Agricultural Expansion In Amazon Will Only Decrease Productivity
May 10, 2013

Agricultural Expansion In Amazon Will Only Decrease Productivity

Lawrence LeBlond for - Your Universe Online

Widespread agricultural expansion in Brazil destroys equally as much rainforest, negating any benefits for the region. In fact, researchers, publishing a paper in the journal Environmental Research Letters, have called the practice a “no-win situation.”

The research, led by Dr Leydimere Oliveira of the Federal University of Minas Gerais (UFMG), shows that deforestation will not only reduce the capacity of the Amazon´s natural carbon sink, but will also lead to climatic shifts that will decrease productivity of the region´s pastures and soybeans.

Oliveira and colleagues used two models to assess how agricultural yield would be affected in the Amazon. The first scenario was a “business-as-usual” simulation based on recent deforestation trends where new protected areas have not been developed. The second scenario was a governance simulation which assumes environmental legislation is implemented for the region.

Under the governance scenario, the model predicted pasture productivity would be reduced by 30 percent by 2050 due to a decrease in precipitation caused by deforestation. In the other scenario, pasture productivity would be reduced by 34 percent.

Also, a temperature increase could lead to a reduction of soybean yields by 24 percent in the governance model and 28 percent in the business-as-usual model.

"The more agriculture expands in the Amazon, the less productive it will become “¦ In this situation, we all lose," wrote the study authors.

Furthermore, the researchers calculated that biomass on the ground could decline by up to 65 percent between 2041 and 2060 due to a combination of forest removal and climate change.

Brazil is facing major challenges in its efforts to convert forest to croplands and pasturelands in the Amazon. The researchers explain that a fine balance must be met to work for agriculture and the climate. With less rainforest, natural ecosystems will not be able to sustain food production, maintain water resources, regulate climate and air quality, and thwart of infectious diseases.

"We were initially interested in quantifying the environmental services provided by the Amazon and their replacement by agricultural output,” said Dr. Oliveira. "We expected to see some kind of compensation or off put, but it was a surprise to us that high levels of deforestation could be a no-win scenario — the loss of environmental services provided by the deforestation may not be offset by an increase in agriculture production."

"We now have a very strong economic argument (against deforestation of the Amazon), in addition to the environmental ones," study coauthor Marcos Heil Costa at Federal University of Vicosa (UFV) told The Guardian´s Jonathan Watts. He said the study´s findings would be presented to the Brazilian government.

The researchers, who also include those from Federal University of Pampa and Woods Hole Research Center (WHRC) in Massachusetts, explained in their paper that the effects of deforestation will be felt most in the eastern Pará and northern Maranhão regions.

In these regions the local precipitation depends strongly on forest cover, and land conversion could drastically affect the local climate and lead to unviability of the land for any and all agricultural practices, they wrote.

"These simulations strongly suggest that the act of deforestation, which is being done to increase agricultural production, may perversely lead to changes in climate that reduce crop and pasture yields" noted Dr. Michael T. Coe, senior scientist at WHRC and co-author of the study. "In some cases these decreases in yield may be large enough to make agriculture economically unattractive."

"The consequences for global food security are, at first thought, worrisome. However, many scientists, including myself, believe it is possible to increase agriculture productivity in the Amazon (and in Brazil in general) through increases in productivity, without increasing planted area or additional deforestation," Costa said in his interview with Watts. "Demonstrating how this can be done and actually implementing it is the biggest challenge of agricultural science in Brazil for the next 40 years."