Large amounts of nitrogen are stored in the soils of agricultural areas in Nebraska and Maryland, according to a new study by the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture (USDA). Once in the soil, nitrogen can be converted to nitrate, which can readily move to groundwater.
"We expected to find nitrogen stored in organic matter in these soils, but didn't realize how much," said Tom Nolan, USGS hydrologist, who led the study. "If mobilized, the large reservoirs of nitrogen could significantly impact water quality."
Nitrogen occurs in soil, plants, and groundwater, and it is difficult to account for all of the various forms it can take. For this study, scientists at the USGS National Water Quality Assessment Program and the USDA Agricultural Research Service used a new version of the Root Zone Water Quality Model to estimate unsaturated zone nitrogen mass balances at four agricultural fields. The study was reported in the May/June 2010 edition of the Journal of Environmental Quality, published by the American Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America.
The mass balances were expected to reveal the predominant forms of nitrogen in important agricultural settings. The four sites had variable climate, soils, and management practices, and included: an almond orchard in central California; a cornfield that is about 0.6 kilometers from the almond orchard; a corn–soybean crop rotation in eastern Nebraska; and a corn–soybean rotation in eastern Maryland.
The model predicted that large amounts of organic nitrogen are stored in the soil beneath fields in Nebraska and Maryland on which corn and soybean crops are grown. The model also showed that nitrogen came primarily from inorganic fertilizer or from nitrogen fixation by soybeans, and that most nitrogen was removed from the soil through uptake by crops. After crop uptake, leaching accounted for most of the nitrogen lost from the soil, particularly in irrigated areas of California. Denitrification, a process where nitrogen is removed from the soil when it is converted to its gaseous phase, occurred only sporadically at the four sites because soils generally were sandy and well-drained.
The work is novel in that the model was autocalibrated to measured data comprising soil moisture, soil water tension, bromide and nitrate concentrations, and soil organic matter. Also, previous versions of the model were limited to the rooting depth of plants (typically three meters or less). The new version of the model can make predictions down to 30 meters, enabling estimation of water quality effects well beyond the root zone. More study is needed to better understand the conditions required to mobilize and transport the stored nitrogen to groundwater.
The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://www.agronomy.org/files/publications/jeq/abstracts/39-3/q09-0310-abstract.pdf.
The Journal of Environmental Quality, http://jeq.scijournals.org is a peer-reviewed, international Journal of Environmental Quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA). The Journal of Environmental Quality covers various aspects of anthropogenic impacts on the environment, including terrestrial, atmospheric, and aquatic systems.
The American Society of Agronomy (ASA) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.
Sara Uttech | EurekAlert!
Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country
New data unearths pesticide peril in beehives
21.04.2017 | Cornell University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy