نتایج جستجو برای: nitrogen budget

تعداد نتایج: 152552  

2008
Sara K. Enders Mark Pagani Silvio Pantoja Jill S. Baron Alexander P. Wolfe Nikolai Pedentchouk Lilian Nuñez

Compound-specific nitrogen, carbon, and hydrogen isotope records from sediments of Sky Pond, an alpine lake in Rocky Mountain National Park (Colorado, United States of America), were used to evaluate factors contributing to changes in diatom assemblages and bulk organic nitrogen isotope records identified in lake sediments across Colorado, Wyoming, and southern Montana. Nitrogen isotopic record...

2002
ROBERT E. DICKINSON JOSEPH A. BERRY GORDON B. BONAN G. JAMES COLLATZ CHRISTOPHER B. FIELD INEZ Y. FUNG MICHAEL GOULDEN WILLIAM A. HOFFMANN ROBERT B. JACKSON RANGA MYNENI PIERS J. SELLERS MUHAMMAD SHAIKH

Most evapotranspiration over land occurs through vegetation. The fraction of net radiation balanced by evapotranspiration depends on stomatal controls. Stomates transpire water for the leaf to assimilate carbon, depending on the canopy carbon demand, and on root uptake, if it is limiting. Canopy carbon demand in turn depends on the balancing between visible photon-driven and enzyme-driven steps...

2014
R. Singh Arun Kumar

The continuous evolvement of dairy industry in countries like New Zealand, with increased dairy conversions and intensification, has resulted in remarkable economic development, though at the cost of environmental degradation. The increasing use of nitrogen fertilizers to sustain increasing number of cows has increased the risk of enhanced nitrate leaching and methane and nitrous oxide emission...

2004
Curtis Deutsch Daniel M. Sigman Robert C. Thunell Anna Nele Meckler Gerald H. Haug

[1] We investigate the response of the N/N of oceanic nitrate to glacial/interglacial changes in the N budget, using a geochemical box model of the oceanic N cycle that includes N2 fixation and denitrification in the sediments and suboxic water column. This model allows us to quantify the isotopic response of different oceanic nitrate pools to deglacial increases in water column and sedimentary...

Journal: :Ecological applications : a publication of the Ecological Society of America 2006
Mark B David Lareina G Wall Todd V Royer Jennifer L Tank

Denitrification is an important process in aquatic sediments, but its role has not been assessed in the N mass balance of upper-Midwestern (USA) reservoirs that receive large agricultural riverine N inputs. We used a 4400-ha reservoir to determine the role of denitrification in the N mass balance and effectiveness in reducing downstream transport of NO(3-)N. Sediment denitrification was (1) mea...

2015
Emilie R. Kirk Chris van Kessel William R. Horwath Bruce A. Linquist

Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Ory...

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