Pyrophosphate and orthophosphate addition to soils: sorption, cation concentrations, and dissolved organic carbon

Soil Research ◽  
2007 ◽  
Vol 45 (4) ◽  
pp. 237 ◽  
Author(s):  
T. M. McBeath ◽  
E. Lombi ◽  
M. J. McLaughlin ◽  
E. K. Bünemann
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Calcium Concentration ◽  
Solid Phase ◽  
Iron Concentration ◽  
Solution Chemistry ◽  
Soil Types ◽  
Significant Yield ◽  
Complexation Reactions ◽  
Soil Solid Phase

Liquid polyphosphate fertilisers contain both orthophosphate and pyrophosphate, and have shown significant yield increases compared to granular orthophosphate fertiliser on highly phosphorus (P) fixing soils. The P sorption chemistry of the dominant P species in a polyphosphate fertiliser (pyrophosphate and orthophosphate) was compared on a range of Australian soils, and the effect of these P species on equilibrium solution chemistry was also examined. Phosphorus supplied as pyrophosphate had a stronger sorption affinity than orthophosphate in all soils. The greater efficiency of pyrophosphate-based fertiliser on some soil types is therefore not due to reduced sorption of this P supplied as pyrophosphate compared to P supplied as orthophosphate fertiliser. In general, the addition of pyrophosphate to soil resulted in a larger decrease in calcium concentration in solution compared to orthophosphate. In contrast, there was an increase in iron concentration in solution with pyrophosphate addition, indicating sequestration reactions associated with the dissolution of dissolved organic carbon into soil solution. The pyrophosphate ion generally mobilised more Fe into solution than orthophosphate in several soils, likely through complexation reactions leading to Fe desorption/dissolution from the soil solid phase. These findings highlight the differences in soil chemical reactions that occur with the addition of polyphosphate fertilisers, which may contribute to their yield advantage in some soil types.

scholarly journals The effect of dissolved organic carbon on pelagial and near-sediment water traits in lakes

2011 ◽  
Vol 74 (2) ◽  
pp. 133-139 ◽  
Author(s):  
Krzysztof Banaś
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Redox Potential ◽  
Environmental Conditions ◽  
Calcium Concentration ◽  
Total Hardness ◽  
Sediment Layer ◽  
Ph Values ◽  
Doc Concentration ◽  
Good Transparency

The effect of dissolved organic carbon (DOC) on the environmental conditions of macrophytes has been studied in 35 lakes divided into soft- and hardwater: oligohumic (&lt;4.0 mg C dm<sup>-3</sup>), α-mesohumic (4.0-8.0 mg C dm<sup>-3</sup>), β-mesohumic (8.1-16.0 mg C dm<sup>-3</sup>) and polihumic (&gt;16.0 mg C dm<sup>-3</sup>). The optimum environmental conditions for macrophytes have been found in oligohumic lakes, characterised by low water colour and its good transparency. In soft- and hardwater lakes increasing concentration of DOC is accompanied with an increase in the colour (r=0.95), while the visibility decreases. With increasing DOC in the near-sediment layer the pH values decrease while the concentration of nitrogen increases and the concentration of phosphorus slightly increases. In hardwater lakes with increasing DOC concentration, the redox potential, conductivity, total hardness and calcium concentration in the near-sediment water decrease, whereas the content of CO<sup>2</sup> remains at a very low level.

scholarly journals The importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated landscape

2012 ◽  
Vol 9 (6) ◽  
pp. 7465-7497 ◽  
Author(s):  
T. Wohlfart ◽  
J.-F. Exbrayat ◽  
K. Schelde ◽  
B. Christen ◽  
T. Dalgaard ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Agricultural Land ◽  
Stream Water ◽  
Soil Types ◽  
Organic Soils ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen

Abstract. The surrounding landscape of a stream has crucial impacts on the aquatic environment. This study pictures the hydro-biogeochemical situation of the Tyrebaekken creek catchment in central Jutland, Denmark. The intensively managed agricultural landscape is dominated by rotational croplands. One northern and one southern stream run through the catchment before converging to form a second order brook. The small catchments mainly consist of sandy soil types besides organic soils along the riparian zone of the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. On each sampling day, 20 points along the stream were sampled as well as eight drain outlets and two groundwater wells. Total dissolved nitrogen, nitrate, ammonium nitrogen and dissolved organic carbon (DOC) concentrations were measured and dissolved organic nitrogen (DON) was calculated for each grabbed sample. Electro-conductivity, pH and flow velocity were measured during sampling. Statistical analyses showed significant differences between the northern, southern and converged stream parts, especially for nitrate concentrations with average values of 9.6 mg N l−1, 1.4 mg N l−1 and 3.0 mg N l−1, respectively. Furthermore, throughout the sampling period DON concentrations increased from 0.1 mg N l−1 to 2.8 mg N l−1 and from 0.1 mg N l−1 to 0.8 mg N l−1in the northern and southern streams, respectively. This corresponded to a contribution of up to 81% to total dissolved nitrogen. Multiple-linear regression analyses performed between chemical data and landscape charateristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%). On the other hand, organic soil frequency was positively correlated to the corresponding dissolved organic carbon concentrations. Croplands also had a significant influence but with weaker correlations. For our case study we conclude that soil types and corresponding biogeochemical properties have a major influence on stream water chemistry. Meanwhile, the contribution of dissolved organic nitrogen to the total nitrogen budget was substantial in this agricultural dominated landscape.

scholarly journals Determination of dissolved organic carbon in soils with UV spectroscopy, ultrasonic dispersion pre-treatment and separation with size exclusion chromatography .

2014 ◽  
Vol 4 ◽  
Author(s):  
Schomakers Jasmin ◽  
Mentler Axel ◽  
Herwig Mayer
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Size Exclusion Chromatography ◽  
Uv Spectroscopy ◽  
Energy Levels ◽  
Carbon Pool ◽  
Size Exclusion ◽  
Soil Types ◽  
Exclusion Chromatography ◽  
Pre Treatment

This study aimed to reveal differences in UV (ultraviolet) -absorbing dissolved organic carbon (DOC) between three prominent Austrian soil types: a Cambisol and a Chernozem developed from Tertiary marl, both under agricultural management, and a Podzol from a mixed coniferous beech forest stand. Topsoil samples (0–300 mm) were pre-treated, air-dried, sieved and four grams of each probe was added to 80 cm<sup>3</sup> of de-ionized water and subjected to ultrasonic treatment with specific energies of 6.7 J cm<sup>-3 </sup>and 161 J cm<sup>-3</sup>, respectively, which dispersed the macroaggregates and released formerly occluded soluble carbon. The soils were investigated for morphological differences with a scanning electron microscope after sonication. The suspensions were filtered &lt; 0.45 µm and UV-spectroscopy at 254 nm was performed after the dispersion pre-treatment. In addition the suspension was separated by high performance size exclusion chromatography linked to an UV-vis detector measuring at 254 nm and 210 nm and dissolved organic carbon (DOC) was determined. More DOC was released with higher specific energies for all soil types in the sequence Podzol &gt; Cambisol &gt; Chernozem but the differences in SOM/DOC ratio became less significant with increasing ultrasonic energy. The detected molecules were in the range of 1300-1600 Da for Cambisol, 1500-5400 Da for Chernozem and 1700-10400 Da for Podzol. The different energy levels reached different carbon pools. Based on a model according to von Lützow et al. (2008), the applied energy levels of 6.7 J cm<sup>-3</sup> reached the active carbon pool consisting of plant residues and exudates, and microbial/faunal biomass and residues. Sonication with 161 J cm<sup>-3</sup> dispersed more aggregate fractions and released carbon from the intermediate carbon pool where biogenic aggregation preserves the organic matter pool.

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