Home | 2006 Annual Report

Evaluation of Perennial Herbaceous Biomass Energy Crops in North Dakota

Paul E. Nyren, Ezra Aberle, Gordon Bradbery, Eric Ericksmoen, Mark Halverson, Kristine Nichols, and Bob Patton

Highlights

This 10-year study was initiated to:

• Evaluate the agronomic practices necessary to maximize the production of various grass and legume crops for biomass production.
• Determine the effect of perennial biomass energy crops on carbon sequestering and other soil physical properties.                              
• Provide an economic analysis of the production costs.

Table of Contents

Introduction

Methods

Results

Sites

Hettinger REC

Williston REC

Carrington REC

North Central REC–Minot

Central Grasslands REC–Streeter

Introduction

A dedicated bioenergy crop study has been initiated by the North Dakota Natural Resources Trust, NDSU Agricultural Experiment Station, USDA-ARS Northern Great Plains Research Laboratory, ND Game and Fish Department, ND Department of Commerce, ND Farmers Union, Jamestown/Stutsman Development Corporation, Dakota West RC&D, Dakota Prairie RC&D and Natural Resources Conservation Service (NRCS). The project will determine the appropriate grass and legume species, harvest methods, and practices to maintain productive perennial biomass stands. The costs for producing a bioenergy crop and the impact of this crop production on soil organic matter and carbon storage will be evaluated.

At the turn of the century, with the exception of trains and water transportation, draft animals like horses and mules, fed by herbaceous biomass such as grasses and legumes, powered the transportation and agriculture industries of the U.S. Since the advent of the internal combustion engine, the source of our energy has changed, resulting in our dependence on oil, both domestic and foreign. Currently ethanol is produced from small grains, primarily corn and barley, and biodiesel is produced from soybeans. This results in grain resources moving away from feed and food production and into the energy sector. Some feel that because a perennial grass used for biomass production, i.e., switchgrass, has a lower value in the feed and food market, there is little or no competition for its final use. Additionally, because the areas in which it can be grown are much more diverse, a dedicated energy crop like switchgrass offers a wider geographical impact than corn or soybeans, and a perennial production system.

North Dakota has over seven million acres of highly erodible and saline crop land, with some counties in the western part of the state having as much as 90 percent of the crop land classified as highly erodible. Perennial energy crops would achieve more long-term sustainability on this land by reducing erosion, adding organic matter, reducing greenhouse gases, and sequestering carbon. These crops also provide more economic stability for the producer and the community. Several publications have indicated that North Dakota would be a leading state in the production of biomass from herbaceous crops.

The objectives of this study are as follows:

• Determine the biomass yield and select chemical composition of perennial herbaceous crops at several locations throughout central and western North Dakota.
• Determine the optimum harvest dates for maximum biomass yield and maintenance of the stands. 
• Compare annual and biennial harvests on total biomass yield and maintenance of the stands.
• Evaluate carbon sequestration and storage of the various perennial crops.
• Evaluate the economic feasibility of the various perennial herbaceous energy crops with competing crops in the surrounding area.

Methods

The species listed in Table 1 were seeded at all locations the week of May 15, 2006 starting in Hettinger and ending with Carrington. The plots were seeded with a plot drill designed and built at the USDA-ARS lab in Mandan by Mr. Louie Zachmeier. The drill was designed to seed small-seeded grasses and legumes and is equipped to seed 10 rows on 6-inch centers. Each plot measured 15 X 30 feet and required 3 passes with the drill.

Baseline soil samples, either deep core samples to 48 inches or surface samples to 4 inches, were collected at all sites in spring 2006 by Dr. Kristine Nichols, USDA-ARS Northern Great Plains Research Lab. Deep core samples were divided into seven depths (0-2, 2-4, 4-8, 8-12, 12-24, 24-36, and 36-48 inches) and processed for gravimetric water content, soil bulk density, electrical conductivity, soil pH, total carbon (C), nitrogen (N), soil inorganic carbon, particulate organic matter, and extractable nitrate and phosphorus. Soil processing of the deep core samples has been completed, and samples have been sent to a commercial laboratory for chemical evaluation. The chemical and total C and N and inorganic C analyses will be completed by the end of 2006. Three aggregate size classes [two macroaggregate sizes (0.04-0.08 and 0.04-0.01 inches) and one microaggregate size (0.01-0.002 inches)] have been separated from surface core samples (which were divided into 0-2 and 2-4 inch depths). Water stable aggregation has been conducted on about one quarter of the samples. All surface cores will be tested for water stable aggregation and glomalin concentration by February 2007.

Results

While the summer of 2006 was dry in most of the locations, initial reports on the plots all seem encouraging. Table 2 shows the chemical and mowing treatments that were applied to the plots at each location. The plots were sprayed and mowed at least once at all locations except Hettinger, where they received only chemical applications.

Hettinger Research Extension Center

Eric Ericksmoen reported that the trial was seeded into a dry seedbed. Germination and emergence commenced with late spring rainfall. The summer was hot and very dry. Weeds, especially kochia, were abundant and competed with developing switchgrass stands. Weed control was essential in establishing treatments; however, the alfalfa and sweetclover interseeded treatments were killed by the spray. These treatments will need to be reseeded next year. Although grass stands were not tall, there was enough to visually see rows going into dormancy this fall.

Williston Research Extension Center

Gordon Bradbury reported good stand establishment in the plots, both dryland and irrigated. Weeds were a problem and the plots (except those with alfalfa) were sprayed on June 23. The weeds continued to be a problem and during the last week of July both sites were mowed. The dryland site showed signs of drought stress after a long, hot, dry stretch in July and August. The irrigated plots were mowed a second time during the first week in September.

Carrington Research Extension Center

Ezra Aberle reported that the plots were mowed three times during the summer and went into the fall having pretty good stands for the most part.

North Central Research Extension Center, Minot

Mark Halverson reported that the stand established extremely well. The switchgrass and switchgrass-big bluestem plots were the most difficult to evaluate. The 1.78" rain in July, herbicide application, and mowing probably saved the stands. The plots were mowed twice and the grass-only plots were sprayed once. The alfalfa stands looked great early on and stand establishment is expected to be nearly 100%.

Central Grasslands Research Extension Center, Streeter

The plots at the Central Grasslands also experienced stress during the growing season due to the dry conditions and high temperatures. We did experience good rains in August, which surely helped the grass stands. By first frost, the rows of nearly all the cool-season plots could be seen. The plots were sprayed

twice and mowed three times during the summer.

This study is expected to continue for 10 years. The stands will be evaluated next spring, with the first harvest expected to occur next September.