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January 5, 2015

Degraded Pastures could be converted to Sugarcane in the Amazon

The trend in recent years in Brazil has been the conversion of degraded pastures to additional row crop production instead of clearing new land for agricultural expansion. Brazilian scientists have been promoting this conversion as an environmentally sustainable way to expand agricultural production without the need for additional land clearing. Deforestation and land clearing in the Amazon Region has been determined to be a primary source of greenhouse gas emissions in Brazil and the Brazilian government has been successful in greatly reducing the practice.

With the reduction in deforestation, there are still pressures to expand agriculture production in the Amazon Region and researchers from Embrapa feel that some of these degraded pastures could be used to expand sugarcane production in the region. They have focused their research on degraded pastures that were formerly cerrado vegetation and not necessarily rainforest. These degraded pastures are characterized by low fertility, low productivity, and high rates of soil erosion.

One of the reasons why these areas have such low fertility is due to the method by which they were cleared. Many of these areas were cleared by small family farmers using indiscriminate burning. The heat of the fire and the exposure of the bare soil to the intense tropical sun raises the soil temperatures which subsequently kills the very organisms that kept the soil fertile in its native state. Without these organisms, the heavy tropical rainfall leaches out the nutrients within a few years leaving behind very infertile soil. As agricultural production declines, many of these subsistence farmers then move onto another parcel of land continuing their "slash and burn" method of agriculture.

Scientists from Brazil's National Space Research Institute (INPE) have identified 38 thousand square kilometers (9,386,000 acres) of degraded pastures in the Amazon Region that could be suitable for conversion to more sustainable agriculture including sugarcane production.

Currently sugarcane production is prohibited in most of the Amazon Region, but legislation has been introduced in the Brazilian Congress allowing sustainable sugarcane production in these areas of degraded pastures. Scientists believe that sugarcane production could actually be beneficial for soils in the region as well as a way of improving the local economy.

Once sugarcane is planted, it can be harvested for 5-6 years keeping the soil covered for the entire time. This could stabilize the soil thus reducing erosion while at the same time allowing a return of the microorganisms needed to improve the soil fertility. The sugarcane could then be used to produce ethanol, a renewable fuel used by the residents of the region.

In addition to sugarcane, scientists feel a tree crop such as palm oil could also be a good way to utilize these degraded areas. Palm oil is a vegetable oil used for human consumption and as a renewable fuel.