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Evaluating Management Practices To Limit Phosphorus Losses From Agricultural Fields In The Castor Watershed Using The Wend Model
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Book Synopsis Evaluating Management Practices to Limit Phosphorus Losses from Agricultural Fields in the Castor Watershed Using the WEND Model by : Carolyne Choquette
Download or read book Evaluating Management Practices to Limit Phosphorus Losses from Agricultural Fields in the Castor Watershed Using the WEND Model written by Carolyne Choquette and published by . This book was released on 2005 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The model was used to examine the impacts of crop rotations, fertilizer application and tillage management on TP export. For the Castor watershed, the soil test P increased at a mean rate of 3.71 kg Mehlich-III P ha -1 yr-1, equivalent to a mean input of about 32 kg P2O5 ha-1 yr-1 in excess of plant requirements, assuming current field management practices remain constant." --
Book Synopsis Development and Validation of a Critical Source Area Index Tool to Identify Areas Vulnerable to Phosphorus Loss by : Emily Lesher
Download or read book Development and Validation of a Critical Source Area Index Tool to Identify Areas Vulnerable to Phosphorus Loss written by Emily Lesher and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Chesapeake Bay Watershed (CBW) has experienced water quality deterioration caused by diffuse agricultural phosphorus and nitrogen runoff entering the bay area. Agricultural decision support tools (DSTs) can help to not only improve commodity production, but also reduce pest and disease damage and reduce nutrient pollution. In the U.S. a commonly used DST is the Phosphorus Index (P Index), which is a field-based tool that identifies critical source areas (CSAs) vulnerable to P loss by evaluating source and transport factors; a high P-Index field would benefit from management changes to reduce P loss risk. An alternative approach is the identification of CSAs using high resolution landscape digital elevation models to identify within field intersections between high runoff potential and high soil phosphorus concentrations. Identifying CSAs as an approach for mitigating P loss from agricultural watersheds has revealed that often small portions of a watershed are responsible for the majority of pollutant loads. An example high resolution digital elevation model tool, the CSA Index, was developed in Ireland to target the most at-risk areas in a field for producing high runoff amounts and high P soils. The CSA Index is developed using plant available P measures like Mehlich-III P. However, studies investigating if forms of soil P beyond Mehlich-III extractable P should be monitored to reduce P losses are lacking. In this thesis I apply the CSA Index to four case study areas within the WE-38 sub-watershed of the greater CBW. The CSA Index generation was assessed using both a shallow soil sampling, 0- to 5- cm, and a standard agronomic sampling depth, 0- to 15- cm approaches at different depths. The results of the CSA Index are compared to the Pennsylvania P Index results run on each of the fields located within the case study areas to determine how areas vulnerable to P loss are identified and best management practice (BMPs) recommendations are made using each DST as a guide. I then performed intense sub-field scale soil sampling and re-run the CSA Index. These results were used to evaluate CSA Index results when soil P concentrations were derived from standard agronomic soil sampling and the more intensive sub-scale field sampling. Lastly, I examined different extraction approaches for measuring forms of phosphorus in the soil. I aimed to determine if forms of phosphorus vulnerable for runoff are missed by Mehlich-III P extraction methods and whether the presence or absence of a CSA influences the P concentrations. I found that the CSA Index and P Index differ in their identification of areas vulnerable to P loss. The P Index identified 15 out of 19 fields as being a "low risk" of P loss despite the CSA Index identifying CSAs in some of these "low risk" fields. The use of the CSA Index in combination with the P Index allowed for a discussion of BMPs for these case study areas. Recommendations to reduce P loss included extension of riparian buffers, crop conversion to permanent hay, and changes in field boundaries. It was determined that the best approach for applying BMPs to fields is to use the CSA Index initially to target CSAs on a smaller sub-field scale as well as identify flow pathways that may influence management changes. The P Index should then be used to drive management changes on the remaining landscape. Three of the four sub-watersheds saw an increase in CSA area at the 0- to 15- cm which resulted in more vulnerable areas of the landscape being identified at this deeper depth. The CSA Indices generated using the sub-scale soil sampling data showed that in all case study areas CSA are decreased with the more intensive sampling approach when compared to standard agronomic sampling. Despite the decrease in CSA area the agronomic sampling models still identified the majority of the most at-risk areas. The cost of performing sub-scale sampling as well as analyzing the data is a deterrent for using this sampling approach to run the CSA Index. For this reason and the fact that the models derived using agronomic sampling still succeeded in identifying CSAs it was suggested that soil P data determined using standard agronomic soil sampling be used to run the CSA Index. The evaluation of forms of phosphorus and methods used to measure them revealed that Mehlich-III P was a better predictor of total P than OP was and that Mehlich-III P concentrations increased exponentially as total recoverable 3050B P concentrations increased. Further investigation is needed to better understand the relationship between CSA and non-CSA areas and the forms of phosphorus present in the soils of these areas. Results from this thesis show how the use of the CSA Index in the CBW can further mitigate P loss from agricultural fields by precisely identifying within field CSAs that current DSTs like the P Index were not designed to identify. The widespread availability of LiDAR data across the region has dramatically reduced the cost of CSA Index development. Available soil testing data, or existing data ranges, could be used with LiDAR data to rapidly develop the CSA Index across CBW member states. The index should be evaluated in other physiographic provinces with less topographic driven surface hydrology to assess how it will perform in such landscapes. Future studies to validate the CSA Index should also include runoff monitoring of nutrient loads to adjacent waterbodies.
Book Synopsis Evaluation of Best Management Practices to Reduce Phosphorus and Sediment Loading in Gully Creek Watershed Using SWAT by : Phurailatpam Sharma
Download or read book Evaluation of Best Management Practices to Reduce Phosphorus and Sediment Loading in Gully Creek Watershed Using SWAT written by Phurailatpam Sharma and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Great Lakes hold over 20% of the earth's surface fresh water. Due to intense agricultural practices, the ecosystems of the Great Lakes have deteriorated. As the water pollution caused by agricultural activity is non-point source pollution, it is much harder to assess the pollution as compared to point sources of pollution where we can identify the sources of pollution easily. With the help of mathematical modeling, we can make a reasonable assessment of such pollution as well as provide different options (best management practices (BMPs)) for mitigating the problem. The Soil & Water Assessment Tool (SWAT) was selected to model the hydrology of the Gully Creek watershed in Ontario. SWAT is a watershed scale, continuous simulation model. Available data were used to calibrate and validate the model, and the Nash-Sutcliffe Efficiency (NSE), Percent Bias (PBIAS), and Coefficient of Determination (R2) statistics were used to evaluate the model's performance for simulating flow, sediment yield, and phosphorus yield. Due to the scarcity of observed data, calibration was performed for flow, sediment, and phosphorus between the start of 2011 and 2013. Flow calibration of the model was found to be satisfactory, with an NSE of 0.5, a PBIAS of 24.8%, and an R2 of 0.53. Calibration of sediment yield did not provide satisfactory results for NSE, PBIAS, and R2, with values of -0.75, 33.8%, and 0.14, respectively. Additionally, total phosphorus load was tested based on the calibration results, and it too did not provide satisfactory results. A "no BMP" scenario was created to evaluate the effectiveness of current and potential BMPs. "Retire to Forest" and "Retire to Pasture" reduced the total phosphorus load the most. Compared to the present practice, "Retire to forest" reduced phosphorus loss by 90%, compared to 73% under "pasture retirement." Conservation tillage BMPs could reduce the phosphorus burden. No-till BMP reduced phosphorus by 23% annually and 16% during the growing season, while minimum tillage reduced it by 8% annually and 1% during the non-growing season. Vegetated filter strips (VFS) at field boundaries reduced phosphorus loss (61%). The cover crop BMP was found to reduce annual phosphorus loss by 13%, whereas during spring, it shows a considerable reduction (29%). This study demonstrates how BMPs and hydrological modeling using SWAT will assist planners in controlling soil and water pollution at the watershed scale. The current study demonstrates conservation methods and offers practical guidance on how to choose the best BMPs for agricultural watersheds"--
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.
Book Synopsis Agriculture and Phosphorus Management by : Andrew N. Sharpley
Download or read book Agriculture and Phosphorus Management written by Andrew N. Sharpley and published by CRC Press. This book was released on 1999-12-20 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the Chesapeake Bay as a case study, Agriculture and Phosphorus Management discusses the impact and management of phosphorus in watersheds. Although urban and other sources contribute phosphorus to the Bay, the papers presented focus on how its role in agriculture impacts water quality. They review the new guidelines and legislation slated for implementation by 2002 directed towards sustainable nutrient management and strategies for implementing them. Phosphorus, an essential element for plant and animal growth, has long been recognized as necessary to eliminate deficiencies and to maintain profitable crop and livestock production. It can increase the biological productivity of surface waters by accelerating eutrophication. Human activities accelerate the rate of eutrophication - principally by increasing the rate at which phosphorus enters the aquatic system. Written by experts from a range of disciplines Agriculture and Phosphorus Management provides a deeper understanding of the diverse, dynamic, and complex factors controlling the impact of agricultural phosphorus management on production and water quality. Each contributor addresses the questions: what do we know, what do we still need to know, where are the major gaps in our knowledge, and how does the information relate to phosphorus management strategies in the Bay Watershed, and other watersheds? As a result this series of papers provides a unique collection of information of regional, national, and international significance and gives prioritized phosphorus management options for not only the Chesapeake Bay Watershed, but for watersheds around the world.
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.
Book Synopsis Development and Evaluation of RZWQM2-P by : Debasis Sadhukhan
Download or read book Development and Evaluation of RZWQM2-P written by Debasis Sadhukhan and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "A rising environmental concern, phosphorus (P) loss from agricultural fields via surface runoff or sub-surface drainage ends up in freshwater bodies (river, lakes), where it causes widespread algal blooms and water quality degradation. Recent studies suggest that agricultural fields fitted with artificial tile drainage system contribute heavily to these P losses. Simulation models could help to measure and manage the agricultural P losses and inform prudent management decisions to mitigate this problem in a time saving and cost-effective way. Computer simulation models for this purpose are presently lacking, particularly for tile drained agricultural fields. Accordingly, the present study was undertaken to develop a computer simulation model to simulate P loss from a tile drained agricultural field through different hydrological pathways. A state-of-the-art algorithm to simulate the fate and transport of P in tile-drained agricultural systems is proposed, tested and incorporated into the RZWQM2 model, to take advantage of its hydrologic and agricultural management subroutines — thereby yielding the RZWQM2-P model. Structured according to Jones et al., (1984) with updates and modifications prescribed by Vadas, (2014), the RZWQM2-P model features dedicated manure and fertilizer P pools to simulate P dynamics arising from their application. To simulate daily P absorption/desorption among the P pools, a dynamically changing rate factor is applied rather than a constant rate factor. Tile drainage dissolved reactive P (DRP) and particulate bound P (PP) loss are estimated according to Francesconi et al., (2016) and Jarvis et al., (1999), respectively. Losses of DRP and PP through surface runoff are simulated according to Neitsch et al., (2011) and McElroy et al., (1976), respectively. The RZWQM2-P model’s capacity to simulate the DRP and PP loss from an agricultural field through surface runoff and tile drainage was evaluated using two sets of observed P loss and water flow data collected from subsurface-drained fields under a corn-soybean rotation on a clay loam soil in southwestern Ontario, Canada. For both cases, the RZWQM2-P model performed satisfactorily (NSE > 0.50, PBAIS within ±30%, IoA >0.75). A sensitivity analysis of the RZWQM2-P’s input parameters was conducted to facilitate the application of the model by users like agricultural managers and environmental stakeholders. The sensitivity analysis found the simulation of RZWQM2-P’s P loss depends on many parameters; however, macroporosity was the preeminent parameter in simulation of all form of P losses. The DRP loss through surface runoff was most sensitive to the P extraction coefficient, and PP loss through surface runoff was mainly governed by the parameters of the Universal Soil Loss Equation. Tile flow DRP and PP losses were most sensitive to the plant P uptake distribution parameter and the soil detachability coefficient. The newly developed RZWQM2-P model is a capable tool for the simulation of P losses from an agricultural field, particularly for the tile-drained fields, however, it requires skilled and computationally demanding modelling"--
Book Synopsis Evaluating Fertilizer Application Practices to Reduce Phosphorus Discharge from the Maumee River by : Marie C. Gildow
Download or read book Evaluating Fertilizer Application Practices to Reduce Phosphorus Discharge from the Maumee River written by Marie C. Gildow and published by . This book was released on 2015 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increased soluble reactive phosphorus (SRP) discharge from agricultural watersheds is the leading cause of Lake Erie's increasingly severe harmful algal blooms (HABs) and threatens human health, ecosystem health, and economic vitality. As the largest contributor of SRP to Lake Erie, the dominantly agricultural Maumee River watershed in northwest Ohio must reduce springtime SRP load into the lake by an estimated 41% to reduce the intensity and frequency of future HABs. To achieve reductions of SRP, three nutrient management practices, (1) fertilizer placement within the soil, (2) adjusted seasonal timing of fertilizer application, and (3) adjusted date of fertilizer application to drier days have been recommended. However, no quantitative analyses have verified the actual ability of these practices to reduce phosphorus loading from the watershed. To address this critical gap in knowledge, a model of the Maumee watershed was developed to evaluate the effectiveness of these three recommended management plans to reduce SRP and total phosphorus (TP) from the Maumee River. A baseline scenario was created to accurately replicate recorded SRP and TP loading from the watershed from 1998-2012. Then, scenarios were modeled with variations of the three recommended management routines from 2007-2012, and compared to one another using statistical analysis of variance. This process determined which management plans had a statistically significant effect on SRP and TP loading, and quantified changes in SRP and TP loading to Lake Erie expected from each management practice. Overall, fertilizer placement had the greatest potential to influence SRP and TP loads. Compared to baseline levels, maximum fertilizer placement reduced spring SRP and TP loading by 42% and 27%, respectively, and annual SRP and TP loading by 46% and 29%, respectively. Seasonal fertilizer application timing also impacted spring SRP and TP loads. Under maximum adoption of spring fertilizer application, spring SRP and TP loading increased 20% and 3%, respectively, compared to baseline seasonal application in which a majority of fertilizer was applied in the fall. Changing the date of application from wetter days to drier days across the watershed did not significantly affect SRP or TP loads. These results indicate that, of the three BMPs examined, implementation of maximum fertilizer placement has the greatest potential to reduce TP and SRP runoff from the Maumee watershed. Reducing spring application of fertilizer is also an effective BMP to prevent springtime agricultural TP and SRP loss, although to a lesser degree than fertilizer placement.
Book Synopsis Drinking Water Treatment Residuals for Removal of Phosphorus in Agricultural Runoff by : Beth Kondro
Download or read book Drinking Water Treatment Residuals for Removal of Phosphorus in Agricultural Runoff written by Beth Kondro and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excess nutrient loading to the Great Lakes Basin from agricultural runoff has negatively impacted water quality, resulting in harmful algal blooms. Best management practices, including constructed wetlands and sedimentation basins, can be used to reduce phosphorus losses from agricultural fields. Constructed wetlands are efficient in the removal of particulate phosphorus; however, removal of dissolved phosphorus is limited and requires further treatment to improve surface water quality. Several types of filter media (composed of Ca, Fe, and/or Al) can be used to further reduce the amount of dissolved phosphorus that enters surface water, and a media consisting of low-cost waste residual would be beneficial to adoption. Drinking water treatment residuals (DWTR) that often contain Al could be reused as an adsorbent for dissolved phosphorus. We evaluated the use of modified drinking water treatment residuals for removing dissolved phosphorus from wastewater. DWTR were mixed with binders, made into pellets to create an insoluble media with mechanical strength, and pyrolyzed to create a reactive media pellet. Pellets were evaluated using flow through columns and included experiments to determine the impact of pH (i.e. 6, 8, and 10), retention time (i.e. 1, 5, and 10 min), and field-collected agricultural runoff on dissolved P removal. Cement was found to be the best binding material to create an insoluble pellet with mechanical strength. The P removal capacity of the pellet consisting of the cement binder (1,397 mg P/kg) was within the range of previously evaluated steel slag (120-10,210 mg P/kg), a common reactive media for P removal. The addition of drinking water treatment residual and metals decreased the P removal capacity of the cement binder at pH 6-1 min retention at exhaustion. Increasing retention time increased the P removal capacity of the filter media tested. Wastewater pH has a minimal impact on the P removal capacity of all media except the pyrolyzed DWTR + cement binder media. Evaluated media was negatively impacted by real agricultural runoff with a measured decrease in P removal capacity (43-146 mg/kg decrease) compared to P-spiked distilled water at the same retention time. The pyrolyzed cement pellet was the most cost-effective reactive media, due to an increased P removal capacity. Pyrolyzed DWTR + cement binder would be more costly than the pyrolyzed cement binder alone but could provide a solution for the disposal of DWTR.
Book Synopsis The Importance of Intra-management Practice Variability in Phosphorus and Total Solids Losses from Agricultural Fields by : Melissa Danielle Miller
Download or read book The Importance of Intra-management Practice Variability in Phosphorus and Total Solids Losses from Agricultural Fields written by Melissa Danielle Miller and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Eutrophication and sedimentation are persistent issues in the Chesapeake Bay Watershed. Best management practices (BMPs), such as no-till and shallow-disk manure injection, are promising solutions to reduce nutrient and sediment losses to water bodies. However, field studies seeking to quantify the effectiveness of shallow-disk injection as a P mitigation strategy are often constrained by hydrologic variability across spatial and temporal scales. There is an increased need to understand how BMP effectiveness is affected by site-specific conditions in order to better target BMP implementation to areas where they will be most effective. This thesis focuses on characterizing and explaining variability in total solids (TS) and phosphorus (P) losses from twelve experimental plots in central Pennsylvania (PA). The overall objective was to understand the underlying causes of variability in P and TS losses from these plots to provide greater context for understating the effectiveness of shallow-disk injection versus broadcasting. The first chapter assesses variability in the transport dynamics of dissolved P (DP), total P (TP), particulate P (PP), and TS losses from these agricultural plots. It employs load-discharge (L-Q) analyses and CVC/CVQ ratios to examine differences in transport characteristics among manure application methods and among plots of the same manure application method. Shallow-disk injection was found to be more effective than broadcasting in promoting dilution of DP, and to a lesser extent, TP. In contrast, PP showed stronger dilution patterns in broadcast plots than injection plots. There was no difference between application methods for TS. Variability among plots within each manure application practice was largely dependent on relative contributions of overland and subsurface flow. Overall, shallow-disk injection appears to be an effective practice to reduce DP and TP losses while maintaining the erosion-reducing benefits of no-till.The second chapter is focused on understanding which soil, landscape, and hydrologic characteristics play more dominant roles in driving P loss from these plots. Multiple linear regression was used to describe how manure application practices interact with soil and landscape characteristics and predict overland and subsurface P exports. On average, injection plots exported 65% less DP and 48% less TP in overland flow and 81% less DP and 51% less TP in subsurface flow, with almost no differences in PP exports. The multiplicative effects of flow and Mehlich-3 P were the most effective predictors of P losses via both overland and subsurface flow, and unstratified (0-15 cm) measures of Mehlich-3 P concentrations were more or as effective as stratified (0-5 cm and 5-15 cm) concentrations in predicting losses in overland flow. While, soil and landscape characteristics, like soil texture and curvature, often provided additional predictive power. The results of this analysis revealed that shallow-disk injection is effective in reducing P losses and may be effective in preventing P build-up in soils without prior history of manure application.These two studies highlight the importance of understanding site hydrology and management practices as primary drivers of P losses from agricultural fields. Extensively monitored plots such as these provide a unique opportunity to study the effects of BMPs, such as shallow-disk injection, on a small scale, allowing for the assessment of variability among individual units. This work suggests that shallow-disk injection is an effective practice to reduce DP losses by reducing P source availability on the soil surface but does not exacerbate PP losses.
Book Synopsis Field-scale Nutrient Transport Monitoring and Modeling of Subsurface and Naturally Drained Agricultural Lands by : Mark Eastman
Download or read book Field-scale Nutrient Transport Monitoring and Modeling of Subsurface and Naturally Drained Agricultural Lands written by Mark Eastman and published by . This book was released on 2008 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Agricultural Nonpoint Source Control of Phosphorus in the New York State Lake Ontario Basin: The influence of tillage on phosphorus losses from manured cropland by :
Download or read book Agricultural Nonpoint Source Control of Phosphorus in the New York State Lake Ontario Basin: The influence of tillage on phosphorus losses from manured cropland written by and published by . This book was released on 1991 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Water Residuals to Reduce Soil Phosphorus by : J. DeWolfe
Download or read book Water Residuals to Reduce Soil Phosphorus written by J. DeWolfe and published by IWA Publishing. This book was released on 2006-06-30 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phosphorus in surface runoff from agricultural lands is often implicated in the degradation of surface water quality. Many states are developing soil phosphorus application limits. Utilities must develop and implement new best management practices (BMPs) to control phosphorous. The objective of this project was to investigate the beneficial use of water treatment residuals (WTRs) to control non-point source (NPS) phosphorus pollution and protect surface water quality. Specifically, the researchers planned to examine the unique chemical characteristics of WTRs, namely the large concentration of aluminum and iron hyrdroxides, to combine them with phosphorus in high phosphorus soils, biosolids, and manures to reduce the likelihood of phosphorus release to aquatic environments. Several types of WTRs were selected and characterized based on the coagulant used (aluminum and iron based) and their form - dewatered or liquid. The research developed valuable new insight for the beneficial use of WTRs and demonstrated WTRs' potential as a BMP for phosphorus control in surface runoff from agricultural lands and for protecting surface water quality. In particular, the potential role of WTRs in Phosphorous Index programs was confirmed. Future research and full-scale demonstrations are needed to confirm the potential of land applied WTRs as a BMP for phosphorus control in runoff from agricultural lands. Land application of WTRs within a utility?s source water watershed, while subject to local and state regulations, can be implemented as part of an overall watershed protection program.
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.
Book Synopsis Identification of High Phosphorus Loss Areas in Agricultural Watersheds by : Katie Songer
Download or read book Identification of High Phosphorus Loss Areas in Agricultural Watersheds written by Katie Songer and published by . This book was released on 2009 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Improving Phosphorus Loss Assessment with the Apex Model and Phosphorus Index by : Ammar B. Bhandari
Download or read book Improving Phosphorus Loss Assessment with the Apex Model and Phosphorus Index written by Ammar B. Bhandari and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Agricultural fields contribute phosphorus (P) to water bodies, which can degrade water quality. The P index (PI) is a tool to assess the risk of P-loss from agricultural fields. However, due to limited measured data, P indices have not been rigorously evaluated. The Agricultural Policy/Environmental Extender (APEX) model could be used to generate P-loss datasets for P index evaluation and revision. The objectives of the study were to i) determine effects of APEX calibration practices on P-loss estimates from diverse management systems, ii) determine fertilizer and poultry litter management effects on P-loss, iii) evaluate and update the Kansas PI using P-loss simulated by APEX and iv) determine appropriate adsorption isotherms with advection-dispersion equation with column leaching experiment. Runoff data from field studies in Franklin and Crawford counties were used to calibrate and validate APEX. Poultry litter and inorganic fertilizer application timing, rate, method, and soil test P concentration effects on P loss were analyzed using location-specific models. A column leaching laboratory study was also conducted to test the adsorption isotherms. Location-specific model satisfactorily simulated runoff, total P (TP) and dissolved P (DP) loss meeting minimum model performance criteria for 2/3 of the tests whereas management-specific models only met the criteria in 1/3 of the tests. Applying manure or fertilizer during late fall resulted in relatively lower TP loss compared to spring applications before planting. The Kansas-PI rating and the APEX simulated P-loss were correlated with r2 of 0.40 (p
Book Synopsis Characterizing Dissolved Phosphorus Transport Through Vegetated Filter Strips by : Jennifer Gilbert
Download or read book Characterizing Dissolved Phosphorus Transport Through Vegetated Filter Strips written by Jennifer Gilbert and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonpoint phosphorus (P) pollution of surface and shallow groundwater is a global environmental problem, particularly in regions where animal agriculture is concentrated. In the Coastal Plain region of Delaware, over application of manures and P fertilizers have saturated soils with respect to P. One practice commonly recommended by advisory agencies to control nonpoint source (NPS) P loss from agricultural land is the vegetated filter strip (VFS). Vegetative filter strip effectiveness at mitigating NPS P pollution is usually based on quantity of stormwater infiltrated and sediment settled out of the water column. When soils are saturated with respect to P, VFS effectiveness at preventing dissolved P losses by enhancing infiltration and retaining dissolved P moving laterally through subsoil is less certain. It is therefore the goal of this research to address three key P management questions. First (Chapter 2) is to determine methods to increase soil P sorption capacity that can be included in VFS design, based on processes that control P sorption in the acid sandy Mid Atlantic Coastal Plain soils. Second (Chapter 3), is to monitor dissolved and total P flow in surface runoff and groundwater flow through VFS to determine the relative importance, and mechanisms of dissolved P transport relative to total P. Data from this study will be used both to determine how VFS function in the Coastal Plain landscape, as well as to validate the P components of the Riparian Ecosystem Management Model (REMM). Finally, in Chapter 4 the P components of REMM will be validated for use in the Mid-Atlantic Coastal Plain region. Eight Conservation Reserve Enhancement Program VFS were selected for evaluation, representing the major agricultural soils and variability in VFS design observed throughout Delaware. Soils were collected from VFS and adjacent agricultural fields at three depths, 0-15, 15-30, and 30-45 cm, and were characterized by routine analysis of the University of Delaware soil testing lab, as well as for soil adsorption/desorption properties. Deep tillage of the soil profile was then simulated by mixing equal portions of 0-15, 15-30, and 30-45 cm depth soils, and mixed soils were analyzed for P sorption characteristics. VFS establishment had little effect on the soil P source component of P loss, including soil test P (Mehlich-3 P, M3) and soil P saturation (measured as the M3-P saturation ratio, PSR) relative to adjacent agricultural fields. Simulated deep tillage of VFS soils to 45 cm decreased M3-P in mixed soils as much as 62%, compared to M3-P at the 0-15 cm soil depth, and achieved maximum soil PSR reductions of 70% as compared to 0-15 cm soil prior to mixing. Vegetated Filter Strips were then established in two fields at the University of Delaware Research and Education Center, in Georgetown, DE. VFS in each field were further split into two plots, one deep tilled using a chisel plow and the other disk tilled prior to planting. Groundwater wells were installed and groundwater samples were collected weekly. Surface runoff was collected within 24 hours of each storm event. Water samples were analyzed for total P (TP), dissolved reactive P (DRP) nitrate (NO 3 - -N) and ammonia (NH 4 + -N). Chisel plowing was not effective at redistributing P from surface soils through the soil profile. Average surface runoff P concentrations (TP and DRP) were as much as an order of magnitude greater than groundwater P. Groundwater P concentration spiked shortly after storm events, and then quickly declined to background levels, though groundwater DRP concentration was rarely less than 0.1 mg P L -1 . Phosphorus sorption and desorption equations were modified in REMM to reflect properties important to acid sandy Coastal Plain soils. Based on strong coefficients of determination, changing these equations would be expected to improve prediction of P transport through vegetated filter strips. Simulation data were significantly different from measured data, though simulated and measured data were similar with respect to environmental relevance. Vegetated filter strips are an important practice to mitigate agricultural NPS pollution. In P saturated soils, dissolved P transport in subsurface flow remains an environmental concern. Further evaluation of methods to thoroughly mix the soil profile prior to planting should be investigated to improve retention of dissolved P by VFS. Models such as REMM can be helpful in designing VFS and improving placement within the Coastal Plain Landscape.
