Elevated CO2 temporally enhances phosphorus immobilization in the rhizosphere of wheat and chickpea

Jin, J. and Tang, C. and Armstrong, R. and Butterly, C. and Sale, P. (2012) Elevated CO2 temporally enhances phosphorus immobilization in the rhizosphere of wheat and chickpea. Plant and Soil. pp. 1-14.

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Aims The efficient management of phosphorus (P) in cropping systems remains a challenge due to climate change. We tested how plant species access P pools in soils of varying P status (Olsen-P 3.2–17.6 mg kg−1), under elevated atmosphere CO2 (eCO2). Methods Chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) plants were grown in rhizo-boxes containing Vertosol or Calcarosol soil, with two contrasting P fertilizer histories for each soil, and exposed to ambient (380 ppm) or eCO2 (700 ppm) for 6 weeks. Results The NaHCO3-extractable inorganic P (Pi) in the rhizosphere was depleted by both wheat and chickpea in all soils, but was not significantly affected by CO2 treatment. However, NaHCO3-extractable organic P (Po) accumulated, especially under eCO2 in soils with high P status. The NaOH-extractable Po under eCO2 accumulated only in the Vertosol with high P status. Crop species did not exhibit different eCO2-triggered capabilities to access any P pool in either soil, though wheat depleted NaHCO3-Pi and NaOH-Pi in the rhizosphere more than chickpea. Elevated CO2 increased microbial biomass C in the rhizosphere by an average of 21 %. Moreover, the size in Po fractions correlated with microbial C but not with rhizosphere pH or phosphatase activity. Conclusion Elevated CO2 increased microbial biomass in the rhizosphere which in turn temporally immobilized P. This P immobilization was greater in soils with high than low P availability.

Item Type: Article
Uncontrolled Keywords: Climate change . Elevated CO2 . Microbial biomass C . P fractions . Phosphatase . Rhizosphere acidification
Author Affiliation: La Trobe University, Melbourne Campus,Chinese Academy of Sciences, Harbin, 150081, China, Department of Primary Industries, PMB 260, Horsham, VIC, 3401, Australia
Subjects: Soil Science and Microbiology
Plant Physiology and Biochemistry > Biochemistry
Divisions: Chickpea
Depositing User: Mr. SanatKumar Behera
Date Deposited: 10 Nov 2012 10:19
Last Modified: 10 Nov 2012 10:19
Official URL: http://dx.doi.org/10.1007/s11104-012-1516-9
URI: http://eprints.icrisat.ac.in/id/eprint/8732

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