ProfessorAlex McBratney

Project Opportunities

Title: Improving the auditability of soil carbon

Summary of opportunity:

Soil systems are recognised as a significant terrestrial sink of carbon. The reliable assessment and monitoring of soil carbon stocks is of key importance for soil conservation and in mitigation strategies for increased atmospheric carbon. However currently there is no reliable and efficient scheme for monitoring and accounting for soil carbon storage. This proposal will develop a methodology for auditing the soil carbon at a farm scale using a combination of spatial probability sampling and improved measurement techniques. This will enable Australian farmers to be involved in the carbon economy and will expedite sustainable soil management practices.

Opportunity synopsis:

One of the biggest problems of assigning carbon credits in soil is the expense of verification as we are dealing with the inherent variability of soil in the landscape. The amount of carbon stored in the soil per unit of land area is highly variable and depends on annual inputs, soil type and the degradation rate of the soil C. Current methods for measuring, mapping, and quantifying soil carbon within an area are expensive and inefficient. Furthermore, it is still not established how we can monitor changes in soil carbon efficiently and effectively with sufficient statistical confidence. A scheme that recognizes the whole farm as a system that can store carbon is crucial to the agricultural industry, particularly in the carbon economy.
The primary aim of this project is to develop methods for vastly improving the auditability of soil carbon, by specifically:

• Designing a protocol for auditing soil C sequestration.

• Designing an effective sampling system for monitoring the content and changes of C in the soil within farms.

• Investigating various methods for cost-effective analysis of soil C content, and possibly devising a new carbon measurement method.

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Project Opportunities

Title: How does carbon affect soil structure?

Summary of opportunity:

Soil structure plays an important role in maintaining the quality of soil, mediating important biological, chemical and physical soil processes. Soil structure determines water retention, and infiltration, hence water availability to plants, it also has the potential to sequester carbon.
Although it has been well known that soil organic carbon interacts and influences the formation of soil structure, there is little evidence of attempts being made to directly describe this relationship using mechanistic models. This project will build and validate a mechanistic model of soil carbon dynamics.

Opportunity synopsis:

We have developed a mechanistic model, named Struc-C, that describes how the soil organic carbon (SOC) influences the dynamics of soil structure, and consequently, soil physical behaviour. This model attemptsto build a connection between the biology, the chemistry, and the physics of soil aggregation. However improvements to, and validation of, the model are required. This project will seek to improve the model and investigate important parameters affecting the dynamics of soil carbon and structure. This includes the different mean residence tims of soil aggregate carbon fractions, and the relationship between organic matter input quantity and quality to SOC dynamics. Furthermore, we need to consider other factors that could influence soil structure, e.g., iron oxide sorption or the type of clay minerals.
Quantifying the components of soil aggregates and carbon and validating the model is an essential part.

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Project Opportunities

Title: Digital Terroirs for the Hunter Wine Country Private Irrigation District

Summary of opportunity:

Terroir is a commonly used concept in France and other European countries for the designation of quality wines. This concept has not been widely developed or accepted in Australia. The work will attempt to define terroirs numerically for the lower Hunter valley, based on soil, geological and terrain data as well as information on grape and wine quality.

Opportunity synopsis:

The concept of terroir is at the base of the French wine Appellation d'origine contrôlée (AOC) system that has been the model for appellation and wine laws across the globe. At its core is the assumption that the land from which the grapes are grown imparts a unique quality that is specific to that location.
This concept has not been widely developed or adopted in the Australian wine industry. The lower Hunter valley is small wine-growing area some two hours north of Sydney which produces prime wines and therefore the concept of terroir may attractive as a value-adding proposition.
A database of more than 1000 soil profiles comprising soil data and NIR/MIR soil spectra have already been collected for the area. Additionally there is a spatial information system comprising landuse and terrain data. The project would seek to gather data on grape yield and quality and wine quality using standard criteria as well as NIR/MIR spectra. These two data sets will be fused to produce initial digital terroir definitions and a map for the area comprising the Hunter Wine Country Private Irrigation District.

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Project Opportunities

Title: Conjoint use of NIR and XRF spectroscopy in the field

Summary of opportunity:

Proximal soil sensing techniques are an efficient and effective way to gather information about the soil in the field. They are used to identify and map the areal variations of soil properties across the landscape and therefore to make inferences about the quality of the soils.

Opportunity synopsis:

While we can collect detailed soil information at limited locations and interpolate the values across space and time, in some instances it would be more beneficial if we can directly measure soil information at a fine spatial scale (e.g. measurement every 10 metres). Proximal soil sensing acquires information about soil through the use of sensors that are placed in proximity to the soil in situ, which is in contrast to remote sensing.   This project will investigate proximal soil sensors for rapid measurement of soil properties in the field, particularly the conjoint use of a portable XRF (X Ray Fluorescence), and Near Infrared Spectroscopy. These instruments offer us a growing range of soil data, thus they need to be integrated using a data fusion approach.  This will be investigated with a firm ground in statistical theory, and at the same time exploiting the power of the computer to search for structure in these large data sets. 

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Project Opportunities

Title: Proximal soil sensing for improved delineation of contaminated sites

Summary of opportunity:

There are many thousands of contaminated soil sites across urban and rural Australia. These sites contaminated with metals and/or organics pose a potential threat to human health. Detection and remediation of such sites are expensive. Through a novel proximal soil sensing method combined with data –fused soil inference and optimised sampling and mapping, it is possible to efficiently identify those areas of any site requiring remediation. This will reduce the barrier to detection and remediation considerably hastening the removal of this health risk.

Opportunity synopsis:

While we can collect detailed soil information at limited locations and interpolate the values across space and time, in some instances it would be more beneficial if we can directly measure soil information at a fine spatial scale (e.g. measurement every 10 metres). Proximal soil sensing acquires information about soil through the use of sensors that are placed in proximity to the soil in situ, in contrast to remote sensing. This work will investigate the use of proximal soil sensing in soil contamination assessment. Main objectives are the firstly the development of a soil inference system with associated measurement technology that can estimate a range of possible contaminants at any location. The aim will be to generate spatial soil information with a resolution that is required for remediation of contaminated sites.

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Project Opportunities

Title: Soil in relation to sustainable viticulture in the lower Hunter wine-growing area

Summary of opportunity:

The lower Hunter valley, centred on Pokolbin, is Australia’s oldest continuous wine-growing area. It produces wines of high distinction and quality. The University of Sydney Faculty of Agriculture and Environment have mapped and monitored soil since the installation of an irrigation scheme (Hunter Wine Country Private Irrigation District) in 2000. This has resulted in the best collection of institutional, non-proprietary soil data for any wine-growing district in Australia. These legacy data along with anticipated new field and laboratory research will allow us to provide better insights into soil - wine relationships with a view to producing a viticulturally focused soil/ terrain spatial information system which will provide a basis for decisions in grape growing, winemaking and marketing.

Opportunity synopsis:

Aims 
The project will aim to

1. Refine existing maps of terrons (digital terroir) which are useful for management and in wine marketing. 
2. Develop detailed soil and land suitability criteria for particular wine cultivars, e.g., Semillon and Shiraz.
3. Ascertain the sustainability of production by assessing the soil condition through mapping stocks and rates of change of soil carbon, salinity and erosion.

Field and laboratory work 
This work will involve further detailed and targeted soil sampling to improve our understanding of stratigraphy and parent materials and to investigate land use effects. The use of geophysical survey procedures of electromagnetic induction and gamma radiometry will be required as well as field and laboratory infrared and X-ray fluorescence spectroscopy.

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Project Opportunities

Title: Securing Soils for the Future: Advancing the Soil Security Framework

Summary of opportunity:

Soils underpin food, water regulation, climate mitigation and biodiversity, yet their long-term security is not guaranteed. This project advances the soil security framework by integrating its five dimensions - condition, capability, capital, codification and connectivity - to develop practical, scalable pathways for securing soils from farm to national and global levels. Depending on interest, candidates may quantify soil condition (e.g. carbon, structure, water), assess capability under changing climates and land uses, value soils as natural capital for reporting and policy, contribute to digital codification (including the emerging global pedogenon), and design connectivity mechanisms that link science to governance and on-ground adoption. The aim is to generate evidence and tools that decision-makers, land managers and institutions can use to safeguard soils for the mid-21st century and beyond.

Soil security provides a conceptual and practical framework to ensure soils continue to sustain humanity and the planet. It recognises that protecting soils requires an integrated approach across biophysical, economic and social domains.

This project will enable candidates to explore one or more dimensions of soil security:

Condition - Quantifying soil attributes such as carbon, structure and water under climate and land-use pressures; developing indicators and uncertainty frameworks.

Capability - Evaluating soils' capacity to support agriculture, ecosystems and communities into the future; scenario analysis for adaptation.

Capital - Measuring soil as natural capital and linking it to ecosystem services, sustainability reporting and investment.

Codification - Contributing to consistent soil information systems (e.g., the global pedogenon), digital mapping and data interoperability.

Connectivity - Investigating governance, policy and community engagement required to embed soils in decision-making and accelerate adoption.

Methods may include field sampling and laboratory analysis, geospatial modelling, spectroscopy, data science, systems and policy analysis—tailored to the candidate's background. Outcomes will inform soil stewardship from farm to global levels and position soil security alongside climate and biodiversity in sustainability agendas.

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Project Opportunities

Title: Connectivity and Governance for Soil Security

Summary of opportunity:

Securing soils is as much a societal and institutional challenge as it is a biophysical one. This project investigates how connectivity - between farmers, advisors, policymakers, and global institutions - can underpin effective governance frameworks that protect and enhance soil condition.

The soil security framework emphasises that soil condition must be understood in relation to governance, codification, and connectivity. Achieving global soil security requires pathways that connect people, institutions, and knowledge systems with soils themselves.

This project will explore:

Policy frameworks at national and international levels that influence soil stewardship.

Connectivity mechanisms - extension networks, supply chains, digital platforms - that affect uptake of practices improving soil condition.

The economics of soil security, including cost-benefit analyses of improving condition and natural capital accounting.

The feasibility of an international"soil accord” as a unifying mechanism for soil governance alongside biodiversity and climate agreements.

Students will have scope to use interdisciplinary methods - policy analysis, systems modelling, and stakeholder engagement - to propose globally relevant pathways for securing soils.

----------Current Research Projects----------

 Alex is passionate about the sustainable use and management of the soil system. He is trying to unravel the causes of soil change in space and time and is intrigued by questions such as;

•  what makes soil tick, and
•  how where and when does soil grow?
•  how do we secure soil for sustainable development?

 He seeks to develop answers to such questions through the combination of observations and quantitative theory. The understanding that provides answers to such questions helps us to create sustainable ecosystems and provide food, water and energy for humanity more securely.