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Energy grass test begins near Manning

By Staff | Jun 3, 2011

Randy Kasparbauer sits behind one of the two planting tubes on the old two-row corn planter he converted to plant rhizomes for giant miscanthus grass near Manning.

Denny Kasparbauer, and his son Randy, of rural Manning, are investing one acre of land between two terraces to experiment growing giant miscanthus grass.

They want to learn if this 10-foot tall Asian grass can be grown in west central Iowa soils and climate and how it will yield. They are starting an experiment that will last two years and possibly much longer.

Giant miscanthus grass is a huge biomass producer in many parts of the world, producing from 10 to 20 tons of dry matter per acre. This is twice as much as Iowa’s native switchgrass, which has been the leading grass biomass grass producer to date.

Miscanthus is a long term perennial but starts slowly, so it takes at least two years to reach maturity. The first year, there is no biomass harvest as the root systems are developing.

The Kasparbauer men hope to produce four tons per acre of dry grass at the end of 2012, and 10 tons at the end of 2013.

A miscanthus rhizome is planted less than 2 inches below the surface. The plot has 6-, 12- and 18-inch spacings in a row. Rows are 40 inches apart. Plants will take two years to mature.

In future years as the roots expand and become deeper; they hope to reach 20 tons per acre. Smaller Illinois test plots have reached 24 tons per acre.

This grass is a sterile hybrid that does not produce seed. It is planted by burying three-inch rhizomes in the ground at two inches deep. The grass stems are surrounded by long leaves that drop each fall.

Then the bamboo-like stalks are harvested.

The tall grass stalks can be utilized in two ways – as biomass for fuel or burned for electrical energy production, which is common in Europe; or there is the possibility of converting miscanthus grasses to ethanol by cellulosic conversion.

This process is being studied now with corn cobs at the Poet biorefinery ethanol plant near Emmetsburg.

Because giant miscanthus loses its leaves before fall harvest, that organic matter provides the protective cover plant residue for the fields to prevent erosion.

It is anticipated that this grass will be likely grown on sloping lands that need perennial grass protection and are less favorable for row crops.

The Kasparbauers have divided their one-acre test site into three 30-foot wide strips, each 500 feet long. The first strip has high plant density of 24,000 rhizomes per acre, roughly six inches apart in the 40-inch spaced rows.

The second strip has a medium density of 16,000 rhizomes planted 12 inches apart. The final strip has a low density of 8,000 rhizomes planted 18 inches apart. They will study how fast the plant sends out new rhizomes and fills in between plants and also between rows.

They planted on May 18 into a row crop field that was soybeans in 2010.

To plant the three-inch long stick-like rhizomes, they fashioned their own planter using an old two-row corn planter from the 1930s.

Even at one acre, this experiment is the largest in size in Iowa for biomass production of giant miscanthus.

Iowa State University and the Southern Iowa Resource Conservation and Development Inc. have smaller test plots of different varieties of miscanthus, but no plot is over 12-by-12-foot. There are no other test fields in northwest Iowa.

Because of its form and height, giant miscanthus can produce twice as much biomass as native switchgrass. Giant miscanthus grass has been growing for 22 years in Denmark and has not spread beyond five feet from its original planting site.

This is important to avoid non-native plants that become invasive over time. Because seeds are sterile, only movement of the rhizomes can spread the plant.

Randy Kasparbauer is a 2009 ISU graduate in mechanical engineering. He studied bioenergy methodology as an undergrad.

He also currently works with Deere & Co. in Des Moines.

Denny Kasparbauer lives on the farm and also manages a tiling business.

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