Author: Yvonne E. SalladePublisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
Characterization and Potential for Phosphorus Release of Agricultural Drainage Ditch Sediments in Delaware's Inland Bays' Watershed
Author: Yvonne E. SalladeCharacterization of Subsurface Phosphorus Loss in Artificially-drained Fields on the Delmarva Peninsula
Author: Kathryn Louise ClarkPublisher:
ISBN: 9781369353624
Category :
Languages : en
Pages : 104
Book Description
Long-term applications of broiler manure to Delmarva agricultural soils at rates that exceed crop uptake led to the buildup of phosphorus (P) in soils to concentrations that exceed agronomic optimum. This legacy soil P is at risk for losses through artificial drainage systems that are installed to allow agricultural production of soils with high water tables and drainage problems throughout the Delmarva region. Transport of P through artificial drainage systems to sensitive waterbodies like the Chesapeake Bay and Delaware Inland Bays is an important pathway for P losses from agriculture on Delmarva. However, knowledge about the mechanism and frequency of subsurface P transport events remains limited. The objectives of this study were to: 1) develop a method for using geophysics to study subsurface flowpaths in an agricultural field; 2) better understand how P interacts with subsurface hydrology, as applied at a small field site at the University of Maryland, Eastern Shore research farm; 3) determine how subsurface P loss risk is accounted for in several P indices used for artificially drained fields; and 4) determine recommended risk factors for inclusion in a future version of the Delaware Phosphorus Site Index. Electrical Resistivity Imaging (ERI) and a bromide (Br) salt tracer were used at the University of Maryland Eastern Shore research farm to better understand subsurface water flows and potential for P loss in subsurface lateral flow. Electrical resistivity was monitored in real time during two storm events (October 2015 and February 2016) following application of a Br tracer within a trench located within the larger ERI monitoring grid (7 m x 12.5 m). The ERI visualization revealed the presence of tracer within and slightly below the trench (possible density dependent flow); however, minimal lateral movement was seen likely due to the low intensity of the storm events. Continued monitoring during heavier storm events at this site is recommended. Additionally, better corroboration of ERI data with both hydrologic and visual monitoring is critically needed. Phosphorus indices are field-based management tools used to identify fields with a high risk of P transport due to both site hydrology and presence of P sources. The P index is also an important tool to guide mitigation of P losses by incentivizing best management practices (BMPs). Subsurface P losses are often poorly accounted for in P indices due to lack of understanding of these processes. We compared regional (Delaware, Maryland, Virginia, and North Carolina) P index approaches to address the risk of subsurface P loss in the subsurface. Five P indices were calculated for conditions based on collected deep (approximately 1 m) soil cores collected from 13 field sites throughout the Delmarva. Overall P index scores and risk ratings were compared among indices as calculated for individual core samples at each site. In addition, calculated subsurface P risk scores were compared to concentrations of water extractable and Mehlich 3 P in soil near the estimated seasonal high water table. Based on comparisons of P Index score to field scenarios, the Delaware P Site Index and updated version of the University of Maryland P Management Tool (PMT2) most accurately predicted the overall P loss risk determined for various scenarios. However, the University of Maryland P Management tools (UM-PMT and PMT2) and Virginia P Index most accurately predicted the risk for subsurface P losses (based on soil P concentrations near the seasonal high water table). We recommend that future updates to Delaware’s PSI account for risk of both leaching potential and subsurface lateral flow potential by taking into account the following factors: soil P saturation ratio, calculated runoff and percolation volume, hydrologic soil group, soil drainage class, and drainage intensity. Updated P Indices should be evaluated using measured and modeled water quality data.
An Analysis of Nutrient Utilization Efficiency by Agriculture in Delaware's Inland Bays Drainage Basin
Author: John Hall MartinPublisher:
ISBN:
Category : Agricultural pollution
Languages : en
Pages : 92
Book Description
Agronomy Abstracts
Author: Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 976
Book Description
Includes abstracts of the annual meetings of the American Society of Agronomy; Soil Science Society of America; Crop Science Society of America ( - of its Agronomic Education Division).
Tracking Sources of Particulate Phosphorus in River Waters
Author: Kristi BearPublisher:
ISBN: 9781369353365
Category :
Languages : en
Pages : 84
Book Description
Incomplete understanding of phosphorus (P) forms and their recalcitrance under imposed environments coupled with methodological limitations to track P sources are obstacles preventing accurate assessment of nutrient loads released to open waters. In this thesis research, the East Creek Watershed in Crisfield, MD, an agricultural runoff dominated watershed, was selected to understand the fate and stability of P from various sources during transport from East Creek to the Chesapeake Bay. To achieve this, P concentrations and phosphate oxygen isotope ratios were compared between sequentially extracted Hedley P pools from potential sources and suspended particulate matter. A transect study from an agricultural field to a drainage ditch was also conducted to identify potential P release pathways. Transect study results suggested soil erosion is a plausible P source to ditch sediments after crop harvest, although dissolved P was the prominent P form in the ditch water column during summer algal blooms which drive sedimentary P release. Comparative analyses of P pools in suspended particulate matter in creek water suggest that particulate P is primarily carried in loosely sorbed and Fe/Al oxide-bound forms. Isotope results suggest loosely sorbed P is bioavailable whereas Fe/Al oxide-bound P and Ca-P precipitates were not accessed by microbes during particulate P transport through the creek. Agricultural field soil, streambank material, and sediments were important sources of legacy P, although mechanism of P release and contribution differed among them. These findings improve understanding on sources and fate of particulate P and are expected to be useful for nutrient management in soils and waterways.
Phosphorus Release from Lake Sediments
Author: Raymond E. WildungPublisher:
ISBN:
Category : Eutrophication
Languages : en
Pages : 218
Book Description
Proceedings of the Third International Workshop on Phosphorus in Sediments
Author: P.C.M. BoersPublisher: Springer Science & Business Media
ISBN: 9401115982
Category : Science
Languages : en
Pages : 382
Book Description
This Workshop was organized to assess the status of knowledge on the behaviour of phosphorus in sediments and to define gaps and reassess research strategies, particularly with respect to prevalent methodology and future approach; and to define gaps and reassess research strategies for water management measures in aquatic ecosystems, especially in relation to the release of phosphorus from the sediments and its impact on the functioning of the whole system.
Soils and Fertilizers
Author: Development, Calibration, and Analysis of a Hydrologic and Water-quality Model of the Delaware Inland Bays Watershed
Author: Angélica L. Gutiérrez-MagnessPublisher:
ISBN:
Category : Bays
Languages : en
Pages : 56
Book Description
Characterization of Cuyahoga River Sediments
Author: Kurt Walter WhitfordPublisher:
ISBN:
Category : Phosphorus
Languages : en
Pages : 162
Book Description