Location: Wheat, Sorghum and Forage Research2008 Annual Report
1a. Objectives (from AD-416)
The long-term objectives of this project are the development of improved perennial grasses and management practices and technologies for use in biomass energy production systems and grazing land in the mid-continental USA. The focus of the research will be on switchgrass for bioenergy and other warm- and cool-season grasses for grazing lands. Over the next five years, the following specific objectives will be addressed: (1) Provide appropriate plant materials for use in pasture-based livestock systems; (2) Improve the economic viability of forage-livestock systems for the Great Plains and North Central States with improved plant materials and management; (3) Provide improved plant materials for harvested biomass used for bioenergy, bioproducts, and forage; and (4) Develop sustainable production systems for harvested biomass and forage.
1b. Approach (from AD-416)
Improved perennial grass cultivars that are adapted to the Central Great Plains and Midwest states that can be used as biomass energy crops or in grazed grasslands will be developed using conventional and molecular breeding technologies. To fully utilize the genetic potential of the improved cultivars, improved management tools and practices will be developed with emphasis on improving establishment success, forage and biomass yield and quality, utilization by livestock, and all aspects of biomass energy crop production. This project is a continuation of a long-term perennial grass breeding and management program that has plant materials and management practices and tools in various stages of development. In this five-year period, focus will be on development of switchgrass cultivars for use in biomass crop production systems, developing cool- and warm-season grass cultivars for use in grazing systems, and native legume germplasm for potential future use in agriculture using conventional and molecular tools. Management research will focus on improved establishment technology for perennial grasses, enhanced methods for evaluating and renovating degraded grasslands, and improved management practices for switchgrass grown as a biomass energy crop including harvest management. Potential economic and environmental benefits of improved plant germplasm and management technologies will be determined in field and pasture trials.
3. Progress Report
Objective 1: Determined multiple biochemical pathways are involved in the dormancy and germination process of switchgrass. Results indicate that glutamate may act as a signal in the germination process. Relationships between glutamate, nitric oxide and reactive oxygen species during switchgrass seed germination are under investigation. Research on N fixation of prairie legumes are in progress using Partridge pea (an annual) and Illinois bundleflower as model species. Three new indiangrass (Sorghastrum nutans) cultivars, ‘Chief’, ‘Scout’, and ‘Warrior’ were released for use in the Great Plains and the Midwest USA in forage-livestock production systems (see the Accomplishment section). Objective 2: An indiangrass grazing study comparing ‘Scout’ and ‘Warrior’ indiangrass with the two older cultivars they were bred to replace was completed. The two new cultivars produced greater animal gains and dollars of animal product per acre than the older cultivars. Experimental bromegrass strains have been increased for use in grazing trials to be established as scheduled this autumn. A grassland assessment tool (GAT) developed by this project has been evaluated on native rangeland in Nebraska, Montana, and Wyoming. It has been evaluated on switchgrass biomass fields in NE, SD, and ND Dakota. The multi-year data has been summarized and is in preparation for publication. Objective 3. Switchgrass genotypes that differ for lignin concentration and other traits are being used to determine associated changes in plant anatomy and effects on the potential conversion of the biomass of these genotypes to ethanol. Results indicate that plant anatomy has been changed and that reduction in stem lignin concentration may improve ethanol conversion efficiency. Over 65,000 EST sequences have been deposited in public databases. Switchgrass genetics research developed switchgrass germplasm with unique genetic characteristics. The seed of these germplasm has been increased for official release. Seed of three switchgrass experimental strains are being increased for potential release as cultivars for biomass energy production fields. Objective 4. Laboratory and field validation studies of a seed quality test for determining seed lot potential for establishing stands in production fields have been completed for switchgrass and are being prepared for publication. The first year of a switchgrass bale harvest and storage study has been completed. A long-term study established in 1998 to determine C sequestration of switchgrass managed as a biomass energy crop and no-till maize managed for both grain and grain plus stover production is in progress. Data on soil carbon sequestration and biomass and grain harvests for the period 1998 to 2007 are being summarized for dissemination. Carbon sequestration results from five years of switchgrass production on ten farms in eastern NE, SD, and ND have been summarized and are very positive (see Accomplishments section). The forage and pasture research is part of National Program 205, Component II (d). The biomass engery research is part of National Program 307, Component IV.
1. Development and release of new cultivars of indiangrass, a warm-season native grass. Three new improved indiangrass (Sorghastrum nutans) cultivars, ‘Chief’, ‘Scout’, and ‘Warrior’ were released for use in the Great Plains and the Midwest USA in forage-livestock production systems. ‘Chief’ is adapted to USDA Plant Hardiness Zone 4 (HZ 4) and the upper half of HZ 5. It produces significantly greater forage yields than the other available HZ 4 cultivars. ‘Scout’ is adapted to HZ 5 in the Great Plains and Midwest, USA and potentially other regions where it has not been tested to date. It produces significantly greater forage yields than other adapted indiangrass cultivars when grown for hay in the western part of its adaptation region. ‘Warrior” is adapted to HZ 5 and the upper part of HZ 6 in the Great Plains and Midwest. It produces forage with high in vitro dry matter digestibility (IVDMD) that results in improved animal gains when utilized by beef cattle in well managed grazing systems in regions where it is adapted. In the regions where they are adapted, these cultivars also could be used in mixtures with other grasses in multi-species mixture produce biomass for bioenergy. This accomplishment relates to National Program 205 Rangeland, Pasture, and Forages, Component II Plant Resources (d) Improving forages for livestock production.
2. Determined soil carbon sequestration in production fields of switchgrass grown as a biomass energy crop. Nearly all measurements of soil organic carbon (SOC) change under switchgrass have been based on small plot research. While these assessments are useful, small plot research does not take into account spatial variability within or across farmer-managed fields. The fiscal and net energy economics of switchgrass grown as a biomass energy crop on ten farms in the central and northern Great Plains for a five year period has been reported. The soil carbon sequestration that occurred on the ten farms in these trials was determined in a cooperative ARS-Lincoln, NE and ARS-Mandan, ND study by taking soil samples at the time the fields were planted and in the spring following the fifth year of production. Across sites, SOC increased significantly at 0-30 cm (P = 0.03) and 0-120 cm (P = 0.07), with accrual rates of 1.1 and 2.9 Mg C ha-1 yr-1, respectively, demonstrating the potential of switchgrass as a carbon-negative bioenergy crop within this agro-ecoregion. The amount of sequestered soil carbon on the farms in this study exceeded the levels used in previous switchgrass Life-cycle Assessments (LCAs) for greenhouse gases. Change in SOC across sites varied considerably, however, ranging from -0.6 to 4.3 Mg C ha-1 yr-1 for the 0-30 cm depth; such variation in SOC change must be taken into consideration in Life-cycle assessments of (LCAs) of bioenergy crops such as switchgrass. This accomplishment relates to National Program 307 Bioenergy and Energy Alternatives, Component IV Energy Crops.
5. Significant Activities that Support Special Target Populations