La Trobe
2018 Wang & Tang Ann Bot 121,143.pdf (662.2 kB)

The role of rhizosphere pH in regulating the rhizosphere priming effect and implications for the availability of soil-derived nitrogen to plants

Download (662.2 kB)
journal contribution
posted on 07.01.2021, 02:56 by Xiaojuan Wang, Caixian Tang
© The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

Background and Aims A comprehensive understanding of the rhizosphere priming effect (RPE) on the decomposition of soil organic carbon (SOC) requires an integration of many factors. It is unclear how N forminduced change in soil pH affects the RPE and SOC sequestration. Methods This study compared the change in the RPE under supply of NO3-N and NH4-N. The effect of the RPE on the mineralization of soil N and hence its availability to plant and microbes was also examined using a 15N-labelled N source. Key Results The supply of NH4-N decreased rhizosphere pH by 0.16-0.38 units, and resulted in a decreased or negative RPE. In contrast, NO3-N nutrition increased rhizosphere pH by 0.19-0.78 units, and led to a persistently positive RPE. The amounts of rhizosphere-primed C were positively correlated with rhizosphere pH. Rhizosphere pH affected the RPE mainly through influencing microbial biomass, activity and utilization of root exudates, and the availability of SOC to microbes. Furthermore, the amount of rhizosphere primed C correlated negatively with microbial biomass atom% 15N (R2 0.77-0.98, n = 12), suggesting that microbes in the rhizosphere acted as the immediate sink for N released from enhanced SOC decomposition via the RPE. Conclusion N form was an important factor affecting the magnitude and direction of the RPE via its effect on rhizosphere pH. Rhizosphere pH needs to be considered in SOC and RPE modelling.

History

Publication Date

01/01/2018

Journal

Annals of Botany

Volume

121

Issue

1

Pagination

9p. (p. 143-151)

Publisher

Oxford University Press

ISSN

0305-7364

Rights Statement

The Author reserves all moral rights over the deposited text and must be credited if any re-use occurs. Documents deposited in OPAL are the Open Access versions of outputs published elsewhere. Changes resulting from the publishing process may therefore not be reflected in this document. The final published version may be obtained via the publisher’s DOI. Please note that additional copyright and access restrictions may apply to the published version.