Transformations of Phosphorus

intermediate in sandy loams high in organic C and low in active Fe, and least in acid clays high in active Fe. The increases in soluble P are particularly linked to the transformations of Fe and changes in pH. The main processes are  

Subsequent decreases in solubility may be due to re-sorption or precipitation on clays and oxides as soil conditions continue to change, and decomposition of organic anions chelating P or chelating A1 and Fe with which it would otherwise react. 

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Figure 5. Bio geochemical transformations of phosphorus in forest soils (a) the long-term relative development of different phosphate fractions in soils of the forest ecosystems (b) the relative contents of P fractions in different soil types. Also, the idealized carbon to organic-P rates (C P0) are illustrated (Nihlgard et al., 1994).

The assumption has been repeatedly made, and seems plausible (although it has never been proved in a general form), that at sufficiently high compression any substance will be transformed into a metal. An illustration of this is the transformation of phosphorus into its conducting variant at very high pressure—the Bridgman black phosphorus. 

The thermal film made of long-chain zinc polyphosphates is formed on the surface. When friction increases, the process of transformation of phosphorus compounds into short-chain phosphate glasses is observed and iron sulfide abrasive particles are eliminated by tribochemical acid-base reactions. Under very severe wear conditions (nascent metal surface creation), an iron sulfide is formed, which will be mixed with the phosphate glasses tribofilm. 

Figure 15.10. Simplified scheme of typical transformation of phosphorus in a stratified lake. One milligram of phosphoms introduced into a lake during the stagnation period may lead to the synthesis of 100 mg algae (dry mass), which upon mineralization cause an oxygen consumption in the hypolimnion of 140 mg Oj from the organic P mineralized in the hypolimnion 0.6 mg are assumed to accumulate during the stagnation period, while 0.2 mg are assumed to be adsorbed [e.g., on iron(lll) oxide] and transferred into the sediments another 0,2 mg reaches the surface waters as phosphate by eddy diffusion.

Some studies have also used P NMR to monitor the transformation of phosphorus in laboratory incubations (Table... 

Miltner, A., Haumaier, L. and Zech, W. (1 998)Transformations of phosphorus during incubation of beech leaf litter in the presence of oxides. European Journal of Soil Science 49, 471 -475. 

The major pools and associated transformations of phosphorus in the soil-plant system are presented in Fig. 13.1. These show that the distribution, dynamics and availability of phosphorus in soil are controlled by a combination of biological, chemical and physical processes. Soil solution is the primary source of phosphorus for plants and microorganisms, and most phosphorus is taken up as phosphate (HPO , H2P0 ). The equilibrium concentration of phosphate present in soil solution is very low (<5 fxM) and phosphate removed by plant and microbial uptake must be continually replenished from the inorganic, organic and microbial phosphorus pools. This is especially important in agroecosystems where demand for phosphorus is high and annual off-farm transfer of phosphorus in produce commonly exceeds 20 kg P/ha (Stevenson and Cole, 1999). 

Tate, K.R. (1984) The biological transformation of phosphorus in soil. Plant and Soil 76, 245-256. 

Hupfer, M., Cachter, R. and Ciovanoli, R. (1995) Transformation of phosphorus species in settling seston and during early sediment diagenesis. Aquatic Sciences 75, 305-324. 

Microbial biomass regulates storage and transformation of phosphorus, and flow of phosphorus through the soil microbial pool can be substantial. In phosphorus-limited wetlands containing significant quantities of organic phosphorus, bioavailability of phosphorus may be regulated by... 

Lazarev, A. A. (1945), The accumulation and transformation of phosphorus on miaskites and granite-gneisses in the earliest stages of soil formation. Pochvovedenie 7, 340-347. 

There are only a few examples for the transformations of phosphorus-containing compounds witii baker s yeast [475, 476]. Thus baker s yeast has been used for the synthesis of a-aminophosphonates in a one-pot reaction from aldehyde, diethyl phosphite, and an amine [477]. The reduction of (3-chloro-2-oxo-propyl)-phosphonic acid diethyl ester by baker s yeast gave (2R)-3-chloro-2-hydrox5qjropyl-phosphoric acid diethyl ester, which could be used for the synthesis of (R)-camitine [478-480]. The... 

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