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Phosphorus in the coarse soil fraction is related to soil organic phosphorus mineralization measured by isotopic dilution

Wyngaard, Nicolas; Cabrera, Miguel Lorenzo; Jarosch, Klaus A. and Bünemann, Else Katrin (2016) Phosphorus in the coarse soil fraction is related to soil organic phosphorus mineralization measured by isotopic dilution. Soil Biology and Biochemistry, 96, pp. 107-118.

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Online at: http://www.sciencedirect.com/science/article/pii/S0038071716000377

Summary

A sound prediction of soil organic phosphorus (Po) mineralization would be helpful to improve fertilizer recommendations. However, in most mineral soils expensive and time consuming isotopic dilution experiments are required to assess Po mineralization. A proposed method to estimate Po mineralization is the quantification of P in the coarse fraction (CF, >53 μm) of the soil. The aim of this study was to evaluate if P in the CF can effectively predict Po mineralization. Soil samples from three North American long-term arable field experiments (>10 years) with different textures (sand content 15–82%) and different fertilization treatments (non-P-fertilized, mineral P fertilizer, poultry litter) were analyzed. Soil samples were physically fractioned into CF and fine fraction (FF, <53 μm). Total P (Pt), Po, and total carbon (Ct) were determined in each fraction. Gross and net Po mineralization rates as well as soil respiration were determined in a 13-day-incubation experiment. The cumulative gross Po mineralization over 13 days ranged from 8.3 to 38.6 mg P kg−1, while Pt in CF varied between 9.7 and 90.7 mg P kg−1 and Po in CF between 6.1 and 17.7 mg kg−1. No association between Pt in CF and gross or net mineralized Po was observed. However, a significant linear relationship between Po in CF and net (R2:0.68, p < 0.01) and gross mineralized Po (R2:0.72, p < 0.01) was observed after 6 days and 13 days of incubation. Additionally, gross and net mineralized Po could also be predicted from C respiration, and these models were significantly improved by incorporating the Ct:Po ratio of the CF. Our results suggest that the quantification of Po in the CF as well as the measurement of respiration corrected by the Ct:Po ratio of the CF are promising non-isotopic indicators of Po mineralization rates.


EPrint Type:Journal paper
Keywords:Organic phosphorus, Mineralization, Isotopic dilution, Poultry litter, Mineral fertilizer, Physical fractionation, Department of Soil Sciences, Soil Quality and Functions
Subjects: Soil > Soil quality
Research affiliation: Switzerland > FiBL - Research Institute of Organic Agriculture Switzerland > Soil Sciences
Argentina
USA > Other organizations
Switzerland > Other organizations
ISSN:0038-0717
DOI:https://doi.org/10.1016/j.soilbio.2016.01.022
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:32310
Deposited On:13 Nov 2017 11:19
Last Modified:13 Nov 2017 11:19
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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