Main Experiment: Phosphorus fractions of soils (Site A)

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Dataset Abstract

Soil chemical laboratory analyses of 30 plots of site A of experimental study plots at Xingangshan. Samples were taken and provided from Thomas Scholten and Peter Kühn (Tübingen University). Analysis was done at Freiburg University with the Hedley fractionation method (Modification by Tiessen & Moir, 1993) for the top three (0-5, 5-10, 10-20cm) depth increments.

Dataset Design

Samples were provided from Thomas Scholten and Peter Kühn from Tübingen University Department Soil science and Geomorphology. 3 depths (0-5, 5-10, 10-20 cm) were used airdried and sieved < 2 mm.

Spatial Extent

Experimental Site A
29°08'-29°11'N
117°90'-117°93'E

Published

Master Thesis Peters F. (2015): Can diversity overcome nutirent limitation in a young afforested stand in sub-tropical China; Chair of Silviculture; Faculty of Environment and Natural Resources, Albert-Ludwigs Universität Freiburg im Breisgau, Germany.

Temporal Extent

Samples were collected from 2010 to 2011.

Data Analysis

Phosphorus fractions in soils were analyzed by the sequential extraction method according to Hedley (Hedley et al. 1982a). The whole fractionation process used for this data is described in detail by Tiessen and Moir (2008). The organic fractions were calculated while substracting the measured inorganic fraction from the measured total P of the same extract. The general usefulness of this method to determine P in fractions of distinctly different solubility is widely discussed (Condron and Newman 2011, Cross and Schlesinger 1995, Yang and Post 2011). The individual fractions can be described as readily soluble and exchangeable Pi (Pi Resin), desorbable Pi (pi_nahco3) and readily mineralizable Po (po_nahco3), Fe/Al associated Pi (pi_naoh, pi_naoh_s) and Fe/Al associated Po (po_naoh, po_naoh_s), Ca associated Pi (pi_1mhcl, pi_hcl_conc), Ca associated Po (po_hcl_conc), and residual P (tp_residual). For the purpose of subsequent statistical analyses, the Hedley fractions can be grouped by their solubility in labile (pi_resin, pi_nahco3 and po_nahco3), moderate labile (pi_naoh, pi_naoh_s, po_naoh, po_naoh_s, pi_1mhcl) and stable P pools (pi_hcl_conc, po_hcl_conc, tp_residual) as commonly found in literature. (Cross and Schlesinger 1994, de Schrijver et al. 2011, Stevenson and Cole 1999, Yang and Post 2011).

Data columns available in the raw data part of this dataset

lab_num
laboratory number of laboratory of soil science and geomorphology in Tübingen;
Data group: Laboratory number of Laboratory of Soil Science and Geomorphogy in Tübingen
Values
5239
4890
4889
5238
4888
Site
Experimental Site of the BEF-China Experiment
Data group: Experimental Site
Values
A
Plot
Plot within the experimental site
Data group: BEF research plot name
Values
C32
F21
E34
F22
E24
Increment
Depth increment of the soil core (cm range)
Data group: Soil depth
Values
10-20
0-5
5-10
pi_resin
Inorganic P extracted with Resin bags in 20ml H20 for 16hrs, measured in 0.5M HCL
Unit: µg/g
Data group: Phosphorus
Values
0.21114
10.26897
10.15291
10.184384999999999
10.134419999999999
* Nitschke, R. also contributed to this column.
pi_nahco3
Inorganic P measured in Extract which was shaken in 25ml NaHCO3 for 16hrs
Unit: µg/g
Data group: Phosphorus
Values
1.384695
1.3258649999999998
0.98692
1.24338
1.36998
* Nitschke, R. also contributed to this column.
po_nahco3
Organic P measured in Extract which was shaken in 25ml NaHCO3 for 16hrs
Unit: µg/g
Data group: Phosphorus
Values
11.51039
11.171895
11.64288
11.48501
10.05394
* Nitschke, R. also contributed to this column.
pi_naoh
Inorganic P measured in Extract which was shaken in 25ml NaOH for 16hrs
Unit: µg/g
Data group: Phosphorus
Values
10.26119
11.74294
11.85416
11.514195
11.74827
* Nitschke, R. also contributed to this column.
po_naoh
Organic P measured in Extract which was shaken in 25ml NaOH for 16hrs
Unit: µg/g
Data group: Phosphorus
Values
106.10497
115.79262
115.302405
116.89179000000001
113.71524000000001
* Nitschke, R. also contributed to this column.
pi_naoh_s
Inorganic P measured in Extract which was sonicated in 20ml NaOH for 20min
Unit: µg/g
Data group: Phosphorus
Values
10.44407
13.93064
10.96644
10.96287
12.75446
* Nitschke, R. also contributed to this column.
po_naoh_s
Organic P measured in Extract which was sonicated in 20ml NaOH for 20min
Unit: µg/g
Data group: Phosphorus
Values
10.78425
10.96693
10.13137
10.452480000000001
10.16419
* Nitschke, R. also contributed to this column.
pi_1mhcl
Inorganic P extracted with 20ml 1m HCL for 16hrs
Unit: µg/g
Data group: Phosphorus
Values
0.03783
0.05758
0
0.04705
0.00961
* Nitschke, R. also contributed to this column.
pi_hcl_conc
Inorganic P measured in Extract which was cooked with 10ml concentrated HCL at 85°C for 20min, after that added an extra 5ml concentrated HCL
Unit: µg/g
Data group: Phosphorus
Values
111.232295
101.46147
103.93327
109.59374
107.664285
* Nitschke, R. also contributed to this column.
po_hcl_conc
Organic P measured in Extract which was cooked with 10ml concentrated HCL at 85°C for 20min, after that added an extra 5ml concentrated HCL
Unit: µg/g
Data group: Phosphorus
Values
10.582399999999993
0.32626999999999384
0
10.602339999999998
10.533355000000029
* Nitschke, R. also contributed to this column.
tp_residual
Total residual P extracted with HNO3-Pressure-Extraction method
Unit: µg/g
Data group: Phosphorus
Values
107.51767
120.62321
104.48348
120.726495
165.78559
* Nitschke, R. also contributed to this column.
tp_initial
Total P after digestion with concentrated nitric acid; 400 mg +3 ml HNO3, 8h 190°C under pressure
Unit: µg/g
Data group: Phosphorus
Values
235.81935
261.92293333333333
261.0073
247.29925
254.24915