Evaluating The Impacts Of Climate And Stacked Conservation Practices On Nutrient Loss From Legacy Phosphorus Agricultural Fields

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Evaluating the Impacts of Climate and Stacked Conservation Practices on Nutrient Loss from Legacy Phosphorus Agricultural Fields

Author : Rachelle Leah Crow
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (135 download)

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Book Synopsis Evaluating the Impacts of Climate and Stacked Conservation Practices on Nutrient Loss from Legacy Phosphorus Agricultural Fields by : Rachelle Leah Crow

Download or read book Evaluating the Impacts of Climate and Stacked Conservation Practices on Nutrient Loss from Legacy Phosphorus Agricultural Fields written by Rachelle Leah Crow and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Agricultural nutrient loss in the Western Lake Erie Basin (WLEB) leads to elevated nutrient levels in Lake Erie, resulting in harmful algal blooms and anoxic conditions, decreased fish populations, and reduced recreation and tourism revenues. To combat this issue, the Ohio Phosphorus Task Force set a goal to decrease the phosphorus (P) load to the WLEB by 40% from 2008 spring loads. To meet this goal, efforts are underway to minimize the amount of P transported from agricultural fields to surface water using best management practices (BMPs). While many BMPs aim to decrease P loss by optimizing agricultural nutrient usage, some fields continue to have elevated soil test phosphorus (STP) levels even when nutrients have not been applied for decades. These fields, referred to as legacy P fields, contain more P within the soil profile than agronomically necessary and have substantial nutrient runoff potential. Because these sites disproportionately contribute to nutrient runoff, it is important to determine what variables impact and how best to manage nutrient loss from legacy P fields. Rainfall depth and intensity have been identified as driving factors causing P runoff from fields within agronomic STP levels. Better knowledge of the impact of precipitation and temperature on runoff from legacy P fields will improve management to minimize nutrient loss from these unique settings. This is especially valuable information as production and water quality management adaptations are made in reaction to climate change. To determine how weather variability impacts P runoff from legacy P fields, water quality and water quantity data was collected at 11 fields with Mehlich-3 P STP > 100 mg/kg in northwest Ohio for a total of 18.5 site-years, during which time 477 storm events each with > 6.35 mm (0.25 in) of precipitation were monitored. This study found that average nutrient concentrations within tile discharge from legacy P fields were 2.4 times (total P; TP) and 4-5 times (dissolved reactive P; DRP) larger than the equivalent on fields with agronomically appropriate STP (i.e., agronomic fields). Additionally, legacy P fields behaved similarly to agronomic fields during precipitation events: rainfall amount was the primary climatic variable affecting TP and DRP loads while tile discharge and nitrate loads were both largely affected by rainfall amount and event duration. By addressing fundamental questions about interactions between elevated STP fields, climate, and nutrient transformation and transport, this study provides greater insight to the significance of legacy P fields on water quality issues and therefore informs decisions on BMP selection and design. Stacked BMPs on fields with high nutrient loss potential are hypothesized to improve quality of runoff more than non-targeted or single practices. To measure the effectiveness of stacked conservation practices on a legacy P field, this study analyzed nutrient loss from a western Ohio field for nearly two years. The targeted subsurface tile drained 4.5 ha (11.1 acres) of the field to the first BMP, a ditch-style P removal structure (PRS) filled with electric arc furnace steel slag. The effluent from the PRS then discharged into a second BMP: a constructed wetland. Discharge moving through the stacked practices was monitored with bubbler flow meters and area velocity sensors and water samples were collected using automated water samplers at the inflows and outflows of each BMP. Between the inlet and outlet of the PRS, there was a 27% reduction in TP concentration and an 18% increase in DRP concentration. The wetland produced statistically significant and consistent reductions of TP loading and DRP loading by 30% and 18%, respectively. Although the PRS did not perform as designed, the stacked PRS and wetland in series had overall load reductions of TP (36%) and DRP (18%). The analysis of these stacked practices demonstrates that although one of the two BMPs performed poorly, there is a benefit to redundant designs, which provides insight on how to best implement BMPs on agricultural lands.

Assessing the Effects of Conservation Practices and Fertilizer Application Methods on Nitrogen and Phosphorus Losses from Farm Fields

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Author : Stephanie Ann Nummer
Publisher :
ISBN 13 :
Total Pages : 79 pages
Book Rating : 4.:/5 (11 download)

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Book Synopsis Assessing the Effects of Conservation Practices and Fertilizer Application Methods on Nitrogen and Phosphorus Losses from Farm Fields by : Stephanie Ann Nummer

Download or read book Assessing the Effects of Conservation Practices and Fertilizer Application Methods on Nitrogen and Phosphorus Losses from Farm Fields written by Stephanie Ann Nummer and published by . This book was released on 2016 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen and phosphorus runoff from agricultural lands and the subsequent impact on water quality has been of great concern in the United States, due to harmful algal blooms and anoxic zones in areas such as Lake Erie and the Gulf of Mexico. Conservation practices have been widely used to reduce the quantity of nutrients leaving a field, but there is a lack of research on the effectiveness of these practices using field scale data. The objective of this thesis is to quantify the effect of conservation practices on nitrogen and phosphorus runoff in farmlands. A meta-analysis was conducted using the Measured Annual Nutrient loads from AGricultural Environments (MANAGE) database created by the USDA-ARS. MANAGE is a compilation of 65 publications including data on nitrogen and phosphorus loads, runoff, land use, fertilizer application, and other field characteristics. The observational nature of the dataset makes direct comparisons from field to field impossible because of large variations in field characteristics. Thus, additional steps must be taken to estimate the effect of conservation practices on nutrient loss. To quantify this effect, I used propensity score matching and multilevel modeling, two statistical methods common for observational data. Propensity score matching shows that conservation practices have a significant reduction of 67.5% in total phosphorus, 83% in particulate phosphorus, and 67.3% in particulate nitrogen. Multilevel modeling results - calculated using two different computational methods - support these findings by showing a significant reduction of 57.7% in total phosphorus, 76.2% and 82.1% in particulate phosphorus (via the two methods), and 63.7% in particulate nitrogen. When examining different land uses and fertilizer application methods, the multilevel modeling showed that conservation practices had the most impact on row crops (e.g. corn and soybeans) and on farms fertilized via the injected or surfaced applied method. The results from this work represent the average effect of conservation practices on a national scale. At a regional scale, the effects of conservation practices may vary because of regional differences in agricultural practices and climate. To assist future research at regional and local scales, this thesis provides a Bayesian modeling framework for future quantification of these effects.

Understanding and Mitigating Phosphorus Losses in the Vermont Lake Champlain Basin at the Watershed and Field Scale in a Changing Climate

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Author : George Harrison Myers
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Understanding and Mitigating Phosphorus Losses in the Vermont Lake Champlain Basin at the Watershed and Field Scale in a Changing Climate by : George Harrison Myers

Download or read book Understanding and Mitigating Phosphorus Losses in the Vermont Lake Champlain Basin at the Watershed and Field Scale in a Changing Climate written by George Harrison Myers and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alteration of global nitrogen (N) and phosphorus (P) cycles to support livestock and crop production is the most significant driver of global nutrient surpluses. Losses of excess nutrients to the environment contribute to eutrophication of aquatic systems, leading to harmful algal blooms (HABs), hypoxia, and fish kills. Livestock and dairy production are directly linked to the acceleration of eutrophication via nutrient losses from animal manure. Lake Champlain has been experiencing HABs since the 1970s, and a total maximum daily load (TMDL) is in place to reduce P loading to the lake, with much of the reduction in P load being required to come from the agricultural sector. It is critical to understand nutrient movement and the impact of a changing regional climate in manure-based agricultural watersheds, as dairy farming is the primary agricultural sector in Vermont. Additionally, studying agricultural management practices to mitigate P losses is imperative to meet the target P load reductions set forth by the TMDL. The first portion of this thesis analyzes seasonal differences in nutrient movement in two manure-based agricultural watersheds in the Vermont Lake Champlain Basin (VT LCB) with varying extent of agricultural land use. The results show that the spring and summer had the smallest seasonal loads of total P (TP) and dissolved P (DP) in runoff. The smaller summer P loads appear to be related to periods of drought, while the smaller P loads in the spring are likely related to less manure P built up in the watershed that could be transported to surface waters. Approximately 40% of the cumulative TP load and 43% of the cumulative DP load was discharged from the watersheds in the fall. The increased fall TP and DP loads were likely due to the application of manure across the watersheds during this period. The data suggest that soil erosion is relatively less dominant as a driver of watershed P discharge during times when manure was available for transport post-application (e.g., fall and summer), and more closely linked to watershed P loss during times when less new manure was available (e.g., spring). The results suggest better management of manure application rates and timing as well as increased implementation of agricultural management practices are needed to address increased P transport throughout the year, and especially during the fall. The second portion of this thesis assesses the efficacy of edge-of-field (EOF) iron-based filters for P removal. In-field agricultural management practices such as no-till management and cover cropping target reductions in TP, but do not effectively address DP. EOF filters are a promising management practice for reducing DP losses. Storm runoff at the inlet and outlet of one subsurface and two surface EOF filters was monitored for 10 months. The subsurface filter proved very effective for soluble reactive P (SRP) and TP removal, removing 99% of cumulative SRP load and 91% of TP load from monitored events. The surface filters had varied results, with the east surface filter removing 19% of SRP load and 72% of TP load, and the west surface filter removing 52% of SRP load and having no effect on TP load. The findings highlight the importance of filter sizing and design to minimize the impact of sediment loading and preferential flow pathways on surface EOF filter performance. The study provides early evidence that tile drain filters are a highly effective management strategy for mitigating SRP and TP losses from agricultural fields.

The Impact of Spatial Decision Variables Influencing Crop Rotation on Phosphorus Load Reduction

Author : Seyedeh Nayyer Mirnasl Bonab
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (126 download)

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Book Synopsis The Impact of Spatial Decision Variables Influencing Crop Rotation on Phosphorus Load Reduction by : Seyedeh Nayyer Mirnasl Bonab

Download or read book The Impact of Spatial Decision Variables Influencing Crop Rotation on Phosphorus Load Reduction written by Seyedeh Nayyer Mirnasl Bonab and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-point source anthropogenic nutrient loading through intensive farming practices is a global source of water quality degradation by creating harmful algal blooms in aquatic ecosystems. Phosphorus, as the key nutrient in this process, has received much attention in different studies as well as conservation programs aimed at mitigating the transfer of polluting nutrients to freshwater resources. Central to conservation initiatives developed to maintain and improve water quality is the application of the Conservation Practices (CPs), introduced widely as practical, cost-effective measures with overall positive impacts on the rate of nutrient load reductions from farmlands to freshwater resources. Crop rotation is one of the field-based BMPs applied to maintain the overall soil fertility and preventing the displacement of the topsoil layers by surface water runoff across the agricultural watersheds. The underlying concept in the application of this particular BMP is a deviation from the monoculture cropping system by integrating different crops into the farming process. This way, cultivated soils do not lose key nutrients, which are necessary for crop growth, and the overall crop productivity remains unchanged in the landscape. The successful implementation of crop rotation highly depends on planning the rotation process, which is influenced by a variety of environmental, structural, and managerial factors, including the size of farmlands, climate variability, crop type, level of implementation, soil type, and market prices among other factors. Each of these decision variables is subject to variation depending upon the variability of other factors, the complexity of watersheds upon which this BMP is implemented, and the overall objectives of the BMP adoption. This study aims to investigate two of these decision variables and their potential impacts on phosphorus load reductions through a scenario-based hydrologic modeling framework developed to iv assess the post-crop rotation water quality improvements across the Medway Creek Watershed, situated in the Lake Erie Basin in Ontario, Canada. These variables are the spatial pattern of crop rotation and its level of implementation, assessed at the watershed scale through the modifications made to the delineation of the basic Hydrologic Response Units (HRUs) in the modeling process as well as certain assumptions in the management schedules, and decision rules required for the integration of crop rotation into the proposed modeling framework and optimal placement of this non-structural BMP across the watershed. The main modeling package utilized in this study is the Soil and Water Assessment Tool (SWAT), used in conjunction with the ArcGIS and IBMSPSS tools to allow for spatial assessment and statistical analyses of the proposed hydrologic modeling results, respectively. Following in-depth statistical analyses of the scenarios, the results of the study elicit the critical role of both factors by proposing optimal ranges of application on the watershed under study. Accordingly, to achieve optimal implementation results compared to the baseline scenario, which has the zero rate of implementation, conservation initiatives in the watershed are encouraged to consider the targeted placement of crop rotation on half of the lands under cultivation. Despite, having a statistically significant impact on water quality compared to the baseline scenario, the random distribution scenario is less effective than the targeted scenario in mitigation of total phosphorus load. Similarly, compared to the medium rate of implementation the targeted placement in a higher proportion of the cultivated areas did not lead to statistically significant results but may be considered depending upon the purpose and scope of implementation.

Animal Manure

Author : Heidi M. Waldrip
Publisher : John Wiley & Sons
ISBN 13 : 0891183701
Total Pages : 448 pages
Book Rating : 4.8/5 (911 download)

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Book Synopsis Animal Manure by : Heidi M. Waldrip

Download or read book Animal Manure written by Heidi M. Waldrip and published by John Wiley & Sons. This book was released on 2020-05-05 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of meat, milk, and eggs consumed in the United States are produced in concentrated animal feeding operations (CAFO). With concentrated animal operations, in turn comes concentrated manure accumulation, which can pose a threat of contamination of air, soil, and water if improperly managed. Animal Manure: Production, Characteristics, Environmental Concerns, and Management navigates these important environmental concerns while detailing opportunities for environmentally and economically beneficial utilization.

Minimizing Phosphorus and Nitrogen Loss from Agricultural Systems with Cover Crops and Tillage in Southern Illinois

Author : Ashani Thilakarathne
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (137 download)

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Book Synopsis Minimizing Phosphorus and Nitrogen Loss from Agricultural Systems with Cover Crops and Tillage in Southern Illinois by : Ashani Thilakarathne

Download or read book Minimizing Phosphorus and Nitrogen Loss from Agricultural Systems with Cover Crops and Tillage in Southern Illinois written by Ashani Thilakarathne and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production in Illinois has a significant impact on the economy and environmental footprint in the state and the Midwest region. Nutrient leaching from Midwestern agricultural fields is one of the major reasons for the hypoxic zone developed in the Gulf of Mexico. Winter-fallow and early spring (after fertilizer application) are the two most critical periods for nutrient leaching due to increased precipitation and availability of nutrients. Cover crops (CCs) in these seasons are a promising best management practice (BMP) to reduce nutrient leaching in the winter-fallow season. No-till (NT) and reduced tillage (RT) are some other BMPs that farmers in Illinois adopt to reduce erosion. The adoption of CCs is limited due to the lack of knowledge and data on the yield and environmental benefits of CCs in different climatic and soil regimes. Thereby, this doctoral dissertation addresses several critical questions about CC and tillage impacts in claypan soils of southern Illinois with four principal projects with multiple objectives. Research study 1 was a field experiment conducted from 2013-to 2021 to understand the effect of CCs (CCs vs. noCC) and two tillage (NT and RT) practices on soil nitrate-N leaching. The experimental design was a complete randomized design with CC treatments that had two levels (two crop rotations) corn-cereal rye (Secale cereale L.)-soybean-hairy vetch (Vicia villosa R.) [CcrShv] and corn-noCC-soybean-noCC [CncSnc] and tillage treatments with two levels (NT and RT) replicated three times in the field. Each plot had a pan lysimeter installed below the A horizon (22-30 cm depth) to collect water samples weekly or biweekly depending on the rainfall. The corn yield was significantly greater in RT rotations compared to NT rotations with a 36% increase in the yield in 2019 and 2021 corn rotations. The yield was significantly greater in CcrShv rotations compared to the CncSnc rotations. The greatest yield was observed in the interaction of CcrShv-RT in all years. This increase in yield is inversely correlated to the remaining soil N values when the N credit from CCs was not accounted for. Soil nitrate-N leaching was significantly greater in CcrShv rotations compared to the CncSnc rotation in 2021 indicating vetch CC biomass decomposition can lead to increased leaching losses if the window between CC termination and corn planting is not minimized. Precipitation during the early spring can play a vital role in flushing the newly applied fertilizer as well as the N released from decomposing CC residue. The excessively wet year of 2019 showed that N losses are dominated by both nitrate-N leaching and nitrous oxide emissions, but in a typical growing season N losses are dominated by leaching compared to emissions. Research study 2 was designed to better understand the N cycling and fate of applied N in a complete corn-soybean rotation in southern Illinois with CCs and tillage practices. The research was overlayed in the same field with the same crop rotation and tillage practices. In this study, 15N labeled urea fertilizer (9.2% atom) was applied before the corn and soybean seasons. Soil, water, and biomass samples were collected to understand N distribution in each pool. In the corn season in 2017 a significantly greater 15N recovery was observed in CC (CcrShv) plots compared to the noCC plots in the sample collected seven days after planting (DAP). In the CC and depth interaction, a significantly greater 15N recovery was observed in 15-30 cm depth showing that the increased macropores due to CCs can lead to subsurface movement of N through the topsoil. The 15N recovery in water samples was high in CncSnc rotations in the cereal rye season but was significantly greater in CcrShv rotations (8.95 kg ha-1) in hairy vetch seasons. In the two years of complete rotation, the cumulative 15N recovery (quantity derived from fertilizer in water) was significantly greater in CC rotation. In the corn plants, the 15N recovered from the soil was greater than the 15N recovered from fertilizer. This shows the importance of the residual N from prior fertilizer and organic matter input. In the cereal rye season, CCs recovered significantly greater 15N from fertilizer compared to noCC rotations, assuring that cereal rye is an effective nutrient scavenger. A similar pattern was observed in the hairy vetch season as well. However, the soybean 15N recovery was greater in noCC rotations compared to CC rotations. The third study was a field trial on CCs and tillage to understand their individual and combined impact on soil physical parameters. Soil physical parameters were first measured in 2014 and were repeated in 2021. Bulk density at the 0-5 cm depth was 5% lower in 2021 compared to 2014 with the lowest BD in CC rotations with RT practices. For the depth of 0-15 cm, the lowest BD was observed in CC rotation with RT but, the largest reduction was observed in the CC rotation with NT. The wet aggregate stability was improved from 15-28 % over the years in all rotations. The lowest percentage improvement was observed in noCC rotation with RT practice. Penetration resistance was significantly lower in CC plots for the depth of 0-2.5 cm. CCs further improved the time to runoff in plots even though the infiltration rates were not affected. Chemical soil health indices were not significant overtime for CCs or tillage practices. However, a large number of earthworm counts were observed in NT systems compared to RT systems. The final project was a field trial to identify the soil P response to the CC and tillage practices. For this study, three different CC rotations, [corn-cereal rye-soybean-hairy vetch / corn-cereal rye-soybean-oats+radish / corn-noCC-soybean-noCC] and two tillage practices (NT and RT) were used. Soil samples were collected after the corn harvest in 2015 and 2021 and were analyzed for soil Phosphorus (P), inorganic P fractions by Chan and Jackson method, and dissolved reactive phosphorus (DRP) in leachate. The soil Mehlich-3 and Bray-1 P values indicate a great concentration of P in 0-15 cm depth for both years. More refined sampling in 2021 showed that the majority of P in 0-15 cm depth concentrates at the near-surface soil, in 0-5 cm depth irrespective of the CC and tillage treatment. Inorganic soil P fractions were not significantly different between CCs or tillage practices over time. Yet, irrespective of the treatment the non- labile P forms increased in 2021in the soil compared to 2015. The average and cumulative DRP values were highly dependent on the precipitation amounts and timing. However, in general, NT systems had greater average and cumulative DRP leaching compared to RT in both years. In general, CCs in the winter-fallow season is a good recommendation for farms that seek to maximize their production with a minimal environmental footprint. In the long run, CCs can improve soil physical and chemical properties which ultimately can increase the yield potential for corn and soybean. The added benefit of N credit due to leguminous CCs can reduce the fertilizer inputs. The CC benefits including the reduction in nutrient leaching depend on the type of CCs used in the field. More importantly, the CC termination time will be critical to obtain the maximum benefit of CCs. Even though the NT practices improve soil physical properties, long-term NT can increase the risk of soil P stratification in near-surface soils and can ultimately lead to more P loss via erosion, runoff, and soil water leaching. However, the combined use of CC and NT practices can help minimize the potential for erosion and runoff.

Challenges and Successes in Identifying the Transfer and Transformation of Phosphorus from Soils to Open Waters and Sediments

Author : Donald S Ross
Publisher : Mdpi AG
ISBN 13 : 9783036524320
Total Pages : 224 pages
Book Rating : 4.5/5 (243 download)

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Book Synopsis Challenges and Successes in Identifying the Transfer and Transformation of Phosphorus from Soils to Open Waters and Sediments by : Donald S Ross

Download or read book Challenges and Successes in Identifying the Transfer and Transformation of Phosphorus from Soils to Open Waters and Sediments written by Donald S Ross and published by Mdpi AG. This book was released on 2021-12-21 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The anthropogenic loading of phosphorus (P) to water bodies continues to increase worldwide, in many cases leading to increased eutrophication and harmful algal blooms. Determining the sources of P and the biogeochemical processes responsible for this increase is often difficult because of the complexity of the inputs and pathways, which vary both in spatial and temporal scales. In order to effectively develop strategies to improve water quality, it is essential to develop a comprehensive understanding of the relationship of P pools with biological uptake and cycling under varied soil and water conditions. In this ebook, eight chapters cover the various aspects of basic-applied research on mineral-P interaction and how these reactions impact P mobilization, bioavailability, transfer, and speciation of P in different soil matrices using advanced analytical methods. Some of these methods include the application of XANES and field-based research related to stream bank legacy nutrients; natural and anthropogenic eutrophication and its relationship to climate change; and the evaluation of the impact of P due to (i) grazing systems, (ii) weathering and vegetation, and iii) soil and manure management practices. In addition, two review chapters take a holistic approach to cover an expansive area of P transformation processes along the cropland-riparian-stream continuum and the assessment of legacy P. Together, these contributions improve our current understanding of the reactions and processes that impact P concentration, speciation, cycling, loss, and transfer from agroecosystems.

Effects of Climate, Land Use, and Land Management on Phosphorus Cycling and Water Quality in the Yahara Watershed

Author : Melissa M. Motew
Publisher :
ISBN 13 :
Total Pages : 404 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Effects of Climate, Land Use, and Land Management on Phosphorus Cycling and Water Quality in the Yahara Watershed by : Melissa M. Motew

Download or read book Effects of Climate, Land Use, and Land Management on Phosphorus Cycling and Water Quality in the Yahara Watershed written by Melissa M. Motew and published by . This book was released on 2017 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Freshwater resources are critical to society and the biosphere, yet eutrophication due to phosphorus (P) enrichment plagues watersheds worldwide. Land use, land management, and climate represent important drivers of the P cycle, capable of altering the supply and transport of P across the landscape. This dissertation consists of three inquiries into how changing climate and land use/land management (LULM) may affect P cycling and water quality in the future, and what the implications might be for management. Using a model of the Yahara Watershed, I investigate how historical nutrient management practices, represented by "legacy P", have influenced current and future conditions of lake water quality. Results show that (1) legacy P has a significant and long-lasting effect on the lakes, (2) there is currently an overabundance of soil P in the watershed, and (3) terrestrial P may interact synergistically with extreme rainfall in affecting lake water quality. The second inquiry identifies a synergistic interaction between manure P and precipitation intensity in affecting water quality indicators at field, stream, and lake scales. The findings imply that high levels of terrestrial P supplied as manure can exacerbate water quality problems in the future as the intensity of rainfall events increases with climate change. The final inquiry uses long-term scenarios to examine the relative influences of climate and LULM in affecting water quality. Results show that while climate plays a dominant role, LULM also plays an important role in driving outcomes. Climate has more influence at stream and lake scales than at the field scale, suggesting an inherent limitation for field scale LULM to influence downstream water quality. Reducing over-application of P is the most effective management strategy under all scenarios. The results of my dissertation emphasize that the overabundance of P within the YW is a dominant biophysical control of surface water quality across spatial and temporal scales. Climate change will present a formidable challenge to the management of freshwater resources, yet strategies that focus on reducing legacy P and balancing P budgets on farms promise meaningful improvements in stream and lake conditions, as well as protective benefits.

Cover Crop and Phosphorus Fertilizer Management Effects on Phosphorus Loss and Nutrient Cycling

Author : Robert Elliott Carver
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Cover Crop and Phosphorus Fertilizer Management Effects on Phosphorus Loss and Nutrient Cycling by : Robert Elliott Carver

Download or read book Cover Crop and Phosphorus Fertilizer Management Effects on Phosphorus Loss and Nutrient Cycling written by Robert Elliott Carver and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Phosphorus (P) loss from non-point agricultural sources has been identified as a main contributor to degraded surface water quality throughout the United States. Excessive P inputs to surface waters can lead to eutrophication, increased water treatment costs, and negative health impacts. Therefore, agricultural best management practices (BMP) that promote water quality, through minimizing P loss, must be identified. Studies outlined in this thesis aim to determine the impacts of cover crops and P fertilizer placement on P loss in surface runoff and nutrient cycling in a no-till corn (Zea mays)-soybean (Glycine max) rotation and provide insight into how cover crop species selection and termination method affects potential P loss from crop tissue. The first study examined combined effects of cover crop and P fertilizer placement on total P, dissolved reactive P (DRP) and sediment losses in surface runoff from natural precipitation events. This large-scale field study was conducted near Manhattan, Kansas, at the Kansas Agricultural Watershed (KAW) Field Laboratory during the 2016 and 2017 cropping years. Two levels of cover crop [no cover crop (NC) and cover crop (CC)] and three levels of P fertilizer management [no P (CN), fall broadcast P (FB), and spring injected P (SI)] were used. Flow-weighted composite water samples were collected from precipitation events generating greater than 2.0 mm of surface runoff. Results from this study found the CC treatment increased DRP losses compared to NC in both cropping years; however, CC reduced sediment loss by over 50% compared to NC. Application of P fertilizer increased DRP losses compared CN in both cropping years, although SI resulted in lower quantities of DRP loss compared to FB. In addition, this study found that CC reduced biomass and yield of corn compared to NC and therefore decreased nutrient uptake, removal, and deposition during the 2017 cropping year. However, no negative impacts of CC on biomass or yield were observed during the 2015 (corn) and 2016 (soybean) cropping years. Application of P fertilizer increased the concentration of Melich-3 P and total P in the top 0-5 cm of soil compared to CN; however, no differences between P fertilizer management practice were observed for concentrations of Melich-3 P at 5-15 cm. A greenhouse-based study determined the impacts of cover crop species (brassica, grass, and legume), termination method (clipping, freezing, and herbicide), and time after termination (1, 7, and 14 days after termination) on total P and water-extractable P (WEP) release from cover crop biomass. Freezing increased WEP concentration of crop tissue by more than 140% compared to clipping and herbicide. Additionally, at 7 and 14 days after termination, both concentration of WEP and fraction of WEP compared total P increased compared to 1 DAT. Findings from these studies suggest the use of cover crops may unintentionally result in greater DRP losses in surface runoff. However, addition of a cover crop can dramatically reduce erosion losses. In addition, cover crop species selection can directly impact the quantity of P being taken up and released by crop tissue. Understanding the impact of crop species selection may help create new BMPs which aim to reduce P loss.

Cover Crop and Phosphorus Fertilizer Management Implications for Water Quality in a No-till Corn-soybean Rotation

Author : Robert Elliott Carver
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Cover Crop and Phosphorus Fertilizer Management Implications for Water Quality in a No-till Corn-soybean Rotation by : Robert Elliott Carver

Download or read book Cover Crop and Phosphorus Fertilizer Management Implications for Water Quality in a No-till Corn-soybean Rotation written by Robert Elliott Carver and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phosphorus (P) is an essential nutrient required for crop growth with finite global reserves. Although naturally occurring concentrations of total P in soils may greatly exceed crop demand, quantities of readily plant-available P in soil solution are typically very low. As such, agricultural producers regularly apply P-containing fertilizers to help optimize crop yields. While applications of P fertilizers may improve crop performance, losses of P from non-point agricultural sources are a known contributor to the degradation of surface water quality with excessive P inputs leading to eutrophication, harmful algal blooms, and increased water treatment costs. Acknowledging the importance of P in production agriculture and the role it plays in water quality it is imperative to develop agricultural management systems designed to promote crop yields while protecting water quality. This study explores the interplay between winter grown cover crops and P fertilizer management practice in relation to annual concentrations and loads of total suspended solids, total P, and dissolved reactive P in surface runoff generated by natural precipitation events for a no-till corn (Zea mays)-soybean (Glycine max) rotation located in the Central Great Plains. To explain the mechanisms behind the potential implications of altering cover crop and/or P fertilizer management practice in relation to water quality, this study examined temporal/seasonal variability in surface runoff water quality, changes in soil fertility status, and the impact of winter cereal cover crop species on potential P release and nutrient cycling. The majority of this research was conducted at the Kansas Agricultural Watershed (KAW) field laboratory located near Manhattan, KS, USA, from September 2015 through September 2019. This study utilized three methods of P fertilizer management (no P, fall broadcast P, and spring injected P) each expressed with and without a winter grown cover crop. The spring injected method of P fertilizer application consistently lost less total P and DRP compared to the fall broadcast method of applying P fertilizer highlighting the importance of using P fertilizer placement to protect water quality. Findings from this study show that the addition of a cover crop during a normally fallow period increased dissolved reactive P loss in 3 of 4 years representing an unintended consequence of a traditionally recognized conservation practice. Cover crops also decreased sediment loss with greater reductions in sediment loss coming from the P fertilized cover crop treatments. Soil test data for samples collected from KAW field lab found that spring subsurface placement of P fertilizer did not result in lesser concentrations of either Mehlich-III not total P in the top 0-5 cm compared to fall broadcast P. The spring injected P fertilizer without a cover crop treatment had lesser concentrations of water-extractable P (WEP) in the top 0-2.5 cm compared to the fall broadcast with and without cover crop treatments; however, when a cover crop was added to the spring injected treatment, WEP was found to be equal to the two fall broadcast treatments The final portion of this research was conducted from fall 2019 through fall 2021 at locations near both Manhattan, KS, USA and Leonardville, KS, US, and examined the impact of six choices in winter cereal cover crops [included winter barley (Hordeum vulgare), winter oat (Avena sterilis), cereal rye (Secale cereale), triticale (X Tritico-secale), winter wheat (Triticum aestivum), and Cereal Killer Blend (1:1:1:1 of barley:oat:rye:triticale)] on P release from cover crop tissue, residue persistence, and the effect of cover crop choice on nutrient cycling throughout the cash crop growing season. This study found winter wheat to have the greatest potential for P release immediately following termination; however, after one week post termination, P concentrations in winter wheat residues were similar to other observed cover crops. Oats were observed to have lowest residue persistence and also to release assimilated nutrients faster than the remaining species. Marginal differences between winter barley, cereal rye, and triticale were observed with regards to P concentration, residue persistence, and nutrient cycling; however, these differences were not biologically significant. Results from this and the aforementioned studies highlight the importance and implications of management decisions when developing agricultural management practices to protect surface water quality.

Recommendations for Regulating Phosphorus from Livestock Operations in Manitoba : Final Report

Author : Manitoba Phosphorus Expert Committee
Publisher :
ISBN 13 :
Total Pages : 32 pages
Book Rating : 4.:/5 (69 download)

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Book Synopsis Recommendations for Regulating Phosphorus from Livestock Operations in Manitoba : Final Report by : Manitoba Phosphorus Expert Committee

Download or read book Recommendations for Regulating Phosphorus from Livestock Operations in Manitoba : Final Report written by Manitoba Phosphorus Expert Committee and published by . This book was released on 2006 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Phosphorus Security in Warm-Season Perennial Grasslands in NE Wisconsin

Author : Dustin Nelson
Publisher :
ISBN 13 :
Total Pages : 160 pages
Book Rating : 4.:/5 (124 download)

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Book Synopsis Phosphorus Security in Warm-Season Perennial Grasslands in NE Wisconsin by : Dustin Nelson

Download or read book Phosphorus Security in Warm-Season Perennial Grasslands in NE Wisconsin written by Dustin Nelson and published by . This book was released on 2020 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mitigation of water quality degradation from extensive, intensive agriculture is an ongoing global challenge. In many cases, remediation approaches must go beyond adjusting current practices, as previous management has led to a buildup of legacy soil phosphorus (P) in agricultural fields that is both difficult to remove and negatively impacts soil health and downslope water quality for decades. Perennial, warm-season grasslands have been suggested as one viable option to enhance P security in these fields. With deep, robust root systems, and significant aboveground biomass, warm-season grasslands have been shown to improve overall soil health, soil aggregate structure, soil porosity, and soil organic carbon (SOC) contents in previously cropped fields. These changes are expected to alter the location and nature of soil P, sequestering it within more stable biomass and soil organic matter pools, thereby increasing P security within the system. Surprisingly, few studies have directly evaluated changes in Bray-P concentration following conversion into warm-season grasslands, with a particular scarcity of information available on vertical changes within the soil profile during this transition. This project seeks to improve understanding of the effects warm-season grassland establishment on soil P security and mitigation efforts in high P agricultural soils in northeastern Wisconsin. These questions were evaluated in a warm-season grassland established on a formerly cropped field within the Oneida Nation, Brown County, WI by evaluating changes in vertically segregated and depth-cumulative soil properties measured both at the time of grassland establishment and six years later. At the time of grassland establishment, the field supported an average Bray-P concentration of 100.3 ppm in the top 30 cm of the soil profile; this level is considered excessive for Wisconsin. Both Bray-P concentrations and soil mass-adjusted Bray P decreased in the top 10 cm of the soil over the six-year study. Decreases appeared greater in soils with higher initial bulk densities and Bray P levels. Soil bulk density (BD) also decreased in the top 5 cm of the soil, and in the cumulative increment to a 30 cm depth. Additionally, total SOC and percent SOC accumulated in the top 10 cm of the soil, with greater increases observed in soils with lower initial C levels. A mass balance approach incorporating the findings of this study with previous work from the same site suggests that plant biomass held more P than was accounted for in decreases observed in the top 30 cm of the soil profile. These results suggest plant mining of soil P from deeper in the soil profile, and/or liberation of additional plant-available soil P from pools not measured, and a limited likelihood for significant P leaching from this system, despite very high soil Bray P levels. Overall, this research has shown, that even without harvest, in just 6 years, warmseason grasses increased P security and soil health in a high P agricultural soil in NE Wisconsin. Decreases in total Bray P, along with a decrease in soil BD and an increase in soil organic carbon have improved overall soil health, while converting reactive soil P into more secure organic pools. If combined with annual harvesting of aboveground biomass, this approach may be a particularly effective short and long-term option for managing soil P hotspots (i.e. excessive soil P) within agricultural watersheds. Our research shows that among candidate locations, those areas with highly compacted, organic C depleted, and P-enriched soils are likely to see the greatest improvements to overall soil health and P security when converted to grasslands.

Phosphorus Loss Assessment in North Carolina

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (656 download)

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Book Synopsis Phosphorus Loss Assessment in North Carolina by :

Download or read book Phosphorus Loss Assessment in North Carolina written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Increased concern about potential losses of phosphorus from agricultural fields receiving animal waste has resulted in the implementation of new state and federal regulations related to nutrient management. In response to strengthened nutrient management standards that require consideration of phosphorus (P), North Carolina has developed a site-specific P indexing system called the Phosphorus Loss Assessment Tool (PLAT) to predict relative amounts of potential P loss from agricultural fields. The objectives of this study were threefold: (i) to predict the percentage and types of farms that will be forced to change management practices due to implementation of the PLAT index (ii) to evaluate the predictive ability of PLAT using sensitivity/uncertainty analysis; (iii) to establish whether the method of predicting soil P used in PLAT, Mehlich-3 soil test P, is an adequate proxy for a more descriptive measure of soil P, namely the oxalate degree of P saturation. Based on a statistically random sampling of agricultural sites in all 100 counties, approximately 8% of producers in the state will be required to apply animal waste or inorganic fertilizer on a P basis rather than a nitrogen basis, with the percentage increasing for farmers applying animal waste (~27%). The tool predicted the areas in the state that are known to be disproportionately vulnerable to P loss due to histories of high P applications, high densities of animal units, or soil type and landscapes that are most susceptible to P loss. Statistical evaluation of the tool showed that soluble loss pathways, surface runoff and subsurface drainage, impact predictions of P loss more than either loss of P through erosion or applied source. Sensitivity to input factors related to the different methods for estimating soluble losses between naturally and artificially drained conditions varied depending on input values. Predicted P losses from organic soils were drastically more sensitive to soil test P than other soi.

Understanding Human Impacts on the Phosphorus Cycle

Author : Graham MacDonald
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (921 download)

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Book Synopsis Understanding Human Impacts on the Phosphorus Cycle by : Graham MacDonald

Download or read book Understanding Human Impacts on the Phosphorus Cycle written by Graham MacDonald and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Modern agriculture has led to fundamental changes in the phosphorus (P) cycle that pose agronomic and environmental challenges at all scales. Phosphorus is a non-renewable resource that is critical to food production because of its role as an essential plant nutrient. At the same time, P runoff from agricultural systems contributes to water quality degradation worldwide. Recent research has begun to illuminate the dimensions of P use in agriculture and its broader sustainability implications, yet there is limited understanding of how these disparate issues are connected across scales. In this thesis, I explore important knowledge gaps related to spatial and temporal changes in P flows due to human activity, their drivers, and some of the implications for large-scale management of soil P and water quality. With the first study, I conducted a global analysis to better understand the contemporary distribution of agronomic P use for croplands. The spatially detailed results revealed that disparities in the magnitude of P applied to cropland soils as fertilizer and manure relative to crop P use occur across most regions, but with considerable spatial variation. Although inputs of P fertilizer (14.2 Tg of P/yr) and manure (9.6 Tg of P/yr) collectively exceeded P removal by harvested crops (12.3 Tg of P/yr) at the global scale, P deficits covered almost 30% of the global cropland area. I then present a comprehensive analysis of the United States agricultural system, exploring how globalization exacerbates changes to regional P cycling. This study considered how limited national P fertilizer supplies are allocated at the interface between trade, biofuel production, and diets. Total mineral P used in the US can be traced predominantly to accumulation in domestic agricultural soils (28%), post-harvest losses (40%), or biofuel refining (10%). Only 8% of mineral P use was ultimately consumed in domestic diets, while one quarter of domestic P fertilizer use was allocated to producing exports. In turn, agriculturally-driven changes in soil P pools could have long-term ecological implications given the slow cycling of P in some soils. I conducted a comprehensive meta-analysis to assess evidence for these legacy effects throughout the world, indicated by either enriched or depleted soil labile and total P pools following agricultural abandonment. This global meta-analysis revealed potentially large and enduring legacies of past agriculture on soil P pools across different regions and soil types, but with some reduction in the magnitude of these changes over time since abandonment. Finally, I considered the roles of watershed anthropogenic and biophysical characteristics on P loading to lakes to aid in the development of large scale lake eutrophication risk models. I used a multi-faceted statistical approach with recent global land use and hydrological data to predict lakewater total phosphorus (TP) concentrations across a representative sample of >1000 lakes worldwide. Global lake TP predictions from three unique statistical methods explained from 50% to as much as 79% of the variation in observed TP, with relatively low error rates. Collectively, this work sheds new insight on agricultural modifications to the global P cycle arising from past and present nutrient management as well as how these might influence both soil P pools and water quality over time. There is growing need to balance local context (e.g., soil types, management histories, and livestock densities) with the cumulative implications these have on limited P reserves at the national or global level (e.g., closing regional P imbalances and accounting for the effects of trade). Greater attention to the spatial variation in both problems and solutions related to P, as well as their complex temporal dimensions, will be essential for advancing the science and policies needed to achieve greater P sustainability in agriculture while simultaneously ensuring healthy aquatic ecosystems." --

Impacts of Freeze-thaw Processes on Phosphorus Release from a Variety of Cover Crop Species in a Temperate Climate

Author : James Cober
Publisher :
ISBN 13 :
Total Pages : 86 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis Impacts of Freeze-thaw Processes on Phosphorus Release from a Variety of Cover Crop Species in a Temperate Climate by : James Cober

Download or read book Impacts of Freeze-thaw Processes on Phosphorus Release from a Variety of Cover Crop Species in a Temperate Climate written by James Cober and published by . This book was released on 2018 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cover crops (CC) are grown by farmers as an agricultural best management practice (BMP) to improve soil health during the non-growing season (NGS), and potentially reduce soil erosion. Some managers have cautioned against the use of CC due to their potential to act as sources of phosphorus (P) following exposure to freeze-thaw cycles (FTC), given that P has been strongly linked to eutrophication and algal blooms in freshwater systems. Existing literature on the effects of FTC on CC has indicated that the degree of P leaching may be influenced by multiple factors, including the number and/or magnitude of FTC, CC species, and the duration, intensity, and type of leaching event. However, much of the research has been done in laboratory studies, using conditions that are not representative of temperate climates or practices used in Southern Ontario. The objectives of this thesis were to evaluate the effects of FTC intensity and CC species on P release, using conditions and CC species commonly used in Ontario. These objectives were addressed in two separate experiments. The first experiment was done in the laboratory, where clippings of five CC species were exposed to five FTC at varying intensities (4 °C, -4 to 4 °C, -18 to 4 °C, and -18 to 10 °C), prior to extraction of P and nitrogen (N). The impact of termination was evaluated by comparing living CC samples to CC which were terminated with glyphosate. The second experiment was done in the field, and included seven plots of different CC species and mixtures. Plant and soil samples were analysed for P content throughout the NGS, and runoff and shallow groundwater were sampled on an event basis to evaluate the timing of P release from CC and the pathways through which the P moved. This thesis showed that CC species ranged greatly in P released after FTC, but N leaching was unaffected. Heavy frost ( -18 °C) increased P release, particularly from frost-intolerant species, whereas minimal FTC ( -4 °C) did not. Termination resulted in increased P and ammonium-N release from all species, but did not have an additive effect in combination with FTC. In a field setting, P release from CC was smaller in magnitude than was observed in the lab, consistent with the more moderate air temperatures that occurred. However, P release from CC was not related to P concentrations in surface soils and shallow groundwater, and, the pool of water extractable P was much smaller in the CC than in surface soil (5 cm). This thesis has shown that the tested CC species did not present risk for increased edge of field P loss, which is predicted to be consistent with other CC species grown in temperate climates. Planting CC should continue to be promoted as a BMP in Southern Ontario; however, in regions with colder climates, frost-tolerant CC species are recommended.

A Study of Phosphorus Nutrient Budgets, Crop Uptake and Availability in a Long-term Field Trial 1922-2010, Assessing the Implications for Organic Farming Practices

Download A Study of Phosphorus Nutrient Budgets, Crop Uptake and Availability in a Long-term Field Trial 1922-2010, Assessing the Implications for Organic Farming Practices PDF Online Free

Author : Richard J.V. Hunt
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis A Study of Phosphorus Nutrient Budgets, Crop Uptake and Availability in a Long-term Field Trial 1922-2010, Assessing the Implications for Organic Farming Practices by : Richard J.V. Hunt

Download or read book A Study of Phosphorus Nutrient Budgets, Crop Uptake and Availability in a Long-term Field Trial 1922-2010, Assessing the Implications for Organic Farming Practices written by Richard J.V. Hunt and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

A Framework for Assessing Effects of the Food System

Author : National Research Council
Publisher : National Academies Press
ISBN 13 : 030930783X
Total Pages : 340 pages
Book Rating : 4.3/5 (93 download)

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Book Synopsis A Framework for Assessing Effects of the Food System by : National Research Council

Download or read book A Framework for Assessing Effects of the Food System written by National Research Council and published by National Academies Press. This book was released on 2015-06-17 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: How we produce and consume food has a bigger impact on Americans' well-being than any other human activity. The food industry is the largest sector of our economy; food touches everything from our health to the environment, climate change, economic inequality, and the federal budget. From the earliest developments of agriculture, a major goal has been to attain sufficient foods that provide the energy and the nutrients needed for a healthy, active life. Over time, food production, processing, marketing, and consumption have evolved and become highly complex. The challenges of improving the food system in the 21st century will require systemic approaches that take full account of social, economic, ecological, and evolutionary factors. Policy or business interventions involving a segment of the food system often have consequences beyond the original issue the intervention was meant to address. A Framework for Assessing Effects of the Food System develops an analytical framework for assessing effects associated with the ways in which food is grown, processed, distributed, marketed, retailed, and consumed in the United States. The framework will allow users to recognize effects across the full food system, consider all domains and dimensions of effects, account for systems dynamics and complexities, and choose appropriate methods for analysis. This report provides example applications of the framework based on complex questions that are currently under debate: consumption of a healthy and safe diet, food security, animal welfare, and preserving the environment and its resources. A Framework for Assessing Effects of the Food System describes the U.S. food system and provides a brief history of its evolution into the current system. This report identifies some of the real and potential implications of the current system in terms of its health, environmental, and socioeconomic effects along with a sense for the complexities of the system, potential metrics, and some of the data needs that are required to assess the effects. The overview of the food system and the framework described in this report will be an essential resource for decision makers, researchers, and others to examine the possible impacts of alternative policies or agricultural or food processing practices.