Filters: Tags: nitrates (X)
10 results (125ms)|
Filters
Date Range
Extensions Types Contacts
Categories Tag Types
|
Using a model as a management tool requires testing of the model against field-measured data prior to its application for solving natural resource problems. This study was conducted to test the Root Zone Water Quality Model (RZWQM98) using four years (1996 to 1999) of field-measured data to simulate the effects of different N-application rates on corn yields and nitrate-nitrogen (NO[3]-N) losses via subsurface drain water. Three N-application rates (low, medium, and high), each replicated three times, were applied to corn in 1996 and 1998 under a randomized complete block design at a tile-drained corn-soybean rotation field near Story City, Iowa. No N-fertilizer was applied to soybean in 1997 and 1999. Model calibration...
Categories: Publication;
Types: Citation;
Tags: Data Visualization & Tools,
Dose activity relation,
Drainage water,
Eau drainage,
Fertilisation Soil pollution,
The relationship between local ground water flows and NO(3)(-) transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO(3)(-) concentrations decreased from approximately 3 mg N L(-1) beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L(-1) at wells 1 to 3 m from the channel. The Cl(-) concentrations and NO(3)/Cl ratios decreased toward the channel indicating NO(3)(-) dilution and biotic retention. In the bankside well transect parallel to the stream,...
Categories: Publication;
Types: Citation;
Tags: Agriculture,
Carbon,
Environmental Monitoring,
Minnesota,
Nitrates,
The relationship between local ground water flows and NO(3)(-) transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO(3)(-) concentrations decreased from approximately 3 mg N L(-1) beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L(-1) at wells 1 to 3 m from the channel. The Cl(-) concentrations and NO(3)/Cl ratios decreased toward the channel indicating NO(3)(-) dilution and biotic retention. In the bankside well transect parallel to the stream,...
Categories: Publication;
Types: Citation;
Tags: Agriculture,
Carbon,
Environmental Monitoring,
Minnesota,
Nitrates,
Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO(3)(-)) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO(3)(-) to determine the dominant sources and processes that affect NO(3)(-) concentrations in six stream/river watersheds of different land uses. Samples were collected monthly at a range of flow conditions for 15 mo during 2004-05 and analyzed for NO(3)(-) concentrations, delta(15)N(NO3), and delta(18)O(NO3). Samples from two forested watersheds indicated that NO(3)(-) derived from nitrification was dominant at baseflow. A watershed dominated by suburban land use had three delta(18)O(NO3)...
Categories: Publication;
Types: Citation;
Tags: Agriculture,
Fresh Water,
New York,
Nitrates,
Nitrogen
This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. Records include attributes such as commodity, country, location, company name, facility type and capacity if applicable, and generalized coordinates. The data were compiled from multiple sources, including the 2003 and 2004 USGS Minerals Yearbooks (Latin America and Candada volume), data to be published in the 2005 Minerals Yearbook Latin America and Canada Volume, minerals statistics and information from the USGS minerals...
Atmospheric particulate matter (PM) is a heterogeneous material. Though regulated as un-speciated mass, it exerts most effects on vegetation and ecosystems by virtue of the mass loading of its chemical constituents. As this varies temporally and spatially, prediction of regional impacts remains difficult. Deposition of PM to vegetated surfaces depends on the size distribution of the particles and, to a lesser extent, on the chemistry. However, chemical loading of an ecosystem may be determined by the size distribution as different constituents dominate different size fractions. Coating with dust may cause abrasion and radiative heating, and may reduce the photosynthetically active photon flux reaching the photosynthetic...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Biodiversity,
Deposition mode,
Ecosystem response,
Environment International,
Heavy metals,
Agriculture is the leading source of nonpoint-source pollution on a national scale. the driving force of nonpoint-source pollution is the rainfall-runoff process, which is the transformation of rainfall to streamflow. This is a complex, nonlinear, time-varying, and spatially distributed process on the watershed scale that is difficult to effectively model by conventional, deterministic means. Artificial neural networks (ANNs) offer a new approach to forecasting the hydrologic and water quality response of a watershed system. The goal of this work is to develop an ANN model as a long-term forecuating tool for predicting the hydrology and water quality of agricultural watersheds where the physical processes are difficult...
Categories: Publication;
Types: Citation;
Tags: Agriculture,
Artificial neural network,
Data Visualization & Tools,
Engineering,
Hydrology,
This dataset is a summary, by HUC6, of potential and known threats to the quality of groundwater. This dataset is part of a larger groundwater project across the Pacific NW (Brown et al. 2009) region which has two primary goals: (1) develop tools to identify where and how groundwater is important to biodiversity conservation and (2) assess the pressing threats to the quantity and quality of that groundwater and develop strategies to abate those threats. Data and analyses conducted are intended for use at a statewide scale. Therefore, more detailed mapping may be necessary at local scales. For more information please contact the Oregon Field Office of The Nature Conservancy or see the following website http://www.waconservation.org....
The Nooksack River watershed comprises the majority of the Water Resources Inventory Area 1 (WRIA 1) located in Whatcom County in Washington State. From its headwaters in the northwestern Cascade Mountains, the Nooksack River drains approximately 809 square miles, comprising most of western Whatcom County, including agricultural areas and the developed lowlands surrounding the towns of Deming, Everson, Lynden, and Ferndale. The Nooksack River enters the Lummi Indian Reservation at its eastern extent, which contains the majority of the Nooksack River delta before it discharges into the marine waters of Bellingham Bay. The Nooksack River is also the primary source of freshwater into Portage Bay, which is located approximately...
Categories: Data;
Tags: Environmental Health,
USGS Science Data Catalog (SDC),
Water Quality,
Water Resources,
biota,
This dataset is composed of 6th-field Hydrologic Units (HUC6 watersheds) in Washington State. Attributes describe the presence or absence of threats to groundwater quality in each HUC. Threats include: 1.) known groundwater contamination by nutrients, pesticides, or industrial chemicals; 2.) indicators of nutrient threats (including agricultural and urban fertilizers, septic systems, Underground Injection Control (UIC) sites associated with nutrients, and Confined Animal Feeding Operations (CAFOs); 3.) indicators of pesticide threats (agricultural and urban pesticide use); and 4.) indicators of industrial contaminant threats (including UICs associated with chemical contaminants, hazardous waste spill sites, Leaking...
|
|
