Mike John McLaughlin

Mike John McLaughlin
University of Adelaide · School of Earth and Environmental Sciences

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569
Publications
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Publications

Publications (569)
Article
Hypothesis Layered double hydroxide (LDH) loaded with orthophosphate (PO4) are suggested as slow-release P fertilizers. However, PO4-LDHs have a low maximal P content, related to high charge HPO4²⁻/PO4³⁻ anions occupying the anion exchange capacity (AEC) of LDHs. We postulate that the P content of LDHs can be enhanced by exchanging them with polyme...
Article
Full-text available
Microbial inoculants containing arbuscular mycorrhizal (AM) fungi are potential tools in increasing the sustainability of our food production systems. Given the demand for sustainable agriculture, the production of such inoculants has potential economic value and has resulted in a variety of commercial inoculants currently being advertised. However...
Article
Agricultural soil (Ap-horizon, 0–20 cm) samples were collected from 33 European countries as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soilmapping project. The Mg data derived from total concentrations (XRF) and two acid digestion methods, aqua regia (AR) and Mobile Metal Ion (MMI®), were used to provide an overv...
Article
Background Globally and at the European Union level there are mounting concerns regarding nitrogen (N) losses from agricultural systems and pressure to reduce N losses to water and air. Suboptimal plant sulfur (S) availability can reduce plant N efficiency and thereby increase N loss potential. Climate change action demands lower sulfur dioxide emi...
Article
The effect of soluble cations on sorption in soils of a range of anionic PFAS is not well studied. We investigated the role of three common cations (Na⁺, Ca²⁺, and Mg²⁺) at varying solution concentrations on the sorption coefficients (Kd) of 18 anionic PFAS in two contrasting soils. The effective charge of the soil suspension (Zeta potential) becam...
Article
Arbuscular mycorrhizal fungi (AMF) are plant symbionts that promote plant growth and provide important plant and ecosystem functions. These abilities have great economical potential which has resulted in an increasing number of commercially available AMF inoculants. Here, we present the results of a global study in which we evaluate the effectivene...
Article
Droughts are increasing in frequency and severity in many regions of the world and there are uncertainties how recurrent drought will impact acid sulfate soils, which can undergo extreme and persistent acidification (pH < 4) following oxidation. Using column experiments, we induced a 9 week drought/drying and 9 week rewetting phase in two acid sulf...
Article
Achieving sustainable agricultural development requires the efficient use of nutrient resources for crop production. Recovering nutrients from animal manures may play a key role in achieving this. Animal manures typically have low nutrient concentrations, and in ratios that are often not ideal for balanced crop nutrition. Here, combinations of orga...
Article
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Foliar selenium (Se) fertilisation has been shown to be more efficient than soil-applied fertilisation, but the dynamics of absorption and translocation have not yet been explored. An experiment was undertaken to investigate time-dependent changes in the absorption, transformation, and distribution of Se in wheat when ⁷⁷ Se-enriched sodium selenate...
Article
The use of composts and potting mixes in food production systems is a promising way to counteract the effects of soil degradation and allows crop growth in soilless culture systems. Arbuscular mycorrhizal fungi (AMF) are a well-studied group of beneficial plant symbionts that have been shown to provide important ecosystem services. This study analy...
Article
There is a paucity of data on the state of urban agriculture soils. In order to develop efficient management practices, it is necessary to understand the seasonal dynamics of the soil health of these systems. This study sampled two community gardens, and one commercial, urban agriculture site on a monthly basis over the span of one year. The dynami...
Article
A very small amount of applied zinc (Zn) is taken up by crops, resulting in low recovery by plants. Adding elemental sulphur to zinc oxide (ZnO) fertiliser could improve Zn solubilisation and exert a higher residual effect on crops than soluble Zn sources. We produced an isotopically labelled Zn-elemental sulphur fertiliser and evaluated its perfor...
Article
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Aims Zinc biofortification through agronomic and/or genetic approaches is one of the strategies to enrich food with this essential element to fulfil nutritional requirements in poor diets. This study aimed to unravel the physiological basis of differential tuber-Zn concentration between potato cultivars and to identify the major source(s) of Zn to...
Article
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In previous studies, we assessed sulfur (S) uptake by crops from elemental S (ES) and sulfate-S (SO 4 -S) in S-fortified monoammonium phosphate fertilizers over two years. The recovery by the crop ranged from 16 to 28% for ES and from 9 to 86% for SO 4 -S. Here, we used a model which takes into account organic S cycling, SO 4 -S leaching and ES oxi...
Article
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Losses of phosphorus (P) from fertilized fields may result in degradation of water quality. Various initiatives are under evaluation to minimize water contamination, including the adoption of less soluble or coated P fertilizer formulations aiming to mitigate losses of P in runoff. Field‐based rainfall simulators are traditionally used to evaluate...
Article
Elemental sulfur (ES) is commonly used as a fertilizer S source, but needs to be oxidized to sulfate to become plant‐available. We assessed how placement (surface applied or incorporated in soil) affects the oxidation of ES‐containing fertilizers. The fertilizers included an ES powder, a suspension of biogenic ES particles and three granular fertil...
Article
The application of boron (B) fertilizers is challenging due to the high solubility of commonly used B compounds, the small requirement by crops, and the narrow range between toxicity and deficiency levels for plants. The application of a B-only fertilizer without a macronutrient carrier is inefficient due to the high cost of double handling and the...
Article
Previous biofortification studies have established that the residual effect of added selenium (Se) fertilisers on second-season crops is minimal. To explore the fate of exogenous Se in soil, chemical and biological methods were employed to assess the change in Se bioavailability with time. Eight soils varying in physicochemical properties were spik...
Article
This study investigated the potential aging and plant bioaccumulation of three perfluoroalkyl acids (PFAAs), perfluorosulphonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulphonic acid (PFHxS) in 20 soils over a six-month period. Sorption coefficients (Log Kd) ranged from 0.13–1.28 for PFHxS, 0.17–1.06 for PFOA and 0.98–2.03 for...
Article
Jarosite (KFe3(SO4)2(OH)6) is a common secondary reaction product of iron sulfide oxidation and can pose a considerable risk to soil and water quality. The overarching objective of this study was to explore the possibility of employing passivation-based treatments to mitigate the risks associated with jarosite-rich materials by investigating the al...
Article
Persistent use of aqueous film-forming foams containing poly- and perfluoroalkyl substances (PFASs) in firefighting has led to severe contamination of soil and aquifers at training sites, which makes remediation of such sites a necessity. We investigated the persistence of binding of PFASs to a mixed-mode remediation agent including repeated leachi...
Article
Agricultural soil (Ap-horizon, 0–20 cm) samples were collected from 33 European countries as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soilmapping project. The Mg data derived from total concentrations (XRF) and two acid digestion methods, aqua regia (AR) and Mobile Metal Ion (MMI® ), were used to provide an over...
Article
The global problem of groundwater being contaminated with per- and polyfluoroalkyl substances (PFASs) originating from highly contaminated soils has created a need to remediate these locations. In situ immobilisation of PFASs in soil by applying sorbents is often a preferred low-cost technique to reduce their mobility and leaching to groundwater, b...
Chapter
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Cadmium (Cd) is a naturally occurring element present in all soils from both geogenic and anthropogenic sources. The primary risk pathway to humans is exposure through dietary intake in foods and by inhalation through smoking, with the target affected organ being the kidney. In developed countries, Cd intakes by populations are below levels of conc...
Article
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The aim of this study was to assess the soil–water partitioning behavior of a wider range of per- and polyfluoroalkyl substances (PFASs) onto soils covering diverse soil properties. The PFASs studied include perfluoroalkyl carboxylates (PFCAs), perfluoroalkane sulfonates (PFSAs), fluorotelomer sulfonates (FTSs), nonionic perfluoroalkane sulfonamide...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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Field trials with labeled fertilizers can be used to provide information on fertilizer efficiency, residual value, and nutrient fate. We assessed the uptake from elemental S (ES) and sulfate S (SO4-S) in S-fortified monoammonium phosphate fertilizers by various crops at three sites in Argentina, Brazil, and Canada. The S sources were labeled with 3...
Article
The integration of urban green spaces into modern city planning is seen as a promising tool to offset the drawbacks of ever-expanding cities. Urban agriculture is a common method to implement such strategies and to increase urban sustainability with a special focus on food security. Due to their location, urban farms are highly influenced by past a...
Article
Jarosite (KFe3(SO4)(OH)6) is known to play a key role in perpetuating chemically aggressive properties in acid sulfate soils with sulfuric material (pH < 4) – primarily through the release of retained acidity. The purpose of this study was to describe: (i) the composition of jarosite-rich segregations handpicked from sulfuric material and (ii) the...
Article
A new strategy to produce phosphate (P) fertilisers with both fast and slowly soluble P by compaction method to produce composite products is presented. This unique composition is created by combining mono-ammonium phosphate (MAP) as a highly soluble P nutrient source, with a commercially available slow-release P such as struvite (Str) or P-loaded...
Article
Full-text available
Grasslands are a globally important use of land for food and fibre production, which often require the addition of phosphorus (P) fertiliser to maximise plant production. However, a large proportion of the added P can accumulate in pools of poorly available inorganic and organic P in the surface soil layer under grasslands. The aim of this study wa...
Article
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Total Zn in fertilizer is a poor predictor of Zn availability in granular fertilizers. In this study, we compared different extraction methods using Zn fertilizers for which the agronomic effectiveness had previously been determined. Sixteen fertilizers were extracted by eight different procedures using five extractant solutions: water, 1 M ammoniu...
Article
Historically, the chemical nature of organic phosphorus (P) in soil has largely been considered to comprise of recognizable biomolecules that predominantly include inositol phosphates, nucleic acids and phospholipids. However, these forms alone do not explain the existence of, or account for the processes responsible for, a larger pool of “unresolv...
Article
The ability to utilise foliar-applied phosphorus (P) as a strategy to increase the P status and yield of grain crops grown in dryland regions with variable climates is attractive. Several P formulations with varying pH, accompanying cations and adjuvants were tested for their effectiveness as foliar fertilisers for wheat (Triticum aestivum L.) plan...
Article
Full-text available
Increasing the selenium (Se) concentration of staple crops by fertilization is a valuable pathway to increase Se in the human diet, thus preventing Se deficiency. A pot trial was set up to investigate whether the application of 3.33 µg kg−1 of Se (equivalent to 10 g ha−1) to wheat can be made more efficient by its co-application with macronutrient...
Article
The graphene oxide (GO) due to its exceptional structure, physicochemical and mechanical properties is a very attractive material for industry application. Even though, the unique properties of GO (e.g. structure, size, shape, etc.) make the risk assessment of this nanomaterial very challenging in comparison with conventional ecotoxicology studies...
Article
The demand for ‘high-tech’ element resources (e.g., rare earth elements, lithium, platinum group elements) has increased with their continued consumption in developed countries and the emergence of developing economies. To provide a sound knowledge base for future generations, it is necessary to identify the spatial distribution of critical element...
Article
The sorption behaviour of three perfluoroalkyl substances (PFASs), namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS), was determined on 28 tropical soils. Tropical soils are often highly weathered, richer in sesquioxides than temperate soils and may contain variable charge minerals....
Article
Abstract Zinc (Zn) is a limiting nutrient in soils for both plant yield and Zn nutrition. Soil Zn deficiency can be corrected by the application of Zn fertilisers. Novel formulations of Zn fertiliser are being developed using loaded graphene oxide (GO) sheets, but plant trials are limited. Barley (Hordeum vulgare) and Medicago (Medicago truncatula...
Article
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Introduction: Foliar applied phosphorus (P) has the potential to provide a more tactical approach to P fertilization that could enhance P use efficiency. The aims of this study were to investigate the influence of adjuvant choice and application timing of foliar applied phosphoric acid on leaf wettability, foliar uptake, translocation, and grain yi...
Article
Granular fertilizers should have appropriate mechanical strength to resist significant fracturing during the handling and storage process. Graphene (GN) has the potential to act as a high-performance reinforcement for different composites. This paper provides a comprehensive study of the influence of GN concentration on the crushing strength of two...
Article
Full-text available
Since its discovery in 1669, phosphorus (P) in the form of fertilizer has become an essential input for many agroecosystems. By introducing a concentrated P source, fertilizers increase short-term P export potential soon after their application and longer-term export potential by increasing soil fertility (legacy P). The 4R concept was developed to...
Article
Graphene-based nanomaterials (GNMs) have been touted as miracle materials due to their extraordinary properties that can benefit many industries, including in agriculture and for environmental remediation. While improvement in nutrient delivery and the ability to adsorb environmental contaminants have been demonstrated, what happens to GNMs in soil...
Presentation
Full-text available
Fertiliser granules need to have sufficient mechanical strength to resist fracturing and creation of dust during handling, storage and spreading. Graphene (GN) and its oxidized form graphene oxide (GO) are new materials with distinctive properties such as unique 2D structures, high surface area and exceptional mechanical properties. Graphene is the...
Article
In recent years, innovations in fertilizer research have principally been in the design of products to supply more timely plant nutrients and mitigate detrimental losses to the environment. In the development of these fertilizers, a laboratory method to comparatively screen a large number of formulations for the rate of nutrient release is a critic...
Article
Current commercially available phosphorus (P) fertilisers, which are highly soluble salts, are susceptible to surface runoff to waterways, and leaching to groundwaters where soils are light/medium textured. Here, we report the synthesis of a graphene oxide (GO)/iron (GO-Fe) composite, a promising carrier for loading P. The GO-Fe carriers loaded wit...
Article
Total organic carbon (TOC) contents in agricultural soil are presently receiving increased attention, not only because of their relationship to soil fertility, but also due to the sequestration of organic carbon in soil to reduce carbon dioxide emissions. In this research, the spatial patterns of TOC and its relationship with pH at the European sca...
Article
Full-text available
Measurement and reporting of concentrations of contaminants of emerging concern such as per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA), is an integral part of most investigations. Occurrence of sorption losses of PFAS analytes onto particular laboratory-ware (e.g. glass containers) has been suggested in the pub...
Article
The aim of this study was to establish partitioning coefficients (Kd) of perfluorooctanoic acid (PFOA) in a wide range of soils and determine if those values can be predicted from soil properties using multiple linear regression (MLR) and from infrared spectra of soils using partial least squares regression (PLSR). For 100 different soils, the Kd v...
Article
Full-text available
Background Increasing zinc (Zn) concentrations in crops is important for alleviation of human Zn deficiency. Arbuscular mycorrhizal fungi (AMF) contribute to plant Zn uptake, but their contribution to Zn in the edible portion of crops has not yet been investigated. This study aimed to quantify the mycorrhizal pathway of Zn uptake into grain of whea...
Article
This study investigated the effect of surface charge on the sorption of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS) onto 7 tropical soils as a function of pH. The net surface charge became less negative with decreasing pH (from 7.5 to 3.5) in all soils. The rate of change in net surf...
Article
High profile reports of detrimental scientific practices leading to retractions in the scientific literature contribute to lack of trust in scientific experts. While the bulk of these have been in the literature of other disciplines, environmental toxicology and chemistry are not free from problems. While we believe that egregious misconduct such a...
Article
Full-text available
Methods to determine nutrient release rates of coated fertilizers usually rely on chemical analyses, which often are time-consuming and/or expensive. Our goal was to develop an innovative and rapid low-cost method to evaluate nutrient release from polymer coated MAP or urea using conductometry. The release in water is determined by measuring the el...
Patent
Fertilizer granules containing elemental sulfur and a hydrogel which expands or swells in the soil to more readily disperse the elemental sulfur surface throughout the soil, which increases the elemental sulfur surface area available for oxidation, and ultimately uptake of sulfur by the plant. The elemental sulfur and hydrogel can be added to a fer...
Article
Full-text available
Boron (B) supply to crops is a challenging fertilization practice, due to its high mobility in soil, its narrow window between deficiency and toxicity and the necessity to evenly apply this micronutrient to the soil. We aimed to increase B fertilizer efficacy through the use of slow- and fast-release borate compounds in a macronutrient carrier fert...
Patent
A granular fertilizer product having at least two sources of boron having different solubilities to tailor boron availability during the entire growing season of a plant, while reducing the risk of boron toxicity. A first source of boron can include a sodium-based or highly water soluble boron compound such as sodium tetraborate and/or boric acid,...
Article
Full-text available
AimPotato cultivars vary in biomass production and Cd concentration. Differences in growth can lead to differences in tuber cadmium (Cd) concentration through growth dilution and/or limited uptake of Cd from the soil. The aims of this study were to investigate the relative importance of shoot (above ground plant parts) and root in dry weight (DW) a...
Article
Full-text available
Soil-borne colloids have been linked to long-distance transport of radionuclides, metal(loid)s and nutrients. Colloid-associated nitrogen (N) will have different mechanisms of biogeochemical cycling and potential for water-borne transport over longer distances compared to dissolved N. The role that colloids play in the supply and mobility of N with...