Giant Miscanthus Grass - good or bad?

With all the talk of biomass production, I thought this might be of interest to farmers.

Miscanthus (Miscanthus x giganteus) hybrid grass is being promoted by several universities and other organizations as a solution to some of our energy needs. Reading articles and watching videos on miscanthus would lead people think it is the best new idea around with no problems. Miscanthus has been evaluated and widely planted in Europe during the past 5-10 years as a bioenergy crop. In spite of perceived positive attributes, there may be negative considerations to planting this crop. More Missouri research is needed to answer these questions.

Some promoted advantages are:

Miscanthus

- Miscanthus is a large perennial grass with a great potential for use in alternative energy production for fuel and cellulosic alcohol production.

- Giant miscanthus is widely grown in Europe as a bioenergy crop.

- Fields planted to non-invasive miscanthus can be easily reclaimed for corn/soy bean.

- Miscanthus grass is being promoted as a high yielding, low/no input crop. Mineral nutrients translocate into the plant’s crown in the fall and will continue even after frost.

- Excellent for carbon sequestration and soil building.

- NRCS cost share is available through the Biomass Crop Assistance Program (BCAP) for field establishments.

- Yield estimates are from 10 to 15 tons per acre.

- There is potential for income generation through carbon credits.

- Miscanthus begins growing at lower spring temperatures and stops growing later in the season than other warm season grasses.

Some of the not so commonly mentioned disadvantages or questions are:

- Miscanthus is a large, tall, dense growing perennial grass with few wildlife friendly uses.

- As a hybrid, the seed is not viable but the plant may be invasive through rhizome spread.

- There are concerns that miscanthus may produce an extremely small percent of viable seeds but due to the high density plantings, a few viable seeds may be enough to cause invasive spread.

- More Missouri research is needed on yields, fertilizer needs and ideal soil fertility levels.

- More Missouri research is needed on applying for carbon credits, carbon sequestration and soil improvement.

Pressed Miscanthus core



- Many Missouri fields are poor choices for miscanthus plantings because of erosion potential. Cost share is available from BCAP if the fields do not exceed soil loss requirements. Unfortunately, seed beds should be of loose, tilled soil 4 to 6 inches deep making them highly prone to erosion.

- Miscanthus yields are strongly influenced by water availability of at least 30 inches of rainfall a year.

- MU Agricultural Economists have not completed economic evaluations.

- MU Agronomists have not completed assessments on how miscanthus fits in to Missouri management and agronomic practices.

- There are few alternative uses such as for forage.

- Miscanthus is an exotic plant grown in a monoculture.

- Expensive to plant. Rhizomes are used for establishment plantings. The recommended planting depth is 4 inches.

- Miscanthus has been shown to serve as a host for corn rootworm and other insect pests of commercial crops. What effect this has on pest dynamics in near-by crops is unknown.

- Typical forage harvesting equipment on farms may not be compatible or efficient for miscanthus bioenergy harvesting.

Miscanthus rhizomes

There are a number of giant miscanthus grass plantings planned this spring in central Missouri. More will be learned about miscanthus, bioenergy crop establishment and production through these and other plantings.

Dr. Emily A. Heaton, Assistant Professor of Agronomy at Iowa State University, has stated that the ideal dedicated biomass crop is a perennial that efficiently uses available resources, stores carbon in the soil, is an efficient user of water, has low fertilizer requirements and is not invasive. Giant miscanthus (Miscanthus x giganteus) possesses many, if not all, of these characteristics.

By Jim Jarman, MU Extension Agronomy Specialist. Information came from the University of Missouri and other land grant universities, USDA, NRCS’s Technical Note No. 4, “Planting and Managing Giant Miscanthus as a Bioenergy Crop”, and videos from the US and Europe.