Changes in Erosion and Runoff due to Replacement of Pasture Land with Sugarcane Crops

The planting of sugarcane crops has expanded in the last decade in the southeast of Brazil, mainly due to its use for biofuel production, such as ethanol. This expansion in the State of Sao Paulo has occupied land that was previously used for cattle production. The change in land use affects soil and water through changes in ground cover and disturbance associated with farming practices. The objective of the following study was to determine the impact on runoff and erosion resulting from the conversion of pastureland to sugarcane for biofuel production. Erosion plots measuring 100 m(2) were built on a farm in Itirapina-SP, Brazil, on land with a slope gradient of 9% and soil composed of Quartz-sand Neosols (Typic quartzipsaments). The treatments were an 18-year old pasture and a new sugarcane plantation, with three replicates for each. After each rainfall episode, erosion and runoff were monitored during the first and second years after sugarcane was planted. The results show increased runoff and soil loss during the first year, though levels decreased in the second year when the sugarcane residue mulch ground cover increased. In addition, the necessary rainfall characteristics (e.g., intensity, duration) required to produce runoff and soil erosion were identified.