Soil test measures of available P (Colwell, resin and DGT) compared with plant P uptake using isotope dilution

Mason, Sean; McLaughlin, Michael J.; Johnston, C. D.; McNeill, Ann

doi:10.1007/s11104-013-1833-7

Cited by 53 publications

(34 citation statements)

References 34 publications

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“…Deepest insights in the dynamic aspects of P mobilization and immobilization in soils have been obtained with isotopic dilution techniques (Frossard et al, 2011). It has been shown that batch extracts mobilize P from pools not directly available to plants (Mason et al, 2013;Six et al, 2013). More comparable to the root's approach is to strip phosphate from the solid phase by lowering the soil-solution concentration, which can be achieved by establishing an infinite diffusional sink (Frossard et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Assessment of diffusive phosphate supply in soils by microdialysis

Demand

Schack‐Kirchner

Lang

2017

J. Plant Nutr. Soil Sci.

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Standard procedures to assess P availability in soils are based on batch experiments with various extractants. However, in most soils P nutrition is less limited by bulk stocks but by strong adsorption and transport limitation. The basic principle of root‐phosphate uptake is to strip phosphate locally from the solid phase by forming a radial depletion zone in the soil solution, optionally enhanced by release of mobilizing substances. Microdialysis (MD), a well‐established method in pharmacokinetics, is capable to mimic important characteristics of P root uptake. The sampling is by diffusional exchange through a semipermeable membrane covering the probes with their sub‐mm tubular structure. Additionally, the direct environment of the probe can be chemically modified by adding, e.g., carboxylates to the perfusate. This study is the first approach to test the applicability of MD in assessing plant available phosphate in soils and to develop a framework for its appropriate use.We used MD in stirred solutions to quantify the effect of pumping rate, concomitant ions, and pH value on phosphate recovery. Furthermore, we measured phosphate yield of top‐soil material from a beech forest, a non‐fertilized grassland, and from a fertilized corn field. Three perfusates have been used based on a 1 mM KNO3 solution: pure (1), with 0.1 mM citric acid (2), and with 1 mM citric acid (3). Additionally, a radial diffusion model has been parametrized for the stirred solutions and the beech forest soil.Results from the tests in stirred solutions were in good agreement with reported observations obtained for other ionic species. This shows the principal suitability of the experimental setup for phosphate tests. We observed a significant dependency of phosphate uptake into the MD probes on dialysate pumping rate and on ionic strength of the outside solution. In the soils, we observed uptake rates of the probes between 1.5 × 10−15 and 6.7 × 10−14 mol s−1 cm−1 in case of no citrate addition. Surprisingly, median uptake rates were mostly independent of the bulk soil stocks, but the P‐fertilized soil revealed a strong tailing towards higher values. This indicates the occurrence of hot P spots in soils. Citrate addition increased P yields only in the higher concentration but not in the forest soil. The order of magnitude of MD uptake rates from the soil samples matched root‐length related uptake rates from other studies. The micro‐radial citrate release in MD reflects the processes controlling phosphate mobilization in the rhizosphere better than measurements based on “flooding” of soil samples with citric acid in batch experiments. Important challenges in MD with phosphate are small volumes of dialysate with extremely low concentrations and a high variability of results due to soil heterogeneity and between‐probe variability. We conclude that MD is a promising tool to complement existing P‐analytical procedures, especially when spatial aspects or the release of mobilizing substances are in focus.

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Section: Introductionmentioning

confidence: 99%

Assessment of diffusive phosphate supply in soils by microdialysis

Demand

Schack‐Kirchner

Lang

2017

J. Plant Nutr. Soil Sci.

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“…In the Vertisol, as all the chemical extractions demonstrated, TSP performed best (Xiong et al, 2018a). The superior accuracy of DGT relative to Colwell and anion resin methods in assessing true plant availability of P has been documented before (Mason et al, 2013). The main disadvantage is that it is more labor intensive than traditional wet chemical extractions.…”

Section: Slow Releasersmentioning

confidence: 69%

A Review of the Latest in Phosphorus Fertilizer Technology: Possibilities and Pragmatism

2019

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The development of highly concentrated phosphorus (P) fertilizers, such as triple superphosphate, by the Tennessee Valley Authority helped mark the beginning of a revolution in the way we manage food crop nutrition. Since then, scientists, with the help of farmers, have made great advancements in the understanding of P fate and transport across many environments but largely have failed to produce a new generation of products and/or application techniques that are widely accepted and that vastly improve plant acquisition efficiency. Under certain conditions, important advancements have been made. For example, applying liquid formulations of phosphates in lieu of dry granules in some highly calcareous soils has dramatically reduced precipitation as sparingly soluble calcium phosphate minerals, but other attempts, such as the co‐application of humic substances, sorption to layered double hydroxides, or use of nanoparticles, have not generated the kind of results necessary to continue economically increasing crop yields without further environmental cost. New sources of fertility will need to be affordable to produce, transport, and furnish P to soil solution in a manner well synchronized with crop demand. This paper provides a review of recent literature on cutting‐edge phosphorus fertilizer technology. The goal is that this synthesis will be used as a starting point from which a larger discussion on responsible nutrient management and increased P use efficiency research can be built. Core Ideas Reaction with some soil constituents limits P availability and crop yield. A variety of approaches to improve fertilizer use efficiency are being explored. Ideally, P availability should be well synchronized to crop demand. More innovation along with mechanistic and field‐scale trials is required.

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“…There are only a few studies that use the ratio of specific activities in plants and soils, but none of them pertaining to Cd. According to Mason et al (2013) and Muraoka et al (1983), a ratio for plant/ extractants around 0.60 could be considered efficient. Plants can serve as reference tools for assessing nutrient levels in the soil, thus reflecting actual nutrient availability.…”

Section: Extractant Effectiveness and The L Ratiomentioning

confidence: 99%