar a produção de biomassa vegetal nesse processo de transição. A pesquisa se desenvolveu em Iperó, no assentamento Fazenda Ipanema, no Estado de São Paulo. A UPVF estudada ocupa um lote de oito hectares e está dividida em sete setores de produção. A família com quem se desenvolveu este trabalho vive no assentamento desde 1992. A pesquisa buscou detalhar as especificidades do sistema e a complexidade das relações, de forma a descrever e analisar a UPVF escolhida, estabelecendo um estudo de caso. Constatou-se que a biomassa produzida na UPVF não atendeu à demanda nutricional do principal setor de produção comercial do lote, o pomar de bananeiras. O redesenho proposto buscou aliar experiências bem sucedidas e beleza paisagística, um 14 atrativo para os seres humanos. Assim, o redesenho da UPVF teve por meta favorecer as áreas berço de fertilidade, apoiadas na produção de biomassa vegetal em abundância e qualidade (diversidade), de preferência, em locais bem acessíveis, como o entorno das residências, locais de trânsito diário e proximidades das áreas de confinamento dos animais. Dessa forma, espera-se contribuir para o sentimento de orgulho na família pelo êxito na transformação da paisagem local e a consciência do que ela representa.

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Lister, James Edward. "The behaviour of plant nutrients in colliery spoil of Central Scotland." Thesis, University of Glasgow, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335480.

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Sarikaya, Ebru. "Agricultural Reuse Of Water And Nutrients From Wastewater Treatment In Izmir Region." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614337/index.pdf.

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Rapid urbanization and population growth have represented a great challenge to water resources management, since wastewater generated in urban areas forms a non-conventional source, wastewater reuse is being recognized as a sustainable water management approach. This study focuses on with the potential and practibility of implementing wastewater reuse techniques in Izmir region, especially with the aim to use treated wastewater and nutrient for agriculture. To this end, qualititative and quantitative agricultural water demand were considered. This thesis introduces a wastewater reuse planning model and optimization method with an emphasis on the wastewater treatment technology used as well as the agricultural demand in the area of the study. The model was developed with considerations over water quality, wastewater treatment and discharge. The objective of the model is to upgrade existing wastewater treatment plants or to design new treatment plants in regard to reuse wastewater in agriculture. The model is also capable of comparing treatment technologies from the point of design and cost. Three case studies were represented so as to demonstrate the modeling process and optimization studies for agricultural irrigation.

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King, Ben Peter. "Identification and quantification of medium-term sediment storage within agricultural catchments." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312286.

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DePrator, Francesca Victoria. "Innovation Among Nutrient Service Providers in the Midwest." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1525717706908821.

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Walworth, James, and David M. Kopec. "Aquatrols Surfactant Study on Turfgrass Nutrient Uptake." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/216541.

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Farthing, Tessa. "Impact of a Forested State Park on Nutrient Concentrations in an Agriculturally Dominated Watershed in Southwest Ohio." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626999681372348.

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Mehramiz, Mohammad Reza. "Nutrient contents of three Atriplex species (Atriplex cancensces, atriplex linearis and Atriplex polycarpa) under different management practices and site conditions." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282667.

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There are thousands hectares of abandoned farmlands in Arizona. Research on practical methods for establishing native plants and wildlife on abandoned farmlands is under way at the Desert Botanical Garden of Phoenix and the University of Arizona. This research is aimed at improving understanding of the primary variables affecting restoration of abandoned farmlands. These variables include: water treatments, planting dates, mulch and water catchment, seasonal planting and plant species composition. The objectives of the study is to investigate the effect of land restoration practices on nitrogen, protein, fiber (NDF and ADF), ash and dry matter contents of three Atriplex species under different management and site conditions. The amount of nutrient contents in Atriplex species growing on abandoned farmlands under irrigation and conservation practices is higher when compared to no irrigation or control in Casa Grande research site. Atriplex species growing under mulch and water catchment condition had significantly higher nutrient content compared to other treatments. Furthermore, seasonal planting in abandoned farmlands affected the nutrient contents of Atriplex cultivars at the University of Arizona farm. The Atriplex cultivar planted in the winter had higher nutrient contents when compared to those planted in the summer and irrigated with a sprinkler irrigation system for some cultivars. A better understanding of how these variables affect nutrient contents of Atriplex species used in this restoration study will play an important role in directing public interest towards the revegetation of abandoned farmlands in southern Arizona for food production.

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Haddad, Ola. "Soilless Cultivation of Edible Plants for Phytoremediation." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-185047.

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Food security and eutrophication are two issues proven to have severe impacts on both humanity and the environment. This study suggests improving the local food security by utilizing phosphorus and nitrogen, available in severe eutrophic small lakes, in local food production, thus turning eutrophication from a problem into a resource. The study theoretically experiments the possibility of using eutrophic water in a greenhouse, where hydroponics is used as a cultivation method. The eutrophic water is pumped from the lake into the greenhouse, and then to the hydroponic system, which is expected to remediate the water, returning clean water to the lake. The objective of this process is to phytoremediate eutrophic water and simultaneously, produce edible commercial plants. Finding the best matching lake and plant nitrogen to phosphorus (N:P) ratio, is of key importance to optimize the remediation process. Based on data from a literature review, edible plants N:P ratios are found lower than typical lake N:P ratios, suggesting that, in some cases, edible plants in the hydroponic system would require additional nutrients to grow optimally. Finding the best matching lake and plant N:P ratio is thought to optimize the remediation process. Matching the lake and plant N:P ratio was conducted in Python.

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E, Xinyi. "Nutrients Recycling Strategy for Microalgae-based CO2 Mitigation System." UKnowledge, 2013. http://uknowledge.uky.edu/bae_etds/20.

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Coal-fired electricity production is the major emitter of CO2 and other greenhouse gases including NOx and SOx. Microalgae-based CO2 mitigation systems have been proposed to reduce the net CO2 emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation. In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed that thermal pretreatment enhanced the methane production rate for the first 7 days of digestion. Three operational factors were tested: heating temperature, heating duration and NaOH dosage. The combination of 10 min heating with 3~6% NaOH at 50 °C gave the highest cell wall destruction for all samples except oven-dried algae. The anaerobic digestate, rich in mineralized nutrients including ammonium and phosphate, potassium and magnesium ions, was tested as a possible nutrient source for the algae cultivation. To cope with the high solid content of the digestates, the dosage of the digestates was reduced or the solid particles were removed prior to addition to the microalgae. Both approaches worked well in terms of providing nutrients with minimal effect on light penetration. Using digestates without any sterilization did not cause contamination or other deleterious effects on the Scenedesmus growth rate. Harvesting microalgae cells was critical to ensure a continuous and robust growth rate. The used media could be recycled at least four times without altering the algae growth. Nutrient replenishment was the key for a healthy culture when used media was incorporated. The combination of used media and digestates can sustain a normal algae growth. Life cycle assessment was conducted on the system including the photobioreactor, the anaerobic digester, the biomass settling and dewatering and used media and nutrient recycling. Considering methane as the energy source, the overall energy return of the system was 2.4. CO2 mitigation rate was about 39% under current mitigation system.

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Dantas, Mendes Lipe Renato. "Long term assessment of created wetlands functioning within agricultural areas." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-17139.

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The polluted agricultural wastewater, after reaching marine recipients, can cause eutrophication. This problem can be tackled and mitigated by using constructed wetlands as water treatment systems. The fact that constructed wetlands work through long periods of time has led many scientists to evaluate how long they can still treat their influents effectively. The development and growth of vegetation and the accumulation of nutrients on the soils in a wetland are expected to occur. These processes change the wetland efficiency to remove pollutants. In this study, a set of wetlands constructed to treat agricultural wastewater were analyzed in different periods to assess if there is a difference in removal efficiency of nitrogen and phosphorus. This assessment was performed by analyzing the retention rate, k and k20 values, which are variables that quantify the nutrients removal, in different periods of each employed wetland. Some of the observations demonstrated differences when comparing different periods of the wetlands. The nitrogen removal presented better performance in one of the employed wetlands when this was older. Another employed wetland has not shown a clear difference between different periods. In the wetlands with high vegetation densities, the nitrogen removal was more stable over consecutive years. The occurrence of oscillations in nitrogen removal was observed more often in the wetlands with the highest vegetation densities over consecutive years. The phosphorus removal presented no clear differences between different periods. The results suggest that the removal of nitrogen improves after wetland creation due to the growth of vegetation. In addition, they suggest that wetlands with high vegetation densities tend to oscillate the nitrogen removal more or less often according to the density of the vegetation due to the balance between denitrification and decomposition. Further, the results suggest that the removal of phosphorus remains unchanged over longer periods than the periods considered in this study (four to six years) due to the deposition of organic matter on the soils.

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Wilson, Thomas Bachman. "Nutrient dynamics and fire history in mesquite (Prosopis spp.)-dominated desert grasslands of the southwestern United States." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279975.

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In desert grasslands of the southwestern United States, Prosopis velutina (mesquite), an N-fixing legume, has proliferated from historic drainage locations into more xeric grassland plains. This expansion is forming a more heterogenous soil nutrient topography in grasslands, N-pools are becoming localized under mesquite canopies, yet the rate and extent of this sequestration remains relatively unknown. Repeated prescribed burning has been used to control Prosopis distribution, but effects of fires on grassland soil nutrient distribution and aboveground plant biomass are also largely unknown. I examined recent research concerning P. velutina natural history, emphasizing characteristics that contribute to range expansion. I also evaluated Prosopis management practices---which include herbicide treatment, prescribed burning, grazing reduction, and mechanical removal---and management goals---which involve complete removal, no removal, and limited removal. Of these, limited removal is the most beneficial, using an herbicide application followed by periodic prescribed burning. In 1997 I established a study area at Fort Huachuca Military Reservation in southeastern Arizona, selecting two adjacent sites with similar soil composition and topography but different fire histories. I examined spatial and seasonal changes in composition and distribution of available soil N and litterfall. My results indicated these were more spatially and temporally heterogenous on sites with low fire frequency and high P. velutina stand development. In 1998 I selected nine sites at Fort Huachuca on two upland surfaces located < 1 km apart, with similar soil physical characteristics and fire frequencies ranging from 0 to 5 fires/decade. I evaluated relationships between fire frequency, soil nutrient status (pH, available P, organic C, total N, and available N), and aboveground plant biomass, including that of the non-native Eragrostis lehmanniana (Lehmann lovegrass). Soil pH and ammonium significantly decreased with increased fire frequency on one surface, and available P significantly decreased with increased fire frequency on the other surface. Available P and pH were significantly different between the 2 surfaces, but aboveground biomass was similar. Soil nutrient status and biomass were not related, suggesting plant-available soil nutrients may not control plant distribution or recovery following fire. E. lehmanniana biomass was negatively correlated with native grass and forb biomass, and tended to increase with increasing fire frequency. Surface litter and E. lehmanniana biomass were correlated, and may increase fire frequency, an important consideration when implementing grassland fire management practices.

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Soupir, Michelle Lynn. "Release and Transport of Bacteria and Nutrients from Livestock Manure Applied to Pastureland." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34471.

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Transport of fecal bacteria and nutrients from point and nonpoint sources to surface water bodies is of significant concern in Virginia and the United States. In Virginia, 4,320 river miles are impaired for one or more beneficial use and 72% of the streams are impaired due to pathogen indicators (VDEQ, 2002). Land applications of manure from confined animal systems and by direct deposit by grazing animals are both major sources of fecal bacteria and nutrients in runoff. Therefore, an understanding of the overland transport mechanisms for fecal bacteria and nutrients is very important for the development of best management practices to reduce loading of pathogens and nutrients to surface water bodies. The objectives of this study were to quantify the release and transport potential of three fecal bacterial indicators: E. coli, Enterococcus, and fecal coliforms; and nitrogen and phosphorus from land applied manure during runoff events. Another objective was to identify the Enterococcus species present in dairy manure and determine which species have the highest potential to be transported by runoff.

Release plots were established to study the in-field bacteria and nutrient release. The bacteria and nutrients released from the plots are available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, cowpies, and none or control) and three land type treatments: pasture with a history of poultry litter application (Turkey Farm), pasture with a history of liquid dairy manure application (Dairy Farm), and pasture with no prior manure application (Tech Research Farm) were studied. During a short but intense rainfall event, the highest bacterial release was measured under the cowpie treatment (E. coli concentrations ranging from 37,000 to >300,000 and FC concentrations ranging from 65,000 to >300,000). Pasturelands with a history of previous manure applications did not release higher bacteria concentrations compared with pasturelands which had never received manure applications. Pasturelands with a history of land application of liquid dairy manure and turkey litter had 143% and 94% higher TSS concentrations available to be transported off the field during overland flow events because of the build up of organic material on the soil surface. TP concentrations released from the cowpie, liquid dairy, and turkey litter treatments were 3.12 mg/L, 3.00 mg/L, and 1.76 mg/L, respectively.

Transport plots were developed to measure the concentrations of fecal bacteria and nutrients present in overland flow at the edge of the field. The bacteria flow-weighted concentrations were highest in runoff samples from the plots treated with cowpies (200,000 CFU/100 mL of E. coli and 234,000 CFU/100 mL of FC). The turkey litter had the highest concentration of dissolved phosphorus in runoff from pasturelands (1.22 mg/L), but the cowpie treatment had the highest concentrations of sediment bound phosphorus in runoff (0.73 mg/L). All three treatments investigated in this study contributed to phosphorus loading in surface waters and could potentially increase the risk of eutrophication. Total nitrogen concentrations from the transport plots exceeded the threshold for likely eutrophication problems for all treatments and the total nitrogen concentrations from plots treated with cowpies exceeded the threshold for severe eutrophication problems.

The Biolog System, a method of bacterial source tracking, was used to identify the different species of Enterococcus present both in the cowpie source manure and in the runoff collected from the transport plots treated with cowpies. The source manure is dominated by the Enterococcus mundtii (55%), Enterococcus gallinarum (20%), Enterococcus faecium (10%), and Enterococcus faecalis (10%). Enterococcus faecalis had the highest percentage of isolates present in runoff with a total of 37%, followed by Enterococcus mundtii which was present in 21% of the runoff events and Enterococcus gallinarum and Enterococcus faecium (11%).

Improvements in understanding the bacterial release and overland processes will enhance modeling of bacteria and nutrient transport, and provide a basis for a more realistic evaluation of the impacts of management practices implementation. The data from this study will serve as a baseline to model the release and transport of fecal bacteria and nutrients from agricultural watersheds to surface waters.

Master of Science

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Brooker, Michael R. "Physical and Chemical Characterization of Self-Developing Agricultural Floodplains." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1513778530623727.

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Joubert, Jorika. "The effect of different water and nutrient management strategies on the calcium content in apple fruit." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/395.

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Williams, Rachel. "Effectiveness of Biochar Addition in Reducing Concentrations of Selected Nutrients and Bacteria in Runoff." UKnowledge, 2016. http://uknowledge.uky.edu/bae_etds/40.

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Land application and storage of horse manure and municipal sludge can increase nutrient and bacteria concentrations in runoff. Biochar increases soil nutrient retention when used as a soil amendment. The objectives of this study were to determine if biochar, when mixed with horse manure or sludge, affects runoff concentrations of total Kjehldahl nitrogen (TKN), ammonia-nitrogen (NH3-N), nitrate (NO3-N), total phosphorus (TP), dissolved phosphorus (DP), total suspended solids (TSS), chemical oxygen demand (COD), and fecal coliforms (FC). Horse manure and sludge were applied to 2.4 x 6.1 m fescue plots (six each), with three plots of each material amended with 5-8% biochar w/w. Simulated rainfall (101.6 mm/h) was applied to the 12 treatment plots and three control plots. The first 0.5 h of runoff was collected and analyzed for the above-listed parameters. The data were analyzed using an ANCOVA, with SCS runoff curve number (CN) used as the covariate. In general, CN was directly correlated to runoff concentrations of parameters. Plots with low CN values displayed no treatment differences for any measured parameter. Biochar reduced runoff concentrations of TKN and NH3-N for municipal sludge treatments, and TKN, NH3-N, TP, TSS, and FC for horse manure treatments.

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Wiborgh, Hanna. "Where do the nutrients come from? : A case study from the agricultural landscape of Sibou village." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-126479.

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This study investigates the source of nutrients in an agricultural landscape in Kenya. Kapshoi furrow has its intake from Embobut River and flows through the village of Sibou until it reaches the plots in the lowland in Keu. The pH, electrical conductivity (EC), sediment transport, total nitrogen (N) mass flux and total phosphorus (P) mass flux all change when the furrow flows through the village. The most possible cause for the nutrients peaks is the farmers' goats, sheep and cows that walk freely in and around the furrow. This is counter to some existing local theories. The likely cause for the pH decrease and the EC increase are inflow of groundwater (springs) to the furrow. To secure safe drinking water it would be good to uphold the old rules in Sibou of (1) not to live in close proximity of the furrows and (2) not to bathe or do the dishes in the furrow water. This might be difficult due to a fast growing population.

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GALAMINI, Giulio. "Natural zeolitites in combination with struvite precipitation technology for the recovery of nutrients from agricultural wastewaters." Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2486767.

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The World Health Organization has emphasized the importance to start turning the perception of “nutrient-rich wastewaters”, from “wastes” to dispose of, to “resources”, useful for plant nutrition, but, despite this, 80% of municipal wastewaters globally produced are still discarded in the environment, without having been subjected to any treatment. On the other hand, the thoughtless use of excreta and derived materials for fertilization practices threatens the environmental systems, leading to pollution, soil degradation, and water contamination. The question of “how to efficiently dispose of nutrient-rich wastewaters” or, in other words, “how to improve the recycling of nutrients in agro-ecosystems”, remains thus a crucial topic for the sustainability of human activities. A promising technology consists in the precipitation of struvite crystals for the recovery of both nitrogen (N) and phosphorous (P). But, even if these processes are starting to scale up at industrial levels, the unbalance between the struvite components in wastewaters, as Mg2+, NH4+ and PO43-, remains one of the main issues for its implementation. The possibility to recover the excess of NH4+ before struvite precipitation may potentially increase the efficiency of struvite technologies. Within this thesis work, it was investigated a wastewater treatment process that uses natural zeolitites (rocks containing more than 50% in zeolite minerals) in combination with struvite precipitation, for the removal and recovery of N and P, in the form of struvite crystals and NH4+-N-enriched zeolitites. Before the wastewater treatment experiment, the NH4+-N adsorption properties of the applied zeolitite were characterized (experiment A) in terms of isotherms, kinetic models, and thermodynamic parameters, from livestock wastewater (pig manure), and two different grain sizes have been investigated: a granular zeolitite and a micronized one. Even if both showed interesting features, the micronized zeolitite demonstrated to reach higher adsorption capacities, with better temperature stability. This material was thus chosen for experiment B, where different treatment strategies have been investigated for the recovery of struvite from anaerobically digested wastewater. The investigated treatments were composed of two distinct steps: the 1st phase (zeolitite adsorption batch) tested the natural micronized zeolitite and a modified one (K+-enriched) for the reduction of NH4+-N loads. In the 2nd phase (struvite precipitation), 2 different Mg:NH4:PO4 molar ratios were tested, in particular, a condition of NH4+ excess (MR1) and another with Mg2+ in excess (MR2). Both these conditions were described in the literature as the best for struvite precipitation. The outcomes of experiment B suggested that the most feasible practice consists in the use of the natural zeolitites, in combination with the MR1 condition. This treatment showed indeed the highest nutrient removal efficiency, highest efficiency in struvite precipitation, and less alteration of the treated wastewater. The precipitate obtained was 89.9 mass % composed of struvite, poor in hazardous heavy metals, with 3.5% of nitrogen. The materials obtained, as the N-charged zeolitites, the struvite precipitates and the nutrient-depleted wastewater may potentially be used in agriculture, for crop nutrition, and/or as soil amendment. Even if the treatment described within this thesis work used livestock wastewaters and a derivate one, the methodology proposed may be appliable to any other nutrient-rich wastewater, as municipal ones.
L' Organizzazione Mondiale della Sanità (WHO) ha sottolineato l'importanza di iniziare a percepire le acque reflue animali e umane, come “risorse” invece che “rifiuti”. Nonostante questo, l'80% delle acque reflue municipali prodotte a livello globale vengono ancora gettate nell'ambiente senza essere state sottoposte ad alcun trattamento. D'altra parte, anche l'utilizzo sconsiderato come fertilizzanti minaccia i sistemi ambientali, portando a inquinamento, a degrado del suolo e alla contaminazione delle acque. La questione riguardo a "come smaltire in modo efficiente le acque reflue " o, ancora meglio, "come migliorare il riciclaggio dei nutrienti negli agro-ecosistemi", rimane quindi un argomento cruciale, la cui soluzione è necessaria per garantire la sostenibilità delle attività umane. Una promettente tecnologia consiste nella precipitazione di struvite per il recupero di azoto (N) e fosforo (P) dal refluo, ma lo sbilanciamento tra gli ioni costituenti (Mg2+, NH4+ e PO43-) all’interno delle acque reflue, è uno dei problemi principali per la sua implementazione, in particolare rispetto al forte eccesso di NH4+ che tali materiali presentano. È quindi spesso necessario incrementare Mg2+ e PO43-, andando ad incidere sui costi di produzione e alterando la qualità del refluo trattato. La possibilità di recuperare in maniera controllata l'NH4+ in eccesso, prima della precipitazione di struvite, può potenzialmente aumentare l'efficienza di questa tecnologia, diminuendo considerevolmente la necessità nell’utilizzo di reagenti. È stato quindi studiato un processo di trattamento di acque reflue agricole che utilizza zeolititi naturali (rocce contenenti > 50% di minerali zeolitici) in combinazione con la precipitazione di struvite, per la rimozione e il recupero di N e P. Preliminarmente sono state caratterizzate le proprietà di adsorbimento di NH4+ della zeolitite (esperimento A). Lo studio è stato eseguito su un refluo da allevamento suinicolo, studiando l’effetto della granulometria del materiale tramite due diverse granulometrie: zeolitite granulare e micronizzata. La zeolitite micronizzata ha dimostrato di raggiungere capacità di adsorbimento più elevate, con una migliore stabilità rispetto alla temperatura. Questo materiale è stato scelto per l'esperimento B, dove sono state studiate diverse strategie di trattamento per il recupero di struvite da un digestato. Il trattamento prevedeva due fasi: nella prima fase è stata applicata la zeolitite micronizzata, sia naturale che arricchita in K+, per la riduzione controllata del carico di NH4+ del refluo. Nella seconda fase, sono stati testati 2 diversi rapporti molari (Mg:NH4:PO4) per la precipitazione di struvite, in particolare, una condizione di eccesso di NH4+ (MR1) e un'altra caratterizzata da Mg2+ in eccesso (MR2). I risultati dell'esperimento B hanno suggerito che la metodologia più promettente consiste nell'uso di zeolitite naturale, in combinazione con il rapporto molare MR1 (NZT-S MR1). Questo trattamento ha infatti mostrato maggiore efficienza nella rimozione dei nutrienti, per la precipitazione di struvite e una minore alterazione finale del refluo trattato. Il precipitato ottenuto era composto per l'89,9% da struvite, povero di metalli pesanti potenzialmente pericolosi, e con un contenuto di azoto totale pari al 3,5%.I materiali ottenuti (zeolititi cariche in NH4+, precipitati di struvite e il refluo trattato) sono potenzialmente utilizzabili in agricoltura come fertilizzanti/ammendanti.La metodologia proposta può essere applicabile a qualsiasi acqua reflua ricca in nutrienti, come le acque reflue municipali.

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Dissertations / Theses on the topic 'Agricultural management of nutrients'

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