Toward a Global Model for Soil Inorganic Phosphorus Dynamics: Dependence of Exchange Kinetics and Soil Bioavailability on Soil Physicochemical Properties
The representation of phosphorus (P) cycling in global land models remains quite simplistic, particularly on soil inorganic phosphorus. For example, sorption and desorption remain unresolved and their dependence on soil physical and chemical properties is ignored. Empirical parameter values are usua...
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| Vydané v: | Global biogeochemical cycles Ročník 36; číslo 3; s. e2021GB007061 - n/a |
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| Hlavní autori: | , , , , , |
| Médium: | Journal Article |
| Jazyk: | English |
| Vydavateľské údaje: |
Washington
Blackwell Publishing Ltd
01.03.2022
John Wiley and Sons Inc |
| Predmet: | |
| ISSN: | 0886-6236, 1944-9224 |
| On-line prístup: | Získať plný text |
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| Shrnutí: | The representation of phosphorus (P) cycling in global land models remains quite simplistic, particularly on soil inorganic phosphorus. For example, sorption and desorption remain unresolved and their dependence on soil physical and chemical properties is ignored. Empirical parameter values are usually based on expert knowledge or data from few sites with debatable global representativeness in most global land models. To overcome these issues, we compiled from data of inorganic soil P fractions and calculated the fraction of added P remaining in soil solution over time of 147 soil samples to optimize three parameters in a model of soil inorganic P dynamics. The calibrated model performed well (r2 > 0.7 for 122 soil samples). Model parameters vary by several orders of magnitude, and correlate with soil P fractions of different inorganic pools, soil organic carbon and oxalate extractable metal oxide concentrations among the soil samples. The modeled bioavailability of soil P depends on, not only, the desorption rates of labile and sorbed pool, inorganic phosphorus fractions, the slope of P sorbed against solution P concentration, but also on the ability of biological uptake to deplete solution P concentration and the time scale. The model together with the empirical relationships of model parameters on soil properties can be used to quantify bioavailability of soil inorganic P on various timescale especially when coupled within global land models.
Plain Language Summary
Phosphorus (P) is a major nutrient limiting the productivity of many terrestrial ecosystems. About 20%–60% of soil phosphorus is in inorganic form, and most inorganic soil P is sorbed or fixed on soil particles, leaving a small fraction (<1%) in soil solution available for direct uptake by plants. Sorption and desorption control inorganic P in solution and vary significantly with soil properties. However, sorption and desorption are not explicitly represented in most global land models. This study developed and calibrated a model of inorganic P dynamics using the observations from 147 soils worldwide. We found that the parameters in the model can vary by several orders of magnitude, and that a significant proportion of those variations can be explained by soil chemical properties, particularly soil P fractions, oxalate extractable metal oxide and soil organic carbon concentrations. The model and empirical relationships between model parameters and soil properties as developed in this study can be used to improve the representation of P cycle in land models.
Key Points
We developed and calibrated a model of soil inorganic P dynamics using the measured soil Phosphorus (P) fractions and isotopic exchange kinetics of 147 soils
We derived empirical relationships between model parameters and some soil chemical properties
Soil P bioavailability depends on soil P fractions, solution P concentration, desorption rate constants and the time scale |
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| Bibliografia: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23 |
| ISSN: | 0886-6236 1944-9224 |
| DOI: | 10.1029/2021GB007061 |