Agriculture and Environment: Soybeans

Environmental Impacts of Production: Limestone Extraction

In Brazil, the lime requirements of growing soybeans in the Amazon alone could lead to considerable destruction of natural resources.

Lime (a source of calcium) is applied to soils to counteract acidity, because neutralising soil acidity makes existing nutrients more available to plants such as soybeans.

The mining of limestone requires the removal of considerable overburden (natural cover, soil, etc.) to gain access to limestone deposits. In addition, large amounts of energy are used to cook the limestone and make it into agricultural lime.

In the Brazilian savanna areas, 4 to 6 metric tons per hectare of lime are required to produce soybeans. In cleared forest areas, only 2 metric tons per hectare of lime are required, initially at least (Fearnside 2000).

This raises two issues. The first is the production and transportation of the lime itself. The second issue is the incentive to shift production into cleared forest areas that do not require the initial application of so much lime.