Assessment of the Environmental Impacts of Agricultural Practices in Biofuels Production Systems.

摘要

In recent years, biofuels proliferation has raised a series of questions and concerns regarding the environmental impacts and sustainability of biomass feedstock production. Understanding the complexity and nonlinearity underlying the biofuel crop production systems will allow design the production systems ensuring environmental improvement and sustainability. In an attempt to address some of the major concerns, this dissertation predicts the critical social and environmental changes caused by the large scale production of biofuels through a fundamental understanding of interconnected land use-nutrient-hydrologic systems. As demonstrated herein, farmer's cropping choice is influenced due to price incentives created by the ethanol plants and the resource constraints for animal producers to spread manure. Farmer's cropping choice can impact water quality and other environmental indicators. The cropping systems that involve more corn in a rotation and are fertilized with manure nitrogen have high potential for nitrate leaching. Corn stover harvested within limits considering the regional yield, cropping systems and fertilization practices can lower leachable N from the fields. The perennial bioenergy crops that are considered as an alternative and environment friendly for bioenergy production may not be as sustainable as being claimed upon if the agricultural hydrologic cycles are fully accounted for. The biofuel policy that encourages the expansion of energy crop production in the U.S may result in climate change and can impact soil loss, soil moisture, and streamflow. Although biofuels have potential to provide energy security, this initiative should be approached with caution to avoid adverse impacts on climate, environment and society.