Phosphorous fractionation distribution in surface sediments of the Jobokuto Bay

Phosphorus (P) is an essential nutrient that can limit primary productivity in waters. Phosphorus has significant impact on the biogeochemical cycle in marine ecosystems. Surface sediments play an important role in the nutrient dynamics. Riverine input is sources of P to the ocean and sediment plays an important role as a source or sink of P in the coloumn of water. Phosphorous (P) availability is regarded as the most important factor for determining the water quality in coastal waters. However, not all of the P fractions can be released from the sediment. This study was conducted to identify the distribution of phosphorus (P) fractionation in the sediment surface of Jobokuto Bay. Samples were collected from ten locations. Percentage of sedimentary parameters such as sand, silt, clay, and organic carbon were analyzed to find out their relation with various P fractions. The sediment found was mostly sand at the station near to the coast and mud (silt and clay) at offshore stations. The results showed that Ca-P dominant (56.03%) and percentages of Fe-P, OP, and Ads-P were 23.43, 17.41, and 3.2% respectively. Terrestrial inputs and biological deposits cause Ca-P dominant. The bioavailability of P fractions were ranged from 34.45 to 56.1% of the total P (TP) content. The high concentrations of the Ads-P was found in the mud fraction and located at offshore stations. The order of abundance of the major forms of P in the surface sediments of Jobokuto bay is as follows: Ca-P > Fe-P > OP > Ads-P

Comparison of fractionation methods for soil phosphorus with soils subjected to various long-term fertilization regimes on a calcareous soil

Background Diverse phosphorus (P) fractionation procedures presented varying soil P fractions, which directly affected P contents and forms, and their biological availability. Purpose To facilitate the selection of phosphorus (P) fractionation techniques, we compared two procedures based on a long-term experiment on a calcareous soil. Methods The soils containing a gradient P levels were sampled from seven treatments predictor under various long-term fertilizations. The P fractions were then separated independently with both fractionation procedures modified by Tiessen-Moir and Jiang-Gu. Results The results showed that the labile P in Jiang-Gu is significantly lower than that in Tiessen-Moir. The iron and aluminium-bounded P were greater in Jiang-Gu by a maximum of 46 mg kg−1 than Tiessen-Moir. Jiang-Gu fractionation gave similar Ca bounded P to that Tiessen-Moir did at low P level but greater contents at high P level. The two methods extracted much comparable total inorganic P. However, Tiessen-Moir method accounted less total organic P than ignition or Jiang-Gu method (the organic P (Po) estimated by subtract the total inorganic P (Pi) in Jiang-Gu fractionation from the total). P uptake by winter wheat was significantly and positively correlated with all phosphorus fractions in Jiang-Gu; Resin-P, NaHCO3-Pi, D. HCl-P, C. HCl-Pi, NaOH-Po, total-Po in Tiessen-Moir; P fraction categories of Ca-P, Fe & Al-P and total-Pi in both fractionations. Path coefficients indicated that Ca2-P in Jiang-Gu, NaHCO3-Pi and D. HCl-P in Tiessen-Moir had the higher and more significant direct contributions to P uptake among P fractions measured. Conclusions Our results suggested that Jiang-Gu procedure is a better predictor in soil P fractionation in calcareous soils, although it gives no results on organic P fractions.

Internal phoshorus loading potential of a semiarid reservoir: an experimental study

Aim To determine the internal P loading potential of semiarid tropical reservoir sediment while verifying the driving factors that affect P release rates. Methods An experiment was performed with water and sediment from the reservoir Boqueirão de Parelhas in Brazil. The effects of three variables on P release were studied: air temperature (region average of 28 °C and 32 °C, simulating an increase of 4 °C), pH (region average of pH 8, more acidic pH 6 and more alkaline pH 10) and oxygen (presence and absence). In addition, P fractionation analysis was performed on the P forms in the sediment. Results It was found that the minimum P release was in an oxic treatment at pH 6 and temperature 28 °C (0.22 mg m-2 d-1 ± 0.13) and the maximum P release in an anoxic treatment at pH 10 and temperature 32 °C (2.1 mg m-2 d-1 ± 0.15). The total P in the sediment was 597 mg kg-1, and the major P form in the sediment was NaOH-rP, the P bound to aluminum, corresponding to 42% of the total P. Conclusion These results allow us to confirm that the sediment of the Boqueirão reservoir is susceptible to the release of P bound to aluminum due to the prevalence of this form in its sediments concomitant with the high temperatures and alkaline pH of the water. This scenario can be aggravated by climate change.

The exchange of inorganic phosphorus between soil solution and matrix might largely affect the model predictions of terrestrial carbon cycle

<p>Phosphorus (P) availability may influence the response of terrestrial ecosystems to environmental and climate change. Soil biogeochemical (organic) and geophysical (inorganic) P cycling processes are the key players in this regulation. There has been a continuous effort to include P cycling processes into terrestrial biosphere models (TBMs) and many modelling studies agreed on the significance of organic P cycling processes to terrestrial ecosystems. However, the role of inorganic P cycling processes remains unclear. Although the model representations of inorganic P cycling in most TBMs are similar, their parameterisations differ greatly, and none of TBMs have been validated against soil P measurements.</p><p>In this study, we developed a new algorithm based on the two-surface Langmuir isotherm to describe the inorganic P exchange between soil solution and soil matrix in the QUINCY TBM, and tested both the novel and conventional models at five beech forest sites in Germany along a soil P stock gradient, which are the main study sites of the German Research Foundation (DFG) funded priority programme 1685.</p><p>We conducted a literature review on Langmuir P sorption parameters, which indicates that the P sorption capacity (S<sub>max</sub>) is strongly correlated with soil texture and the Langmuir coefficient (k<sub>m</sub>) is strongly correlated with soil pH and organic matter (OM) content. We divided soil P sorption sites into the OM-rich clay and silty sites and OM-poor sandy sites and extracted empirical equations to calculate their S<sub>max</sub> and k<sub>m</sub>.</p><p>The two-surface Langmuir isotherm approach was implemented to QUINCY, and both the novel and conventional (one-surface Langmuir isotherm) models were applied to the study sites. The models were evaluated with observed soil inorganic P fractionations, foliar N and P contents, and normalized vegetation carbon (C) without calibration. The novel model significantly improved the goodness of model fit to P fractionation measurements at all sites. Both models were able to adequately capture the observed foliar N and P contents, but only the novel one reproduced the observed pattern of vegetation C along the soil P gradient.</p><p>We further tested the effect of both models on the responses to CO<sub>2</sub> addition, P addition and C&P addition at all study sites. The conventional model showed stronger ecosystem responses to P and C&P additions than the two-surface Langmuir one, especially at P-poor sites. It is probably due to that plants store more added P in the conventional model than the novel one. We also tested the sensitivity of both models to the P cycling parameterisation at one low-P site. Despite better model fit to the observed soil P fractionation, the novel model also produced higher and more robust gross primary production, foliar P content and vegetation C than the conventional one.</p><p>In summary, we showed that the two-surface Langmuir isotherm approach adequately reproduced the observed soil P fractionations and the pattern of vegetation C along a soil P gradient, owing to its better representation of inorganic P cycling and thus C-P interactions, particularly at low-P ecosystems.</p>

Fractionation of industrial lignins: opportunities and challenges

Fractionation represents a valid option for the valorisation of technical lignin, a readily available yet heavily underutilised resource. The developed fractionation strategies and the applications of lignin fractions are here critically reviewed.

A Look into the Past: Tracing Ancient Sustainable Manuring Practices by Thorough P Speciation of Northern European

Regionally restricted, hums-rich topsoils in Southwest Norway and the Baltic Sea region of Germany and Denmark were formed by inputs of various amendments (combustion residues and marine biomass) and, therefore, were classified as Anthrosols. For a deeper insight into the ancient management practices, we investigated the elemental and P-composition in the upper and underlying horizons from 12 soil profiles in the Jæren region, at the islands of Karmøy and Feøy (Norway), at the island of Fehmarn and the peninsula of Wagrien (Germany), and at the islands of Poel (Germany) and Sjaelland (Denmark). We used aqua regia digestion and the complementary methods of sequential P fractionation, phosphorus K-edge X-ray absorption near edge structure (P-XANES) spectroscopy, and 31P nuclear magnetic resonance (31P-NMR) spectroscopy. Results were compared with the composition of differently amended and/or un-amended soils from other studies. In addition, archaeological literature was used to confirm possible inputs of specific P-containing amendments in ancient agriculture. The P composition from SF of the Anthrosols in Norway (44% NaOH-Pi >1 8% NaOH-Po > 14% NaHCO3-Pi, 12% H2SO4-P > 7% NaHCO3-Po > 3% residual-P = 3% resin-P) and complementary archaeological literature provided strong indication for the use of peat, sheep manure, compost, and human excreta. The Anthrosols in the Jæren region have been formed from peat, which had been used as alternative bedding material and had been mixed with sheep and/or cattle manure. The P-composition in the Anthrosols at the island of Fehmarn and at the peninsula of Wagrien (42% H2SO4-P > 25% residual-P > 10% NaOH-Po, 8% NaOH-Pi: > 6% NaHCO3-Pi and NaHCO3-Po, 4% resin-P) resulted from the application of domestic cattle manure. This was strongly supported by archaeological findings of cattle bones in this region, as well as high proportions of Ca-P, as confirmed by P-XANES. The predominance of Po in the Anthrosols at the island of Poel and Sjaelland (31% NaOH-Po > 23% NaHCO3-Po, 21% H2SO4-P > 11% NaOH-Pi > 8% NaHCO3-Pi > 4% residual-P, 3% resin-P, in agreement with results from 31P-NMR) indicated low ancient inputs of various excrement or manure. This was supported by low livestock history at the island of Poel. In conclusion, these agricultural techniques can be considered as sustainable P recycling and soil amendment since they improved soil fertility for many generations.

Methods for Sample Collection, Storage, and Analysis of Freshwater Phosphorus

Although phosphorus (P) is an essential nutrient for biological productivity, it can cause freshwater degradation when present at fairly low concentrations. Monitoring studies using continuous sampling is crucial for documenting P dynamics in freshwater ecosystems and to reduce the risk of eutrophication. Despite literature updates of developments of the analytical methods for measurement of P species in natural waters, there has been no comprehensive review addressing freshwater sample collection, sample preparation, and sample treatment to fractionate and characterize different forms of P. Therefore, this paper aims to elaborate the different techniques for freshwater sampling and to introduce alternative laboratory methods for sample preservation and P fractionation. The advantages and disadvantages of various sampling techniques, including the traditional manual and the recently developed automatic and passive methods, are presented to highlight the importance of collecting representative freshwater samples. Furthermore, we provide suggestions for sample pretreatment, including filtration, transportation, and storage steps to minimize microbial activity and to maximize the accuracy of measurement of various P fractions. Finally, the most common laboratory methods to measure dissolved and particulate as well as the organic and inorganic freshwater P fractions are efficiently provided. Using this guide, a comprehensive monitoring program of P dynamics in freshwater ecosystems can be developed and applied to improve water quality, particularly of P-rich freshwaters.

Soil phosphorus bioavailability as influenced by long-term management and applied phosphorus source

Soil phosphorus (P) availability may be impacted by management practices, thereby affecting plant P uptake and plant response to P amendments. The aim of this study was to determine the effects of long-term management on soil P pools and to assess the response of P bioavailability, plant growth, and P uptake to mineral versus manure P treatments. Soils were collected from plots under organic (ORG), organic with composted manure (ORG + M), conventional (CONV), and restored prairie (PRA) management. Italian ryegrass (Lolium multiflorum L.) seedlings were grown in the greenhouse for 106 d in soils amended with various rates of manure or mineral P. The ORG soil had lower concentrations of labile P (resin-P and NaHCO3-P) compared with the CONV and PRA soils, as determined by sequential P fractionation prior to planting. Ryegrass biomass (root + shoot) and shoot P uptake from soils receiving no P were significantly lower for the ORG than all other management systems. Although apparent P use efficiency of the whole plant was increased by low P rate in the ORG management system, the source of applied P, manure > mineral, only influenced Olsen test P.

Developed and Evaluation of Slow Release Phosphorus Fertilizer Using Mono-ammonium Phosphate and Di-ammonium Phosphate

Phosphorus (P) availability is generally low in Calcareous soils due to its association with soil constituents forming other P compounds that are of low solubility and availability for plant uptake. In particular, phosphorus use efficiency (PUE) in Saudi Arabia agricultural soils is very low. Therefore, there is a growing interest in finding an effective approach to improve PUE. Fertilizer coating with polymers has become a recognized strategy for controlling the release of nutrients and regulating their availability in the soil. In this study, two fertilizers types of phosphate-bound alginate-graft polyacrylamide (P-Alg-g-PAM) were prepared using mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP). A matrix of sodium alginate (Alg) and poly (vinyl alcohol) (PVA) was phosphorylated using either MAP or DAP, followed by grafting with acrylamide. An incubation study was conducted by using three soils with different CaCO3 content to evaluated the performance of developed fertilizer (slow-release MAP and slow-release DAP) compared with the commercial MAP and DAP fertilizer. The developed fertilizer exhibited P release of 77% for the slow release MAP and 57% for the slow release DAP until the 45 days of the application at pH 7 and 25°C. The results of incubation study, indicated that the available soil-P significantly (P<0.05) varied between the different P fertilizers. In the beginning of the incubation period, the available soil- P into different soil from slow-release MAP and DAP was slightly lower than the commercial MAP and DAP, but with the time proceed, the slow-release MAP and slow-release DAP resultant in more available soil- P than the uncoated MAP and uncoated DAP. The results indicated that, the fertilizers could be classified into two groups: the first “fast release” group showed total P release in the 10 days after incorporation of uncoated MAP and uncoated DAP fertilizers into soil. The second “slow release” group included coated slow- release MAP and coated slow- release DAP fertilizer, released of about 70% during the period of 10-30 days after incubation. The results of P fractionation chemical analysis indicated that, the soluble, exchangeable-P, Ca-occluded-P fraction, was the most dominated P forms distributed among the soils.