Elevated CO2 temporally enhances phosphorus immobilization in the rhizosphere of wheat and chickpea
journal contributionposted on 05.01.2021, 05:00 by Jian Jin, Caixian Tang, Roger Armstrong, C Butterly, Peter Sale
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. © 2012 Springer Science+Business Media Dordrecht.
This research was supported by an Australian Research Council Linkage Project (LP100200757), and utilised the SoilFACE facility of the Department of Primary Industries, Victoria at Horsham. We thank anonymous reviewers for their comments on the manuscript.
JournalPlant and Soil
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Science & TechnologyLife Sciences & BiomedicineAgronomyPlant SciencesSoil ScienceAgricultureClimate changeElevated CO2Microbial biomass CP fractionsPhosphataseRhizosphere acidificationSOIL MICROBIAL BIOMASSTRIFOLIUM-REPENS LLUPINUS-ALBUS L.PHOSPHATASE-ACTIVITYEXTRACTION METHODPROTEOID ROOTSCARBONPLANTACQUISITIONFRACTIONSAgronomy & Agriculture