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Microbially-mediated P fluxes in calcareous soils as a function of water-extractable phosphate

Schneider, Kimberly D.; Voroney, R. Paul; Lynch, Derek H.; Oberson, Astrid; Frossard, Emmanuel and Bünemann, Else K. (2017) Microbially-mediated P fluxes in calcareous soils as a function of water-extractable phosphate. Soil Biology and Biochemistry, 106, pp. 51-60.

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Online at: http://www.sciencedirect.com/science/article/pii/S0038071716307866

Summary

Soil phosphorus (P) tests are designed to indicate plant-available inorganic orthophosphate (Pi), but fail to account for Pi that may become available through organic phosphorus (Po) mineralization. This P source may be especially important in soils with low concentrations of solution and labile Pi. We assessed gross Po mineralization and immobilization using labeling with 33P in four calcareous Alfisols with varying concentrations of Olsen soil test P that were collected from forage fields of dairy farms in Ontario, Canada. Rapid microbial 33P uptake during incubation was found for the soils with the lowest available Pi as indicated by both Olsen soil test P and water-extractable Pi. The tracer incorporation into microbial P after 8 days ranged from 7 to 44% of applied 33P and was negatively related to water-extractable Pi following a power-type relationship. As concentrations of microbial P were similar in all soils, this suggests faster turnover of P in the microbial biomass at water-extractable Pi below 0.1 mg P kg−1 soil. Daily gross Po mineralization rates ranged from 0.2 to 2.8 mg P kg−1 soil d−1 and contributed 7–56% of the isotopically-exchangeable P in 8 days. Based on these findings, microbial processes have the potential to make a significant contribution to forage P nutrition.


EPrint Type:Journal paper
Keywords:Organic phosphorus mineralization, Isotopic dilution method, 33P, Available phosphorus, Perennial forage, Microbial P turnover, Department of Soil Sciences, Soil Quality and Functions
Subjects: Soil > Soil quality
Environmental aspects
Research affiliation: Switzerland > FiBL - Research Institute of Organic Agriculture Switzerland > Soil Sciences
Switzerland > ETHZ - Agrarwissenschaften
ISSN:0038-0717
DOI:https://doi.org/10.1016/j.soilbio.2016.12.016
Related Links:http://www.fibl.org/en/switzerland/research/soil-sciences/soil-quality-and-functions.html
Deposited By: Forschungsinstitut für biologischen Landbau, FiBL
ID Code:32322
Deposited On:13 Nov 2017 12:20
Last Modified:13 Nov 2017 12:20
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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