Data from: Fog controls biological cycling of soil phosphorus in the Coastal Cordillera of the Atacama Desert
Data files
Nov 28, 2023 version files 28.37 KB
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README.md
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Total_data.xlsx
Abstract
In this study, we collected topsoil samples (0‒10 cm) from each of 54 subsites, including sites in direct adjacency (< 10 cm) and in 1 m distance to plants, along an aridity gradient across the Coastal Cordillera in the Atacama Desert. The soluble salts anions (NO3‒, Cl‒, and SO42‒) and cations (Ca2+, Na+, Mg2+ and K+) were tested. And we performed soil sequential P fractionation and the oxygen isotope values of HCl-extractable Pi (δ18OHCl-Pi).
README: Fog controls biological cycling of soil phosphorus in the Coastal Cordillera of the Atacama Desert
DOI: 10.5061/dryad.ncjsxkt20
In this study, we collected topsoil samples (0‒10 cm) from each of 54 subsites, including sites in direct adjacency (< 10 cm) and in 1 m distance to plants, along an aridity gradient across the Coastal Cordillera in the Atacama Desert. The soluble salts anions (NO3‒, Cl‒, and SO42‒) and cations (Ca2+, Na+, Mg2+ and K+) were tested. And we performed soil sequential P fractionation and the oxygen isotope values of HCl-extractable Pi (δ18OHCl-Pi).
Description of the data and file structure
All the data have been included in the Excel file. The first column lists 9 sites along the transect, named as “PAP570, PAP950, PAP870, PAP920, PAP1070, PAP1240, PAP1470, PAP1690, PAP2110”. In the second column are the 6 subsites in each sampling site along the transect. Following that, we have listed the values of δ18OHCl-Pi, Resin P, NaHCO3-Pt, NaHCO3-Pi, NaHCO3-Po, NaOH-Pt, NaOH-Pi, NaOH-Po, HCl-Pt, HCl-Pi, HCl-Po, Residual-P, and the concentration of Cl‒, NO3‒, SO42‒, Ca2+, Na+, Mg2+ and K+ in soils.
Sharing/Access information
This is the raw data obtained from the lab work and has no other sources.
Methods
1) Soil salt ions analysis
The soluble salts were extracted by Milli-Q water at a soil/water ratio of 1:10. Then the anions (NO3‒, Cl‒, and SO42‒) concentrations in the extracts were analyzed by ion chromatography (Metrohm IC 850), and those of cations (Ca2+, Na+, Mg2+ and K+) were determined by Inductively Coupled Plasma Optical spectroscopy (ICP-OES, iCAP 6500).
2) Soil sequential P fraction
Sequential P fractionation was performed according to the Hedley sequential fractionation scheme as modified by Tiessen and Moir. In brief, 0.5 g of each air-dried soil sample was sequentially extracted with four reagents including (i) 30 ml deionized water with two anion exchange resin stripes; (ii) 30 mL 0.5 M NaHCO3 solution at pH 8.5; (iii) 30 mL 0.1 M NaOH; and (iv) 25 mL 1 M HCl. Finally, aqua regia was used at 130 0C to extract residual P as chemically most stable P form. After fractionation, the concentration of inorganic P (Pi) in the extracted solutions was measured by the molybdenum blue colorimetric method and measured at 890 nm by the Photometer Analytik Jena SPECORD 205. Total P (Pt) was measured by ICP-OES (iCAP 6500), and the difference between Pt and Pi was used as organic P (Po).
3) Oxygen isotope composition of HCl-extractable Pi
For analysis of the oxygen isotope values of HCl-extractable Pi (δ18OHCl-Pi), we followed the method presented by Tamburini et al. (2010), which produced organic matter-free silver phosphate (Ag3PO4) from acid extracts for oxygen analysis. Twenty g air-dried soils were successively extracted by 0.5 M NaHCO3, 0.1 M NaOH and 1 M HCl at a 1/10 soil/solution ratio (Amelung et al., 2015). We discarded the alkaline extracts to remove most of the organic P compounds and polyphosphates, so that only the 1M HCl extract was used for further purification process. The phosphate was precipitated as ammonium phosphomolybdate and magnesium ammonium phosphate successively. Cation exchange resin (Dowex 50X8, 200‒400 mesh, Sigma-Aldrich, Darmstadt, Germany) was used to extract all cations from the solutions and finally precipitated as silver phosphate (Ag3PO4). The Ag3PO4 crystals were dried in an oven at 50 ℃ for a few days and yellow euhedral Ag3PO4 crystals formed after 1 or 2 days. The δ18O value of Ag3PO4 was measured at the Plant Nutrition group at ETH Zurich. Each sample was analyzed in duplicates (resulting in a total of n=108) using a Vario PYRO Cube (Elemental, Hanau, Germany) with a C-based reactor coupled in continuous flow to an Isoprime 100 isotope ratio mass spectrometer (Isoprime, Manchester, UK). The furnace was kept at 1450 ℃ and the produced reaction gases were concentrated by a purge and trap chromatography system. Calibration was performed against an internal Ag3PO4 standard (δ18O=14.1‰) and two international benzoic acid standards (International Atomic Energy Agency; IAEA 601, δ18O=23.1±0.5‰ and IAEA 602, δ18O=72.2±0.5‰). All values were reported in the conventional delta notation relative to Vienna Standard Mean Oceanic Water (VSMOW) after calibration.