نتایج جستجو برای: n no3

تعداد نتایج: 980748  

2014
Xingliang Xu Qingkang Li Jingyuan Wang Leiming Zhang Shengni Tian Lin Zhi Qianru Li Yue Sun

The fern Dicranopteris dichotoma is an important pioneer species of the understory in Masson pine (Pinus massoniana) forests growing on acidic soils in the subtropical and tropical China. To improve our understanding of the role of D. dichotoma in nitrogen (N) uptake of these forests, a short-term (15)N experiment was conducted at mountain ridge (MR, with low N level) and mountain foot (MF, wit...

2000
R. J. PARKINSON P. GRIFFITHS A. L. HEATHWAITE

A field experiment was conducted on a sloping grassland soil in southwest England to investigate the downslope transport of nitrogen in soil water following the application of cattle manure, slurry and inorganic fertilizer. Transport of nitrogen (N) species was monitored on hydrologically isolated plots. Manure (50 t ha"), slurry (50 m ha") and fertilizer (250 kg N ha") were applied in February...

Journal: :Journal of environmental quality 2009
Douglas A Burns Elizabeth W Boyer Emily M Elliott Carol Kendall

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 c...

2005
MARI ITO MYRON. J. MITCHELL CHARLES T. DRISCOLL KAREN M. ROY

The Adirondack region of New York is characterized by soils and surface waters that are sensitive to inputs of strong acids, receiving among the highest rates of atmospheric nitrogen (N) deposition in the United States. Atmospheric N deposition to Adirondack ecosystems may contribute to the acidification of soils through losses of exchangeable basic cations and the acidification of surface wate...

2016
Jay D. Jabro William B. Stevens William M. Iversen Brett L. Allen Upendra M. Sainju

Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitratenitrogen (NO3-N) in surface and ground waters. This study evaluated the effect of conventional tillage (CT) and strip tillage (ST) practices and three N application rates on NO3-N concentrations in soil water at a 76 cm depth under ir...

2014
Yangquanwei Zhong Weiming Yan Juan Chen Zhouping Shangguan

Wheat is one of the most important food crops in the world, its availability affects global food security. In this study, we investigated variations in NH4(+) and NO3(-) fluxes in the fine roots of wheat using a scanning ion-selective electrode technique in the presence of different nitrogen (N) forms, N concentrations, and pH levels as well as under water stress. Our results show that the fine...

2010
GEORGE M CHESCHEIR SHIYING TIAN MOHAMED A YOUSSEF DEVENDRA M. AMATYA

Nutrient loading in drainage outflow is estimated from measured flows and nutrient concentrations in the drainage water. The loading function is ideally continuous, representing the product of continuously measured outflows and nutrient concentrations in drainage water. However, loading is often estimated as the product of continuously measured outflow and nutrient concentrations measured at le...

2016
Chiara Piccini Claudia Di Bene Roberta Farina Bruno Pennelli Rosario Napoli

In intensive agriculture, N supply often exceeds crop requirements, even in nitrate vulnerable zones (NVZ). In farmland, the N surplus gives rise to NO3 ́ leaching and consequent groundwater pollution. The present study aimed at proposing measures to reduce N leaching and hence improve N efficiency in a buffalo livestock farm located in the NVZ of Latina plain (Central Italy). The farm was culti...

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