Michael Lathuillière from the University of British Columbia, Canada, and colleagues from the University of Vermont, US, and Universidade Federal de Mato Grosso, Brazil, used five indicators to calculate the environmental footprint of soybean production in Mato Grosso between 2000 and 2010: deforestation, land footprint, carbon footprint, water footprint, and nutrient footprints.

Soybean production was associated with 65% of the state’s deforestation, and 14–17% of total Brazilian carbon emissions from land-use change, the researchers found. But they also noted a distinct difference in the way that resources were used in the first and second halves of the decade. Comparing the two periods, deforestation and carbon footprint declined 70% while land, water, and nutrient footprints increased almost 30%.

"This marked change coincides with the introduction of the soy moratorium in 2006; between 2006 and 2010 China surpassed Europe in soybean imports from the region," said Lathuillière. "There was a shift in soybean production system from one based on extensification [conversion of natural environment to agricultural land] to one based on intensification, for example some producers converted grassland to cropland to increase production, which also required the use of more fertilizer in an attempt to meet demand."

The moratorium excluded producers who clear rainforest for soybean production from the supply chain, the team writes in Environmental Research Letters (ERL).

Brazil is projected to be the world's leading soybean producer in 2014, rising from its number two spot in 2010. In the first ten years of the millennium the country's exports increased by 125%, with the amount going to China soaring from 16% in 2000 to 66% in 2010. Over the same timeframe the share exported to Europe dropped from 64% to 20%.

In 2010, virtual water flows were 10.3 cubic km per year to China and 4.1 cubic km per year to Europe, the researchers found. The total embedded nutrient flows were 2.12 Mtons per year to China and 2.85 Mtons per year to Europe.

"While the Mato Grosso state is blessed with abundant rainfall, most of the nutrients used to produce soybean are sourced from third party countries and imported," said Lathuillière. "This not only means that soybean production in the region is vulnerable to international markets and prices, but we also believe this extensive use of fertilizer could potentially saturate soils with phosphorous that could increase the risk of eutrophication in the long term, with subsequent impacts on aquatic life and ecosystem services."

Many policies relating to soybean import and export have opposing goals, the researchers point out. For example, environmental strategies are included in agricultural policy but not in trade policy; or countries may on the one hand support deforestation reduction but on the other demand more soybean to be produced from regions such as Mato Grosso.

"We hope our study has highlighted to producers the vulnerability of soybean production to variability in precipitation and fertilizer consumption, and how the economy is focused on soybean production at the expense of local resources," said Lathuillière. "We also wanted to highlight to consumers the hidden costs of soybean production because more resources are going to be required of the region as China’s demand for soybean increases."

Lathuillière and colleagues believe that this is the first time that a combination of environmental footprints for one particular crop has been calculated in this way. They hope to work with policymakers "to find solutions to the issue of resource use and environmental impacts".

Related links

• Environmental footprints show China and Europe's evolving resource appropriation for soybean production in Mato Grosso, Brazil, Michael J Lathuillière et al 2014 Environ. Res. Lett. 9 074001
• Michael Lathuillière, Ecohydro Lab, University of British Columbia

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