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July 7, 2010 Volume 31, No. 33

Mizzou ‘Flood Lab’ research paves the way for renewable crops of cottonwood biomass

Flood lab

Mizzou scientists are studying the feasibility of growing biomass crops on flood-prone farmland that no longer can be used for more traditional crops. That research is taking place at a unique “flood laboratory” at MU’s Horticulture and Agroforestry Research Center at New Franklin, Mo. Researchers can floodcontrolled swaths of the lab to find ideal flood tolerant trees, such as cottonwood. Horticulture and Agroforestry Research Center photo

Practical solution

New Franklin site first scientific test of flood tolerance

The Missouri River floods of 1993 and 1995 devastated thousands of acres of rich farmland with inches of sandy silt left behind after the water receded.  Even if the sand could be removed to restore the soil to productivity, one heavy rainy season could ruin everything again.

Research at the flood laboratory at MU’s Horticulture and Agroforestry Research Center (HARC), at New Franklin, Mo., has found a practical solution to make such bottomlands economically productive again — cottonwood trees.

Cottonwoods are among the fastest growing trees in North America and mature in as little as two years. They can be sold for biomass, rough-cut lumber for home framing and high-quality lumber for cabinets. Their short and fine cellulose fibers also make them an excellent paper source. Extracts from their fragrant buds are used in perfumes and cosmetics.

A renewable resource just like traditional crops, some varities of these trees thrive in boggy and sandy areas that can no longer sustain traditional crops.

The cottonwood research took place at a unique laboratory, one recognized as the most realistic flood simulator in the Midwest and possibly in America.

The flood lab at New Franklin, a part of the MU Center for Agroforestry, features a dozen two-foot-deep flood channels that can be individually flooded and drained to simulate a variety of flood conditions.

Built near the banks of Sulfur Creek, the laboratory’s channels, each approximately 20-ft. wide by 300-ft. long, can be independently adjusted for water depth, standing or flowing water, and duration of flooding. Selected grasses, legumes and tree species are planted in the channels to determine their flood tolerance abilities.

Experiments at the flood lab also tested the survival and recovery rates of certain hardwood trees to floods, and what genetic changes to trees can make them more flood tolerant.

One test, completed late last year, confirmed that certain cottonwoods could withstand potential Missouri floods and be an economically viable crop that could be grown in flood prone areas.

The flood lab came from a brainstorming session after the ‘93 flood, recalled former MU agronomy Professor Bob McGraw. He and his colleagues envisioned an outdoor laboratory where researchers could screen Missouri plants for flood tolerance and offer farmers substitutes for traditional crops in almost useless bottomlands.

There was no such large-scale simulator available. The closest equivalent was a tub filled with soil in a greenhouse. That could work for individual plants and grasses, but a tub can’t handle trees. Also, greenhouses don’t replicate real field conditions.

The research center at New Franklin was a natural place for such a lab. The 660-acre farm hosts agroforestry research programs, experimental fruit and nut orchards, and forage shade tree trials. The farm is also the location of one of Missouri’s oldest brick homes, the 1819 Thomas Hickman House.

It is one of 17 research farms of the Missouri Agricultural Experiment Station, a network of sites across the state where state-of-the-art research and demonstration programs bring Missouri land owners new information for reaching maximum income potential in each of the state’s major soil and climate regions.

These facilities provide researchers and extension state specialists more than 14,000 acres of land and equipment for field experiments and demonstrations and provide information for industry and state and federal agencies.

H.E. “Gene” Garrett, forestry professor and former director of the Center for Agroforestry, came upon the idea of flood tolerant cottonwood trees as crops during a walk along a river bank during the ‘93 flood.

Some species of cottonwoods, he noticed, were thriving in the floodwaters while other trees had perished. Garrett and John Dwyer and Hank Stelzer, both associate forestry professors, used the new flood lab to test different genetic selections of cottonwoods to learn which are best suited to flood-prone areas.

Garrett pointed out that before the MU flood lab there was little scientific evidence on which trees were flood tolerant.

He and his team built the flood lab so that plants can be tested in flood conditions adjacent to identical control plants that receive the same sunlight and grow in the same soil conditions.

Data on tree flood tolerance, plus known information about commercial markets for cottonwoods, are being been distributed via seminars, brochures and other methods to Missouri farmers who now have one more option for bottomland sites prone to flooding.