Generating a high‐resolution map of labile soil phosphorus using ferrous oxide–impregnated paper combined with scanning electron microscopy

Atmospheric deposition of desert dust and ash from wildfires are recognised as major suppliers of phosphorus (P) to soils in many terrestrial ecosystems. The biological effects of desert dust and fire ash P depend on their interactions with the receiving soils. However, the chemical processes and environmental conditions that control dust and ash P bioavailability post deposition are unknown. Soil and rhizospheric pH and organic exudates are acknowledged as central parameters that control soil P bioavailability. Here we performed a series of in‐vitro incubation experiments to study their effects on P solubility of various desert dust and fire ash samples. Then, we tested the dust and ash P solubility that were added to acidic and alkaline soils. Our results show that dust P solubility gradually increases by a few orders of magnitude as pH decreases from 7 to 2.5 and also with increased concentrations of oxalic and malic acids, two ubiquitous P solubilising organic exudates in soils. In both cases, the increase in dust P solubility occurs mainly by dissolving P from insoluble Ca‐P minerals such as apatite, the major P bearing mineral in desert dust. P solubility of fire ash was dramatically higher than that of desert dust but showed the same pattern of a gradual increase with decreasing pH or with increasing concentrations of oxalic and malic acids. When the dust was suspended with soils, extractable P level was ~10 times higher in alkaline soil than acidic soil despite the lower pH of the later, probably due to the strong P sorption capacity of the acidic soils. On the contrary, when fire ash was suspended, extractable P in the acidic soil was higher than that of the alkaline soil indicating substantial variation in P forms. Overall, our results indicate that the bioavailability of P from desert dust and fire ash is largely controlled by environmental and chemical factors in the receiving soils. Highlights Atmospheric deposition from desert dust and fire ash is a major phosphorus source to soils. However, the actual bioavailability of dust and ash P post deposition is unknown. Soil pH, organic acids concentrations and P sorption capacity controls dust and ash bioavailability. The bioavailability of atmospheric P is controlled by environmental factors in the receiving soils.

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“…Properties of the soils are presented in Table S3. More details on the soils can be found in Li and Erel (Li & Erel, 2020).…”

Section: Methodsmentioning

confidence: 99%

Chemical processes in receiving soils accelerate solubilisation of phosphorus from desert dust and fire ash

Tiwari

Erel

Gross

2022

European J Soil Science

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Methods for assessing laterally-resolved distribution, speciation and bioavailability of phosphorus in soils

Bom

Kopittke

Raymond

et al. 2022

Rev Environ Sci Biotechnol

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Comparison of Methods for Mapping Rhizosphere Processes in the Context of Their Surrounding Root and Soil Environments

Moran

McGrath

2021

BioTechniques

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The rhizosphere embodies a complex biogeochemical zone with enhanced rates of nutrient exchange between plants, soil, and microbial communities. Understanding controls on rhizosphere dynamics is critical to support emerging concepts including rhizosphere engineering and reduced dependence on chemical fertilizers which have direct application to food production, increased biofuel generation, and habitat restoration efforts. Yet, its fine spatial scale and complex interactions between geochemical and microbial processes within complex spatiotemporal gradients make the rhizosphere notoriously difficult to study. Emerging instrumentation and methodologies, however, are providing improved resolution to rhizosphere measurements and helping to address critical knowledge gaps in rhizosphere function, ecology, and establishment. Here, we examine recent advances in analysis techniques and the resulting potential for improved understanding of rhizosphere function.

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Generating a high‐resolution map of labile soil phosphorus using ferrous oxide–impregnated paper combined with scanning electron microscopy

Cited by 3 publications

References 42 publications

Chemical processes in receiving soils accelerate solubilisation of phosphorus from desert dust and fire ash

Chemical processes in receiving soils accelerate solubilisation of phosphorus from desert dust and fire ash

Methods for assessing laterally-resolved distribution, speciation and bioavailability of phosphorus in soils

Comparison of Methods for Mapping Rhizosphere Processes in the Context of Their Surrounding Root and Soil Environments

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