Nitrogen:phosphorus ratio

A dinuclear compound, (Me2N)3P=N-P(=NH)(NMe2)2, with a high nitrogen phosphorus ratio is the first member of a series of strongly basic, branched polyamino-imino phosphazenes (Scheme 43). ... 

Tezuka, Y. (1990) Bacterial regeneration of ammonium and phosphate as affected by the carbon nitrogen phosphorus ratio of organic substrates. Microbial Ecology 1 9, 227-238. 

Many contaminants contain nitrogen, phosphorus, or sulfur, and degradative organisms may utilize one or more of these leaving the major part of the substrate intact. This is particularly important for munitions-related compounds with a high N/C ratio, when the addition of carbon sources may lead to the favorable development of anaerobic or facultatively anaerobic microorganisms. 

It was decided to study the system tetrakis (trifluorophosphine) nickel- (0) -ammonia (23) in some detail a smooth reaction was observed when the complex, condensed on excess ammonia at liquid air temperature, was allowed to warm up gradually. Precipitation of colorless crystals, identified as ammonium fluoride in almost stoichiometric amount, based on complete ammonolysis of the phosphorus-fluorine bonds, was observed at temperatures as low as —90° to —80°. Removal of the ammonium fluoride by filtration at temperatures not higher than —50°, and subsequent slow evaporation of the ammonia from the filtrate invariably led to a brown-yellow solid, although a colorless, crystalline material was formed initially. The product was decomposed almost instantaneously by water with precipitation of elemental nickel. Analysis of the hydrolyzate obtained in aqueous hydrochloric acid revealed a nickel-phosphorus-nitrogen atom ratio close to 1 4 4, corresponding to an apparently polymeric condensation product. 

Phosphorus containing fertilizers Phosphates are the basic substances in these fertilizers. Phosphorus is also essential for plants. Phosphorus compounds are produced by powdering rock phosphate and adding sulfuric acid to it. The resulting products - phosphoric acid and calcium salts (from the rock) are directly applied to the soil to increase its phosphorus content. Potassium fertilizers examples Potassium chloride, Potassium nitrate etc. A complete fertilizer contains nitrogen, phosphorus and potassium in a fixed ratio. This is called NPK fertilizer. 

TABLE 15.1 Nitrogen and Phosphorus Ratios, Maryland Coastal Area Organic N, NH3-N, NOj-N, NO3-N, Total N, Total P, ... 

Smith, V. H. (1983). Low nitrogen to phosphorus ratios favor dominance by blue-green algae in lake phytoplankton. Science 221, 669-671. 

Studies have shown that adding bioenhancement agents to oil spilled on land can enhance the removal rate of the saturate and some of the aromatic fraction of the oil, so that as much as 40% of the oil is degraded in time periods from one month to a year. It has been found that the agents are most effective when added at an oil-to-nitrogen-to-phosphorus ratio of 100 10 1. Fertilizers that maintain the soil at a more neutral level are best for degrading oil. Fertilizers that make the soil acidic usually slow biodegradation. Fertilizers that are more oil-soluble and less water-soluble are most effective as they are not as likely to be washed away. 

We focus on temperate shelf seas because these are not only best studied, but also most subject to anthropogenic influence. Most of our examples are taken from studies in northwest European waters, because it is these that we know best. The aim of this chapter is to review recent improvements in knowledge of the sources and sinks of nutrients in the shelf seas of northwest Europe, and to consider, especially, the influence of ratios of nutrient elements on the floristic composition of the phytoplankton in these seas. We deal mainly with the macronutrient elements nitrogen, phosphorus and silicon, and to some extent with iron. The acronym DAIN (Dissolved Available /norganic Mtrogen) is a convenient way to refer to nitrate, nitrite and ammonium, excluding di-nitrogen which is not available to most phytoplankters. 

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