As a result of the production of sugarcane for bioethanol in Brazil, certain individuals and organisations have raised the issue of the damage that is being done to the soil quality in the areas of production. According to these studies, numerous negative aspects have resulted in the soil due to the shift to sugarcane production.
Firstly, the natural levels of organic carbon typically found in the soil has been decreasing. The scientific community believe that this is due to the preparation practises associated with bioethanol. During the period when the ground is prepared for the shift in land use and additionally while sowing the seedlings, extensive areas of bare soil are left exposed to the elements leading to the loss. The carbon found in soil (primarily in the form of organic content such as decaying leaves) is the largest carbon sink in the world and therefore the reduction of it could have dramatic consequences.
Secondly, the biological activity within the soil has decreased. This process includes the breaking down of organic matter within the soil by organisms such as worms. This reduction in activity is due to the fact that the fields are continually in use, never left fallow to rejuvenate, and that heavy industrial machinery are employed at every stage of cultivation.
Thirdly, and lastly, the process of production is also thought by some to lead to soil compaction, specifically due to the weight of the machinery involved. If true, this would have a negative impact of the physical properties of the soil by increasing its density and, in turn, decreasing the permeability of the soil to water molecules, increasing the quantity of run-off water that is not absorbed.
The primary individuals involved in raising awareness of the impact that sugarcane production has on the soil are Luiz A Martinelli and Solange Filoso in their article, Expansion of Sugarcane Ethanol Production in Brazil: Environmental and Social Challenges (Ecological Applications, 18 (4) 2008, pg 885-898). Their article has been cited in 64 additional articles on the subject.
However, businesses in the bioethanol industry dispute their findings since they believe that the data produced is exaggerated.