Relationships of phosphorus fractions to organic carbon content in surface soils in mature subtropical forests, Dinghushan, China

Abstract

Abstract. Exploring the relationship between the accumulation of soil organic carbon (C) and the form and availability of soil phosphorus (P) is important for improved understanding of soil P availability and its regulation of C storage in forest ecosystems. Here, we investigated the relationships among soil organic C, sequentially extracted P fractions and P sorption index in 32 surface soils (0-0.15 m depth) across eight mature subtropical forests (80-400 years) in Dinghushan, China. Results showed that soil organic P (Po) accounted for 40-63% (mean 54%) of soil total P. Soil organic C was significantly positively correlated with both the content and the percentage of soluble inorganic P (Pi), Al-Po and Fe-Po fractions and the content of the Al-Pi fraction. The content of soil total Po increased significantly with soil organic C, whereas the percentage of soil total Po tended to increase with soil organic C only when soil organic C was low (<30 Mg/ha) but was relatively stable when soil organic C was high (!30 Mg/ha). Moreover, soil organic C was highly correlated with P sorption index. Our results suggest that accumulation of organic C may increase, rather than decrease, the availability of P in surface soil in mature subtropical forests.

Phosphorus availability in relation to soil properties and forest productivity in Pinus sylvestris L. plantations

“…The stable (PHCl conc ) and the organic moderately labile (P o NaOH) fractions were the predominant forms of P in the soils studied as also observed by Turrión et al (2007). The low soil pH in the soils studied is related to the presence of exchangeable Al responsible for the decrease in P solubility and for the increase in the non-labile P pools (Cross and Schlesinger 1995;Hou et al 2014).…”

“…Although the general processes involved in P availability are known, further studies are necessary to clarify the importance of each process on specific ecosystems (Hou et al 2014). For that purpose, the Hedley et al (1982) P sequential fractionation method modified by Tiessen and Moir (1993) was applied in this study.…”

Phosphatase activity in relation to key litter and soil properties in mature subtropical forests in China

“…Inorganic P concentration in the 1.0 M NH 4 Cl extract (soluble Pi) was below the detection limit of the molybdate blue method and was therefore reanalyzed using the malachite green method (Ohno and Zibilske, 1991). Organic P in the 0.1 M NH 4 F (Al-Po) and 0.1 M NaOH (Fe-Po) extracts was calculated as the difference between total P determined after persulfate digestion (Ormaza-González and Statham, 1996) and inorganic P. The soil P fraction data are cited from Hou et al (2014). All data presented in this study are based on an oven-dried weight (65°C for plant materials and 105°C for soil).…”

Plant and soil δ13C and δ15N are linked to community biomass, litter production, and litter turnover rate in mature subtropical forests

“…The high N status was perhaps because of the high atmospheric N deposition (about 40 kg N ha -1 yr -1 ; Huang et al 2012) and the high stand ages, while the low soil P availability might be due to the moderate extent of soil development, relatively low parent rock P concentration, etc. (Hou et al 2012(Hou et al , 2014. Three main explanations have been proposed for the positive effects of soil P availability on plant and soil d 15 N in previous studies (McKee et al 2002;Mori et al 2010;Vitousek 1999).…”

“…Total N of the extract was analysed using a SHIMADZU TOC-VCPH/CPN analyser (Kyoto, Japan). Soil extractable P was calculated as the sum of inorganic P concentration sequentially extracted by 1.0 M NH 4 Cl, 0.1 M NH 4 F, and 0.1 M NaOH, as described in detail by Hou et al (2014).…”