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Comparing measures for determination of phosphorus saturation as a method to estimate dissolved P in soil solution

Blombäck, Karin and Bolster, Carl H. and Lindsjö, Anders and Hesse, Kathrin and Linefur, Helena and Parvage, Masud (2021). Comparing measures for determination of phosphorus saturation as a method to estimate dissolved P in soil solution. Geoderma. 383 , 114708
[Research article]

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Abstract

In response to concerns over the translocation of P from soils to P-sensitive water bodies, there is high demand for developing simple indicators for evaluating a soil's risk of releasing P into solution. Many studies have shown that the degree of soil phosphorus saturation (DPS), calculated as the ratio of soil P concentration to soil P sorption capacity (PSC), is good predictor of a soil's risk of releasing Pin solution. In this study we compared four different DPS indices in how well they predicted dissolved P following extraction with either a 0.01 M caCl2 (P-caCl2) solution or deionized water (P-w). The first two indices were calculated from the ratio of extractable P to extractable Al and Fe using either acid ammonium oxalate (Al-OX + Fe-OX) or ammonium lactate solutions (Al-AL + Fe-AL). The second two DPS indices were calculated from the ratio of either Olsen-extractable P or AL-extractable P with sorption capacity estimated from the single point P sorption index (PSI). On a subset of 11 soils, we compared the different methods for estimating PSC with fitted Langmuir sorption maximum (Smax) using data from complete sorption isotherms. Both (Al-OX + Fe-OX) and PSI were well correlated with Smax and hence regarded as good estimates for P sorption capacity. Conversely, (Al-AL + Fe-AL) was not significantly correlated with Smax. P saturation calculated from PSI together with P-AL or P-O1s predicted P-caCl2 and P-w, best, whereas P saturation calculated from ammonium oxalate predicted P-caCl2 and P-w the least. We did not find notable improvements in the regression models when we added a second explanatory variable (clay content, pH or total carbon) to the models. Our results show that multiple measures of P saturation provide similar predictions of a soils potential for releasing dissolved P into soil solution. This provides flexibility in how P saturation indices are calculated to identify leaching prone hotspots.

Authors/Creators:Blombäck, Karin and Bolster, Carl H. and Lindsjö, Anders and Hesse, Kathrin and Linefur, Helena and Parvage, Masud
Title:Comparing measures for determination of phosphorus saturation as a method to estimate dissolved P in soil solution
Series Name/Journal:Geoderma
Year of publishing :2021
Volume:383
Article number:114708
Number of Pages:10
Publisher:ELSEVIER
ISSN:0016-7061
Language:English
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Keywords:Degree of phosphorus saturation, Phosphorus sorption capacity, Ammonium lactate extraction, Ammonium oxalate extraction, Sorption isotherms, PSI
URN:NBN:urn:nbn:se:slu:epsilon-p-109725
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-109725
Additional ID:
Type of IDID
DOI10.1016/j.geoderma.2020.114708
Web of Science (WoS)000590747800002
ID Code:21226
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: SLUpub Connector
Deposited On:14 Jan 2021 14:23
Metadata Last Modified:14 Jan 2021 14:31

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