News

Soil scientists to create global soil map


13 March 2009

University of Sydney scientists are behind a technology that will map most of the ice-free land surface of the globe over the next five years in order to create something akin to a "Google Earth" for soil quality.

Professor Alex McBratney, Director of the University of Sydney's Australian Centre for Precision Agriculture, said the maps will provide information about the soil at about every 100 metres across the world. Current maps are at the scale of one to five million.

The idea is to bring soil knowledge into the digital age and to help the international battle to secure food resources, Professor McBratney says. "These maps will give us a good estimate of the production capacity for all kinds of crops all over the world, in some billions of places across the world."

Professor McBratney is working on the project, GlobalSoilMap, with a consortium of scientists in major agricultural organisations across the world. They are calling for greater recognition of the role soil plays in determining the planet's health.

With an expected world population of nine billion world population by 2050, food production needs to double, says McBratney, who is also Vice-chair of the GlobalSoilMap consortium.

The technology also has an important role to play in improving current climate change models, McBratney says. "The soil information that we produce will help global climate models by providing more detailed information about soil, which produces a lot of CO2 and sequesters a lot of carbon. The current information about soils in those areas is pretty poor."

The maps are using state-of-the-art and emerging technologies, including remotely sensed data from satellites and sophisticated geo-statistical models. These novel approaches are referred to as Digital Soil Mapping (DSM).

Using GPS receivers, field scanners, and remote sensing combined with other data, DSM processes information using computational methods such as geo-statistical interpolation, inference algorithms and Geographical Information Systems (GIS).

"We formalised the idea of predicting soil properties and classes from layers of information about the factors that control soil distribution, such as climate, vegetation, land use, position and age," McBratney says.

"This was very much helped by technologies such as remote sensing, which gave us good coverage of environmental data, and geographic information systems, which gave us tools with which to manipulate them.

McBratney says his team has developed a number of approaches depending on the amount of prior soil and environmental information available. In Australia the information will help policy makers, catchment management authorities, and ultimately farmers in agricultural planning and management.

GlobalSoilMap: some key facts- The consortium includes several major government research organisations world-wide, including the CSIRO in Australia, organizations, the US Department of Agriculture and others in Europe, Brazil, Africa and China- Despite an increasing realisation by scientists and policy makers of the crucial role soil plays in food production, the provision of clean water, the generation of greenhouse gas sinks, the provision of raw materials and the preservation of the gene pool, soil survey is a declining activity. Until now, soil survey had not changed that much over the last 50 years.- Traditionally, surveyors dug pits in the ground to examine soil characteristics. Based on this information and on their reading of the landscape, approximate boundaries between different soil types were drawn.- Digital Soil Mapping (DSM) provides soil scientists with a set of new tools to help them map soil characteristics by integrating laboratory and field data with innovative mapping techniques.- DSM can provide soil information on the Earth's surface at very high resolutions (for example, every 100 metres or, in some cases, even every 10 metres) providing information about soil properties such as texture, available water capacity, soil depth, acidity or alkalinity etc. Soil protection measures can be mapped from a limited amount of information in a rapid and detailed manner.- Through geo-statistical concepts, DSM can provide ground-breaking datasets in a way that traditional soil survey could not, and at the same time supply complete coverage of the territory under investigation.- Around 16% of the European Union's territory is affected by soil degradation. In many parts of the world, the 'sealing' of soil due to housing and infrastructure development is progressing at an alarming rate. In Germany this has been recorded at more than 100 hectares per day. Soil sealing can severely affect the natural hydrological cycle. Soil sealing contributed significantly to the recent cases of severe flooding in Europe.- In Africa, the continent most affected by low food yields, the Gates Foundation will be providing funds to help develop the maps.