Growing and Propagating Giant Miscanthus Grass for Biomass Production and Natural Resource Conservation

Growing and Propagating Giant Miscanthus Grass for Biomass Production and Natural Resource Conservation

Summary

The grant project has started successfully and has made a good start through the first year. The initial work was completed and the grass was properly established. We await much of the results following the completion of the second year. After the first year it was determined not enough biomass was produced to justify a harvest, and that rhizomes did not multiply significantly enough to justify massive digging and replanting.

A blog was started to track the progress of the project. It can be viewed at http://growingmiscanthus.blogspot.com/.

Objectives/Performance Targets

Year 1 objectives:
* Acquire land for the plot and subplots
* Acquire miscanthus rhizomes
* Acquire planter to plant rhizomes
* Plant rhizomes
* Monitor growth
* Treat weeds
* Get expert advice
* Provide outreach

For year 2:
Due to the slow growth during the first season, the biomass will be left unchanged for the second season. The biomass analysis of the small amount of miscanthus that was harvested will be returned. This will be used as a sample to send to local companies and farmers that may be able to utilize the grass for energy.

Soil samples will be taken again in the spring before new growth begins. This will provide the first of two comparisons that will be made with the ground before the miscanthus was planted.

The weed level will be monitored closely in the first few months of growth. The large amount of foxtail grass that volunteered in the plot left a lot of seed that is now on top of the ground. Keeping any of this grass form volunteering will be important to allowing the miscanthus to grow without competition.

It is expected that the plot will have much better growth during this second year. A field day will be scheduled in the early fall if results by early summer are promising. This will be done with local USDA offices, the Iowa State University Extension, and the local community.

At the end of the second season the grass will be harvested. Regardless of the level of growth of the grass, the biomass will be harvested in order to determine second year harvestable weight. It is expected there will be enough time left in the year to also record a final soil sample to determine the total nutrient loss taken from the soil after two years.

The mass of the biomass will be evaluated. Based on the observations during the first year, the ratio of biomass coming from the miscanthus leaves versus the stalks will also be recorded during the second season. The biomass from the second year will also be evaluated for biomass content.

Accomplishments/Milestones

After receiving the grant funds, we immediately made the purchase of miscanthus rhizomes for our plot trial. The rhizomes were purchased from New Energy Farms out of Ontario, Canada. The rhizomes were dug up and shipped from a nursery plot in Georgia. The plants were received a few weeks after payment and were stored in a dark, cool room until planting was commenced.

A blog was started to track the progress of the project. It can be viewed at http://growingmiscanthus.blogspot.com/. Randy Kasparbauer does the posting and maintenance on the miscanthus blog. Useful pictures and commentary were used to track the progress of the first year.

Shortly after the grant was awarded, a planting device was needed. First we contacted New Energy Farms for contract planting. Their available equipment was much too large and designed for hundreds of acres. They assured us we would not be happy with the results we would get in our 1/3 acre plots. We opted for a Lister-style corn planter that digs a deep and wide furrow. The corn planter was purchased and modified to accommodate a chute for depositing rhizomes behind the plow shank, and a seat to allow two people to ride on the back of the planter to manually feed rhizomes into the chute.

Planting was completed on May 18, 2011. The weather was ideal and the ground was dry to slightly damp in areas. The ground planted very well with the only exception in an area of heavy clay that did not plow well. Unseasonably warm conditions provided for early planting in the area. Some corn was planted earlier in the month nearby the rhizome plot.

Rhizomes were planted approximately 4 inches deep. The rows were 40 inches apart. Each of the three 1/3 acre plots had 8 rows 500 feet long. Three areas were planted with different spacing of plants in each row. This was done manually by the two people planting the rhizomes on the back of the planter, and it was also affected by the speed of the tractor in the field.

The first plot was planted at 24,000 rhizomes per acre. It was 1/3 acre to the north edge of the plot. The second 1/3 acre plot was through the center of the full area and was planted to 16,000 rhizomes per acre. The last 1/3 acre plot was to the south of the main plot, and was planted to 8,000 rhizomes per acre. Grant funds were used for labor of 3 people to help plant.

During the day of planting, John Klein, the Carroll, Iowa USDA-NRCS Coordinator, made a visit to meet us and learn more about our grant project. He was able to take some photos and author a nice article explaining the process for all the surrounding local newspapers.

The rhizomes received adequate rain and sunlight over the growing season. One treatment of herbicide was required to kill back weed pressure on the new plants early in the season. This helped in the early stages of the grass, but late in the season the miscanthus received some pressure from foxtail grass that was unable to be removed. The foxtail matured beside the miscanthus.

In the early winter season, a patch of the grass was manually harvested by hand to be analyzed for biomass content. The overall make up of organic matter in the plot was too small to justify a harvest and no biomass was able to be mechanically harvested the first year.

In November, we were able to attend and present at the National Small Farm Tradeshow and Conference. This was a good experience to learn about other projects that are going on and to inform others about our project. There were a few very interested people and a few people doing additional research in biochar production. Making biochar out of miscanthus might be attempted with some of the biomass harvest.

Impacts and Contributions/Outcomes

Establishing the miscanthus was determined to be fairly straightforward and was deemed a success. The overall growth rates of the grass was slow so that a full stand was not available at the end of the first year. Weed pressure was not significant early in the season, but did increase throughout the growing season. For future large plots, a method of cultivation or inter-row grass removal will be needed until the miscanthus grass is able to fill in between the rows with its own growth.

A soil sample was recorded at the beginning of the season for each sub plot area of study. The soil was analyzed at the soil lab at Iowa State University. This will be a base line for soil nutrient retention.

At the end of the season, the miscanthus had grown to 6 feet tall in the best areas and had filled out as much as 8 inches wide on the base of many plants. The volume of miscanthus in the plot was less when compared to other volunteer grass. If the plot were harvested after the first year, the total mass of miscanthus would not be able to be measured. An additional year is needed before the grass can be harvested.

It was learned that digging miscanthus rhizomes is very difficult in soils with high clay content like those in western Iowa. The fact that the soil is very dense and sticky does not lead well to sieving out rhizomes from the soil. Also, the roots need to be separated from the dirt cleanly, including a water wash. To dig up rhizomes, a tool is needed to pull up the top six to nine inches of top soil and sieve out roots from the dirt. Since there is so much foreign matter in the fields and the dirt is somewhat clumpy, it was not possible to harvest rhizomes after one year of growth. The practice of harvesting rhizomes will be reevaluated in the fall of 2012 to see if a rhizome harvest is more feasible.

Some plants were dug up for initial investigation. The level of multiplication of the rhizomes was either not apparent or not easily found with digging. Also, it was determined about half of all rhizomes did not create plants above ground in the first year. The dormant rhizomes had not begun to grow the first year. We hope many will begin to grow above ground in the second year. An expert from New Energy Farms will be consulted on what steps can be taken next. The harvesting of rhizomes was postponed and a possible harvest will be reevaluated after the second season, prior to the expiration of this grant.

It was determined during the small manual harvest that was made that the miscanthus grass has significantly different components in its physical structure. The leaves make up a significant portion of volume, but the stalks make a significant portion of the mass. Also, the miscanthus stalks were much stiffer than traditional grass. Alternative harvesting methods will have to be used compared to standard bailing. The stiff and long miscanthus stalks will not bale well based on the physical composition. Alternative methods will be considered and evaluated throughout the year until a decision is made at harvest time.

Collaborators: