Mineralisation of soil orthophosphate monoesters under pine seedlings and ryegrass

Soil Research ◽  
2004 ◽  
Vol 42 (2) ◽  
pp. 189 ◽  
Author(s):  
C. R. Chen ◽  
L. M. Condron ◽  
B. L. Turner ◽  
N. Mahieu ◽  
M. R. Davis ◽  
...  

The effects of radiata pine (Pinus radiata D. Don) seedlings and ryegrass (Lolium perenne L.) on the mineralisation of orthophosphate monoesters in 7 grassland soils were assessed in a 10-month pot trial using NaOH–EDTA extraction and solution 31P NMR spectroscopy. Extraction with NaOH–EDTA recovered 46–86% of the total soil P, and NaOH–EDTA-extractable organic P determined by molybdate colourimetry ranged between 194 and 715 mg/kg soil, representing 34–85% of the total soil organic P. Orthophosphate monoesters were the predominant species of the extracted organic P in all soils, with much smaller concentrations of orthophosphate diesters, and traces of phosphonates. Concentrations of orthophosphate monoesters were consistently lower in soils under pine (103–480 mg P/kg soil) compared with the initial soils (142–598 mg P/kg soil) and most soils under grass (122–679 mg/kg soil). Mineralisation of myo-inositol hexakisphosphate accounted for 18–100% of the total mineralisation of orthophosphate monoesters in most soils under radiata pine. This suggests that supposedly recalcitrant inositol phosphates are available for uptake by radiata pine, although the extent of this varies among soils.

2019 ◽  
Author(s):  
Jolanda E. Reusser ◽  
René Verel ◽  
Daniel Zindel ◽  
Emmanuel Frossard ◽  
Timothy I. McLaren

Abstract. Inositol phosphates (IP) are a major pool of identifiable organic phosphorus (P) in soil. However, insight on their distribution and cycling in soil remains limited, particularly of lower-order IP (IP5 and IP4). This is because their quantification typically requires a series of chemical extractions, including hypobromite oxidation to isolate IP, followed by chromatographic separation. Here, for the first time, we identify the chemical nature of organic P in four soil extracts following hypobromite oxidation using solution 31P NMR spectroscopy and transverse relaxation (T2) experiments. Soil samples analysed include the A horizon of a Ferralsol from Colombia, of a Cambisol from Switzerland, of a Gleysol from Switzerland and of a Cambisol from Germany. Solution 31P NMR spectra of the phosphomonoester region on soil extracts following hypobromite oxidation revealed an increase in the number of sharp signals (up to 70), and an on average 2-fold decrease in the concentration of the broad signal compared to the untreated soil extracts. We identified the presence of four stereoisomers of IP6, four stereoisomers of IP5, and scyllo-IP4 (using solution 31P NMR spectroscopy). We also identified for the first time two isomers of myo-IP5 in soil extracts: myo-(1,2,4,5,6)-IP5 and myo-(1,3,4,5,6)-IP5. Concentrations of total IP ranged from 1.4 to 159.3 mg P/kgsoil across all soils, of which between 9 % and 50 % were comprised of lower-order IP. Furthermore, we found that the T2 times, which are considered to be inversely related to the tumbling of a molecule in solution and hence its molecular size, were significantly shorter for the underlying broad signal compared to the sharp signals (IP6) in soil extracts following hypobromite oxidation. In summary, we demonstrate the presence of a plethora of organic P compounds in soil extracts, largely attributed to IP of various order, and provide new insight on the chemical stability of complex forms of organic P associated with soil organic matter.


Geoderma ◽  
2015 ◽  
Vol 257-258 ◽  
pp. 48-57 ◽  
Author(s):  
Timothy I. McLaren ◽  
Ronald J. Smernik ◽  
Richard J. Simpson ◽  
Michael J. McLaughlin ◽  
Therese M. McBeath ◽  
...  

2020 ◽  
Vol 22 (4) ◽  
pp. 1084-1094 ◽  
Author(s):  
Jolanda E. Reusser ◽  
René Verel ◽  
Emmanuel Frossard ◽  
Timothy I. McLaren

Inositol phosphates, particularly myo-inositol hexakisphosphate (myo-IP6), are an important pool of soil organic phosphorus (P) in terrestrial ecosystems.


2012 ◽  
Vol 46 (9) ◽  
pp. 4994-5002 ◽  
Author(s):  
Benjamin L. Turner ◽  
Alexander W. Cheesman ◽  
H. Yasmin Godage ◽  
Andrew M. Riley ◽  
Barry V. L. Potter

Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.


2014 ◽  
Vol 11 (6) ◽  
pp. 8569-8605 ◽  
Author(s):  
A. W. Cheesman ◽  
B. L. Turner ◽  
K. R. Reddy

Abstract. Phosphorus (P) cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e. forms derived from biological activity) in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydro-geomorphic and vegetation types. Total P concentrations ranged between 51 and 3516 μg P g


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