Phosphorus dynamics in a tropical forest soil restored after strip mining

Alister V Spain,Michael Ridd,Timothy I Mclaren,Mark Tibbett

doi:10.1007/s11104-018-3668-8

Alister V Spain, Michael Ridd + Show 2 more

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https://doi.org/10.1007/s11104-018-3668-8

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Abstract

Background and aimsWe hypothesized that successful early ecosystem and soil development in these P-deficient soil materials will initially depend on effective re-establishment of P storage and cycling through organic matter. This hypothesis was tested in a 26-year chronosequence of seven lightly fertilized, oxidic soil materials restored to eucalypt forest communities after bauxite mining.MethodsTotal P (Pt) status, Hedley P fractions and partial chemical speciation (NaOH-EDTA extraction and analysed using solution 31P NMR spectroscopy) were determined in the restored soils.ResultsConcentrations of Pt and most Hedley fractions changed with restoration period, declined with depth and were strongly positively correlated with C and N concentrations. Biological P dominated the Labile and Intermediate P fractions while Long-term P was dominantly inorganic. Organic P concentrations in NaOH-EDTA extracts and their chemical natures were similar in restored and unburned native forest sites. Phosphomonoesters were the dominant class of organic P.ConclusionsSurprisingly rapid P accretion and fractional changes occurred over 26 years, largely in the surface soils and closely associated with organic matter status. Alkaline hydrolysis products of phosphodiesters and pyrophosphate indicated the importance of microbial P cycling. The important consequences for long-term ecosystem development and biological diversity require further study.

Highlights

Phosphorus (P) is an essential element that widely conditions biological processes in all earth surface environments (Elser et al 2007), including net primary production (Cleveland et al 2011)
Concentrations of Pt and most Hedley fractions changed with restoration period, declined with depth and were strongly positively correlated with C and N concentrations
Surprisingly rapid P accretion and fractional changes occurred over 26 years, largely in the surface soils and closely associated with organic matter status

Summary

Introduction

Phosphorus (P) is an essential element that widely conditions biological processes in all earth surface environments (Elser et al 2007), including net primary production (Cleveland et al 2011). Retention of P in these soils is high (IUSS Working Group WRM 2015; Short et al 2000, 2007) and in natural environments P supply for the support of biological activity is characteristically constrained (Lang et al 2016) In such environments, maintenance of P supply occurs largely through biological recycling, desorption and diffusion from poorlyavailable forms, possibly limited aerial accession (Reed et al 2011; Tipping et al 2014) and, in managed environments, from fertilizer inputs. We hypothesized that successful early ecosystem and soil development in these Pdeficient soil materials will initially depend on effective re-establishment of P storage and cycling through organic matter This hypothesis was tested in a 26-year chronosequence of seven lightly fertilized, oxidic soil materials restored to eucalypt forest communities after bauxite mining. Spain UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia

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