Course: BFM 101 Biofuels Fundamentals

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Bioenergy Crop Production: Best Management Practic…
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Landscape Diversity
Landscape Diversity

Historically, farms in the United States have been multiple agricultural enterprises (diverse systems) with pastures, multiple annual and perennial crops and more than one species of livestock. Diversified farms generally maintained smaller crop fields and pastures, which created a landscape more closely resembling wild lands. Economic pressures, federal policies and lifestyle choices have encouraged a less diverse agricultural system and, over time, farms have evolved into much more focused annual crop and confinement livestock farming systems. In the upper Midwest, corn ands soybeans are the two main annual agricultural crops grown in rotation. Some people consider this to be a monoculture system.

Farmland that contains a mix of annual crop and perennial habitats will support more species and more ecosystem services than farmland dominated by one or a few annual crops. In many areas, annual crops are produced on marginal land. Planting these areas with perennial biofuel crops could increase landscape diversity, which is important because different organisms may have different needs. Perennial biomass crops provide beneficial ecosystem services like erosion control, reduced pesticide use, and reduced fertilizer use. Such diverse landscapes may support more types of organisms, ensuring that a decline in one species is offset by the presence of another to fill a need. In addition, species may meet their various needs by using different habitats; diverse landscapes could provide for these needs.

Scientific evidence can be used to derive some general predictions about how different biofuel crops and landscapes could impact ecosystem services. Below we provide some general findings that could be used in the design of biofuel landscapes.

Fact Sheets
Biodiversity Services and Bioenergy Landscapes

Habitat Stability and Perenniality

Frequent soil disturbances, removal of vegetation and use of pesticides disrupt ecological processes and ecological communities, reducing delivery of critical ecosystem services. In contrast, habitats with perennial vegetation and more stable conditions can support increased biodiversity and ecosystem services. Stability and perenniality could be included in biofuel landscapes in two ways. First, annual biofuel crops can be grown using reduced-tillage and cover crops, which will reduce soil disturbance and provide a continuous cover of vegetation. Second, biofuels could be produced from perennials, such as switchgrass, mixed prairie, or fast-growing woody species. These habitats are more stable than those provided by annual crops because the vegetation persists for multiple years.

Diversity of Plant Species

Habitats with multiple plant species may support greater biodiversity and ecosystem services than habitats dominated by a single plant species. Plant diversity could be incorporated into biofuel production systems through the use of crop rotations and cover crops. Alternatively, biofuels could be produced from diverse grasslands (e.g., mixed prairie) that contain a variety of plant species.

Strategic Design

The ecological benefits of a given cropping system depend on the situation. Biofuel production landscapes should be designed and established to produce the most value. For example, strips of grassland and forest can be planted to intercept runoff from crops. All else being equal, these strips will provide the greatest benefits for water quality when they are planted along streams (and provide less benefit when located far away from them). Similarly, connecting existing natural areas with strips of perennial habitat may increase the movement of pollinators, predators, and wildlife across the landscape by providing corridors. In contrast, planting an isolated patch of natural area may do little good if organisms from existing natural areas cannot reach it.

Bioenergy Production for Multiple Services

Biofuel crop systems can provide diverse landscapes that produce food and fuel and enhance crop pollination and natural pest control while supporting a variety of other services that have value beyond crop yields and net returns. In short, biofuel production provides a chance to do agriculture in a fundamentally different way. These are just a few examples of how bioenergy crops can be used to create multi-functional landscapes:

- Buffers of fast-growing trees and perennial grasslands could be planted along waterways. These buffers could reduce runoff into streams, increase water quality (improving fish habitat), and provide corridors that allow wildlife to move between patches of forest.
- Rows of bioenergy crop trees could be planted in open areas to reduce wind erosion and provide habitat for predators of crop pests.
- Conventional tillage could be replaced with no-till systems and cover crops could be used more extensively, which would support predatory insects and spiders that control pests, reduce erosion, and improve soil quality.
- Suboptimal farmland (e.g., center pivot corners or marginal soils) could be planted with perennial grasslands to increase soil organic matter and provide habitat for bees, birds, and predatory insects.

Resources provided by the eXtension Farm Energy Community of Practice at http://www.extension.org/ag+energy

Bioenergy Crop Production: Best Management Practic…
Carbon Offset Markets