نتایج جستجو برای: phosphorus and nitrogen

تعداد نتایج: 16851642  

Bijan Bina Hossein Movahedian Mahnaz Nikaeen Majid Kermani, Mohammad Mehdi Amin

In this research, an experimental study to evaluate nutrient removal from synthetic wastewater by a lab-scale moving bed biofilm process was investigated. Also, kinetic analysis of the process with regard to phosphorus and nitrogen removal was studied with different mathematical models. For nutrient removal, the moving bed biofilm process was applied in series with anaerobic, anoxic and aerobic...

2000
Claire L. Schelske Edward D. Rothman Eugene F. Stoermer Mila A. Santiago

Factorial nutrient enrichment expcrimcnts were conducted with water containing natural phytoplankton assemblages collected from Grand Traverse Bay. Levels of phosphorus (phosphate) were 5, 15, 25, 40, and 60 pg P liter4 and levels of nitrogen (nitrate) were 0.23, 0.84, and 1.12 mg N liter-l. Nutrients were maintained at these levels by additions at 2or S-day intervals. Two different analyses of...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
David W Schindler R E Hecky D L Findlay M P Stainton B R Parker M J Paterson K G Beaty M Lyng S E M Kasian

Lake 227, a small lake in the Precambrian Shield at the Experimental Lakes Area (ELA), has been fertilized for 37 years with constant annual inputs of phosphorus and decreasing inputs of nitrogen to test the theory that controlling nitrogen inputs can control eutrophication. For the final 16 years (1990-2005), the lake was fertilized with phosphorus alone. Reducing nitrogen inputs increasingly ...

Akbar Talebzadeh Keyvan Marashi,

BACKGROUND: Soil nutrition management is an important factor, which determines the plant growth. Soil fertility is determined by the presence or absence of nutrients i.e. macro and micronutrients, which are required in optimum level for crop. OBJECTIVES: Evaluate the effect different amount of nitrogen and phosphorus fertilizers in maize field under sugarcane ...

Journal: :archives of hygiene sciences 0
mojgan mirzaei department of environmental sciences, malayer university, malayer, hamedan, iran. eisa solgi department of environmental sciences, malayer university, malayer, hamedan, iran. abdolrassoul salman mahiny gorgan university of agriculture sciences and natural resources, environmental sciences, college of fisheries and environmental sciences. gorgan, iran.

background & aims of the study: in this research, long-term hydrologic impact assessment model is selected for simulation of runoff and nps pollution. the aim of this study is modeling of non-point source pollution by l-thia model in zayandehrood watershed in 2015. materials & methods: in this study, analytical survey and investigation of references in the context of library studies has been us...

Journal: :علوم گیاهان زراعی ایران 0
رقیه محمدپوروشوایی دانشجوی کارشناسی ارشد آگرواکولوژی، گروه زراعت، دانشکدة کشاورزی، دانشگاه زابل احمد قنبری استاد زراعت، گروه زراعت، دانشکدة کشاورزی، دانشگاه زابل براتعلی فاخری دانشیار اصلاح نباتات، گروه اصلاح نباتات و بیوتکنولوژی، دانشکدة کشاورزی، دانشگاه زابل

to evaluate the effect of chemical and bio-fertilizer on nitrogen, phosphorus and potash concentration, biochemical traits and calyxes yield of roselle, an experiment was conducted in the split plot based on randomized coplete block design with three replications, at the research station in zabol university, during 2013 and 2014. the main plot consisted of three levels: phosphorus, nitrogen and...

2010
Matthew M. Mills Kevin R. Arrigo

The elemental stoichiometry of sea water and particulate organic matter is remarkably similar. This observation led Redfield to hypothesize that the oceanic ratio of nitrate to phosphate is controlled by the remineralization of phytoplankton biomass1. The Redfield ratio is used universally to quantitatively link the marine nitrogen and phosphorus cycles in numerous biogeochemical applications2–...

Abdolali Gilani, Kamran Mohsenifar, Morteza Mohamadi

BACKGROUND: One of limitation factor in agricultural plants production in dry areas, supply requires water. Also nutrition crop management is a necessary strategy for achieve sustainable agriculture. OBJECTIVES: Current study was conducted to assessment the effects of different irrigation regimes and several amount of nitrogen fertilizer on seed nutrition...

Journal: :international journal of environmental research 2011
h. li y. wang l.q. shi j. mi d. song

dianchi lake is one of the most three seriously eutrophic lakes in china. in the present study, the phosphorus (p) and nitrogen (n) fractions in 37 surface sediments samples collected in the dianchi lake were investigated. the total phophorus (tp) in sediments was divided into two parts: inorganic p (ip) and residual p (res-p). the results showed that the total phosphorus content in surface se...

Journal: :international journal of environmental research 0
y. wang faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china y. wang faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china l.q. shi faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china d. song faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china d. song faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china x.j. pan faculty of environment science and engineering, kunming university of science and technology, kunming, yunnan 650093, p. r. china

dianchi lake is one of the most three seriously eutrophic lakes in china. in the present study, the phosphorus (p) and nitrogen (n) fractions in 37 surface sediments samples collected in the dianchi lake were investigated. the total phophorus (tp) in sediments was divided into two parts: inorganic p (ip) and residual p (res-p). the results showed that the total phosphorus content in surface sed...

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