Amounts Of Organic Phosphorus Research Articles

Processes and their explanatory factors governing distribution of organic phosphorous pools in lake sediments.

The amount of organic phosphorus (OP) and its distribution among different pools in lake sediments depends on biotic and abiotic processes driving the OP fractionation. Key environmental factors governing these transformations processes between OP fractionations in sediments were studied on the basis of geochemical characteristics of OP pools in relation to environmental factors in the sediments. The results illustrate that the factors influencing the accumulation or depletion of different OP pools were intrinsically dependent on the composition of the deposited organic matter (OM). During the mineralization of the OM the microorganisms excrete the enzyme alkaline phosphatase, accelerating the OP hydrolysis, and thereby setting the grounds for the bacterially-mediated oxidation of OM. There are two main degradation products of the labile OP pool (LOP) and the moderately labile OP pool (MLOP): Either the OP is transformed to a dissolved organic or inorganic P form, and thereby released to water column, or OP is transformed to a non-labile OP pool and stored in the sediments. A comparative study showed that oxy-hydroxides of iron (Fe) and aluminum (Al) only played an important role in influencing OP fractionation in Lake Wuliangsuhai, while the complexation reactions of OP with calcium ions and sorption to its minerals are key factors governing the OP fractionation in the two alkaline lakes. It is worth noting that a significant correlation between the Fe-P pool and the pools of LOP and MLOP indicates that the degradation of the rather labile OP pools are highly dependent on the iron redox reaction.

Role of hydrological conditions on organic phosphorus forms and their availability in sediments from Poyang Lake, China.

Biogeochemical cycling of internal bioavailable organic phosphorus (OP) is an important source for algal bloom after exogenous P inputs are controlled. Biogeochemical cycling may be affected by hydrological processes and the water cycle and eventually result in water quality deterioration and accelerated lake eutrophication. Poyang Lake is the largest freshwater lake in China. The hydrological condition of the lake has significantly changed since 2003, thereby causing a continuous decline in water level. In this study, sediments were obtained from different elevations and different hydrological conditions in Poyang Lake. The sediments were subjected to sequential extraction and enzymatic hydrolysis to determine the transformation of OP into various chemical forms, their bioavailability, and the exchange between the sediments and overlying water. Results suggested that the descending water level caused by the changes in hydrological conditions was one of the major factors affecting OP dynamics. Long exposure of sediments resulted in high OP content and increased availability. The increased OP content in exposed sediments was primarily derived from H2O-Po and NaOH-EDTA-Po. Moreover, the increased OP availability in exposed sediments was mainly attributed to the increasing amount of orthophosphate caused by processes governing sediment exposure, promotion of OP release, and transformation of chemical forms from nonlabile to labile. Sediment exposure time and area have considerably expanded since 2003; hence, the amounts of OP and orthophosphate in the sediments have increased by as much as 600 and 120 tons in the lake every year, respectively. Although the increase in orthophosphate only accounted for 6% of the external total phosphorus, the local region may exhibit higher risk for OP release from the sediments, thereby accelerating quality deterioration. Therefore, maintaining reasonable hydrological conditions is important to protect Poyang Lake water.

Distribution characteristics of organic phosphorus in sediments from Lake Hulun, China.

The amount of organic phosphorus (OP) and its distribution among different pools in lake sediments depend on biotic and abiotic processes driving OP fractionation. The key abiotic factors governing these transformation processes between different OP fractions in sediments were studied on the basis of distribution characteristics of OP pools in sediments from Lake Hulun (HLH). The results showed the order of the size of OP pools in the surface sediments from Lake Hulun to be: Re-OP (residual OP) ≫ FAOP (fulvic acid fraction) ≥ HCl-OP (OP extracted by HCl) > HAOP (humic acid fraction) ≫ LOP (labile OP); lower concentrations of LOP were found in lake surface sediments with high pH (pH > 9) of lake overlying water indicating a governing role of pH in LOP degradation in an aquatic environment. The pattern of total OP (TOP) spatial distribution showed an obvious decreasing trend from the west to the east lake districts in surface sediments from HLH, which was attributed to the inputs of dust and dry grass driven by the prevailing wind and the finer grain size in the west lake districts. However, the spatial distribution pattern of dissolved OP (DOP) in overlying water, which presented different trends with TOP and total organic carbon (TOC) in surface sediments, indicated that the biological factors and terrestrial inputs showed a joint influence on DOP distribution in HLH. The higher levels of Re-OP and lower levels of HCl-OP observed in HLH may reveal that calcium ions and their minerals were the key governing factors of OP fractionation in sediments from HLH. This work revealed the main abiotic process or mechanism driving OP fractionation in the aquatic environment helping to understand the geochemical information archived in OP pools in lake sediments.

Isolating the influence of pH on the amounts and forms of soil organic phosphorus

SummarySoil pH influences the chemistry, dynamics and biological availability of phosphorus (P), but few studies have isolated the effect of pH from other soil properties. We studied phosphorus chemistry in soils along the Hoosfield acid strip (Rothamsted, UK), where a pH gradient from 3.7 to 7.8 occurs in a single soil with little variation in total phosphorus (mean ± standard deviation 399 ± 27 mg P kg−1). Soil organic phosphorus represented a consistent proportion of the total soil phosphorus (36 ± 2%) irrespective of soil pH. However, organic phosphorus concentrations increased by about 20% in the most acidic soils (pH < 4.0), through an accumulation of inositol hexakisphosphate, DNA and phosphonates. The increase in organic phosphorus in the most acidic soils was not related to organic carbon, because organic carbon concentrations declined at pH < 4.0. Thus, the organic carbon to organic phosphorus ratio declined from about 70 in neutral soils to about 50 in strongly acidic soils. In contrast to organic phosphorus, inorganic phosphorus was affected strongly by soil pH, because readily‐exchangeable phosphate extracted with anion‐exchange membranes and a more stable inorganic phosphorus pool extracted in NaOH–EDTA both increased markedly as soil pH declined. Inorganic orthophosphate concentrations were correlated negatively with amorphous manganese and positively with amorphous aluminium oxides, suggesting that soil pH influences orthophosphate stabilization via metal oxides. We conclude that pH has a relatively minor influence on the amount of organic phosphorus in soil, although some forms of organic phosphorus accumulate preferentially under strongly acidic conditions.

Dynamics of phosphorus forms in the bottom sediments and their interstitial water for the Prut River (Moldova)

Phosphorus concentration in rivers results from both external inputs and internal loading from the bottom sediments. Seasonal, spatial, and multi-annual dynamics of phosphorus forms in bottom sediments and their interstitial water for the river Prut (Moldova) were evaluated. In order to determine content of total phosphorus in the bottom sediments, fresh (wet) samples were subjected to persulfate oxidation. The content of inorganic phosphorus was determined after acidic oxidation of samples. The amount of organic phosphorus was obtained by subtracting inorganic phosphorus from the amount of total phosphorus. Content of phosphorus forms in interstitial water was determined after centrifugation of fresh (wet) sediments. In general, the shape of dynamics of the amounts of inorganic phosphorus in sediments was close during years 2009, 2010, and 2011, with registered higher contents of this form on the middle course of the river. The spatial dynamics of organic phosphorus is less homogeneous along the Prut River. During 2009, higher amounts of organic phosphorus were recorded on the middle sector. During the spring of year 2010, the content of organic phosphorus in sediments was practically not changed along the river. The ratio of inorganic/organic phosphorus in bottom sediments was similar during the researched years, with the predominance of the inorganic phosphorus being recorded. Also, the increasing tendency of the percentage of organic phosphorus from spring to summer was identified. Generally, appropriate spatial and seasonal dynamics of phosphorus forms in bottom sediments and their interstitial water were recorded, although sometimes with some differences.

Proposal for a more suitable method to extract soil organic phosphorus

Abstract An attempt was made to establish a suitable method for extracting the maximum amount of organic phosphorus (org-P). The resin-acetyl acetone extraction method (R-AA method) is suggested to represent a more suitable method than those published previously by various researchers. The R-AA method is mild but can extract a large amount of organic matter, especially org-P, with the least extent of hydrolysis of the org-P.

Influence of Natural Drainage on the Distribution and Forms of Phosphorus in Some Iowa Prairie Soils

AbstractTotal, inorganic, organic, and available P were determined for 12 loess‐derived prairie soil profiles. The amount of total phosphorus (TP) is high near the surface, has minimum values from 1 to 3 ft, has maximum values from 3 to 6 ft, and has nearly uniform values below 6 to 7 ft. The higher amounts near the surface are due to organic phosphorus (OP). The amount of OP in the poorly drained soils is about one‐half that in the better drained members of the topo‐sequence.Differences in organic carbon (OC)/OP ratios between the poorly and better drained soils are appreciable, with the poorly drained soils having the higher ratios.Difference in extractable or available phosphorus (AP) within and between profiles may be interpreted when pH, extractable Fe and Al, rooting depth of plants, TP and OC/OP ratios are considered. Phosphorus differences between soils of southeast and southwest Iowa are appreciable. The role of P in soil genesis studies is discussed.

Soil organic phosphorus

Abstract The extraction and resin fractionation procedures for determination of amounts and kinds of soil organic phosphorus (Pt IV of this series) were applied to a sequence of four soils having common parent material and vegetation but varying in altitude, rainfall, and temperature. Three different zonal soil groups were represented in the sequence: the brown-grey earths, yellow-grey earths, and high country yellow-brown earths. For each soil type, samples of the topsoil and of three individual horizons (A, AB, and B) were examined. The amount of organic phosphorus extracted and its occurrence in different fractions were similar for comparable samples from each soil type, suggesting that the amount and nature of soil organic phosphorus are determined primarily by parent material and biological factors. The kinds of organic phosphorus compound present in different horizons of each soil were clearly differentiated. Humic acid-associated organic phosphorus and inositol phosphates were present in comparable...

Soil organic phosphorus

Abstract The extraction and resin fractionation procedures for soil organic phosphorus developed in Part I were applied to a representative group of New Zealand soil types (18 soils). The amount of organic phosphorus extracted varied (59–87 per cent of total organic P, mean 75 per cent), but no clear pattern was evident. The binding of inorganic and organic phosphorus in the soil were evidently distinct processes, the organic phosphorus being more readily extractable by dilute KOH. Essentially the same pattern was found for all soils for the resin fractionation of the 0.3M KOH extracts. The organic phosphorus was split into humic-associated organic phosphorus and acid-soluble organic phosphorus, both fractions being separated from inorganic phosphorus. The much higher retention of organic phosphorus on resin with 3 per cent cross-linking compared with 8 per cent cross-linking was also found for all soils. Analysis of soils from no P and high P plots from a phosphate fertiliser field trial indicated that the extraction and fractionation procedures would be valuable for following the transformation of fertiliser phosphorus into soil organic phosphorus in long-term trials but would not be suitable for following short-term trends. Lines of investigation developing from the present work are discussed.

Effect of incubation and liming on the phosphorus fractions in soil

Samples from two field trials were incubated at 20°C for seven months with or without an addition of 1 per cent CaCO3. Both the samples of loam soil and silt soil originated from the surface inch of plots treated with no phosphate, superphosphate or hyperphosphate, resp. It was found that liming did not in any case increase the amount of organic phosphorus mineralized during the incubation. Its effect was observed in the distribution of this phosphorus in the various fractions of inorganic phosphorus. In the distinctly acid samples which were incubated without lime the mineralized phosphorus seemed to accumulate as the ammonium fluoride-soluble and alkali-soluble forms, while in the neutral samples incubated with lime an increase only in the former fraction was detected. When the samples from the hyperphosphate plots were incubated without lime, apparently some apatite of the fertilizer was dissolved and sorbed as the ammonium fluoride soluble or alkali-soluble forms. No decrease in the acid-soluble fraction of these samples incubated with lime did occur.

QUANTITATIVE FRACTIONATION OF ORGANIC PHOSPHORUS COMPOUNDS IN SOME ALBERTA SOILS

Soil samples from the A and B horizons of nine virgin profiles and from the A2 horizons of two of the profiles were analysed for organic phosphorus content. The nine profiles represented five of the major soil zones of Alberta. Organic phosphorus extracted with HCl and NaOH treatments was separated into three fractions using an anion exchange column. The three fractions contained unidentified phosphorus compounds, meso-inositol hexaphosphate and a supposed isomer of meso-inositol hexaphosphate respectively.The unidentified compounds in the A horizons contained the major proportion of the organic phosphorus. Of the two inositol hexaphosphate compounds measured, the supposed isomer was present in larger quantities than the meso form with the exception of the Hemaruka soil in which the meso form was slightly higher. The three fractions together accounted for only 54.0 per cent of the total organic phosphorus.The largest amounts of organic phosphorus in the B horizons also occurred in Fraction 1. However, in the B horizons this fraction accounted for 63.4 per cent of the total organic phosphorus in comparison to the 42.2 per cent in the first fraction of the A horizons. The total of the two inositol hexaphosphate compounds in the B horizons accounted for only 2.8 per cent of the total organic phosphorus while in the A horizons the same compounds accounted for 11.8 per cent of the total organic phosphorus. Of the 2.8 per cent organic phosphorus that was present as inositol hexaphosphate in the B horizons, the greatest proportion was in the meso form, while the reverse was true of the A horizons.The A3 horizons contained 6.9 per cent of the total organic phosphorus in the inositol hexaphosphate form, with the larger amount in the meso form.

Phosphate responses in relation to soil tests and organic phosphorus

Phosphate responses of wheat in a number of soil types have been correlated with the amounts of phosphate extracted by ten different methods. Of these only total organic phosphorus, and inorganic phosphorus extracted with hot 0·1N caustic soda, were significantly related to phosphate response, the former at the 1% level and the latter at the 5% level. The amount of organic phosphorus in the soil was also found to be significantly related, in each instance at the 5% level, to phosphate responses of grass and the percentage phosphate in the grass. When the amount of organic phosphorus was considered together with the phosphate retention capacity of the soil, to give a measure of available mineralized phosphate, the relationships to response (and uptake of phosphorus by grasses) was more significant than with organic phosphorus alone.The organic phosphorus fraction accounted for about 86% of the total soil phosphorus. Measurable amounts of water-soluble organic phosphorus were found with all the soils. The amounts were, however, not significantly related to phosphate response. Moreover, it was found that while the soil extract containing organic phosphorus decomposed, it did so without the production of mineral phosphate. From this, and further evidence in the literature, it is considered that the organic complex in the soil, rather than the water soluble phosphorus, is the main source for the plant.

Availability for plants of phosphorus in some virgin peat samples

The availability to plants of native peat phosphorus was studied by chemical methods and by a pot experiment in which three successive oat crops were grown with peat as the only source of phosphorus. The eight samples were collected from virgin peat lands. They were air-dried and ground. The samples were found to represent three different types of phosphorus condition: the first group contained relatively high amounts of inorganic phosphorus which was fairly easily available; the second group had a very high capacity to fix phosphorus which made its high quantity of inorganic phosphorus difficultly available; the third group was very poor in total and inorganic phosphorus but the latter was easily soluble and available to plants. On the basis of the capacity and intensity factors determined according to the method by Teräsvuori and also on the basis of inorganic phosphorus extractable by water fairly reliable predictions could be made of the mutual order of the samples as phosphorus supplyer to the plants in the pot experiment. In an incubation experiment at 27°C the amounts of organic phosphorus mineralized during the period of four months were in some of the samples quite marked, even 40 mg/l, and in most of the samples they corresponded to 5 to 15 per cent of the organic phosphorus. The amounts of phosphorus taken up by the oat crops under the favourable conditions of the pot experiment varied from 11 to 60 mg/l or from 20 to 120 kg/ha.

Phosphorus in various depths of some virgin peat lands

In the present paper results are reported concerning the total content as well as solubility of organic and inorganic phosphorus in 122 peat samples which were collected from various depths of 30 peat lands. The total phosphorus content of all the samples was rather low and no regularity in the influence of the depth upon this quantity could be demonstrated. There seemed to be some tendency to an increase in the P-content with increasing depth in the peat lands of lower quality. In peat lands of higher quality the opposite often held true. A large part of the phosphorus occurred in organic form, and, almost without exception, this percentage of total phosphorus increased with the depth: in undecomposed plant material this proportion was about 50—60 per cent, in the surface layers 70 per cent, on the average, in deposits deeper than 50 cm seldom less than 80 per cent and it could even reach 95 per cent. 1he amount of organic phosphorus expressed as a percentage of organic dry matter was low in most of the samples and although it tended to increase with the depth only in 11 of all the 122 samples values higher than 0.1 per cent were obtained. Even if an allowance is made for the conditions prevailing in peat lands these low percentages of organic phosphorus indicate that, from the microbiological point of view, no rapid mineralization of the organic phosphorus compounds is probable. The inorganic phosphorus content was low and tended to decrease from the surface to deeper layers. The solubility of inorganic phosphorus, however, dropped much more drastically. Thus in the deeper layers the amount of easily extractable inorganic phosphorus could be negligible. The solubility of organic phosphorus also impaired with the depth. The phosphorus economy of peat lands was discussed on the basis of the results obtained.