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.

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.

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

Samples were collected from 2010 to 2011.

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).