Location: Forage Seed and Cereal Research2010 Annual Report
1a. Objectives (from AD-416)
Objective 1. Develop economical conservation practices for grass seed production systems that effectively reduce sediment transport and maintain water quality, crop productivity, and wildlife habitat. • Sub-objective 1.1. Develop biophysical data at a watershed scale that quantify the effectiveness of selected conservation practices within grass seed production systems in reducing sediment transport and maintaining water quality. • Sub-objective 1.2. Quantify the relative contributions of grass seed fields and adjacent riparian zones to aquatic and avian wildlife habitat quality. • Sub-objective 1.3. Develop indicators of ecosystem service capacity that are geo-spatially linked to agricultural practices. • Sub-objective 1.4. Optimize the placement of conservation practices and precision agricultural inputs that account for in-field variability in seed yield. Objective 2. Provide value-added opportunities for local-scale conversion of grass straw into bioenergy. • Sub-objective 2.1. Quantify the geo-spatial distribution of straw and associated feedstock transportation costs and the impact of cost on the conversion scale suitable for the Pacific Northwest. • Sub-objective 2.2. Conduct an on-farm pilot trial to evaluate the feasibility of commercializing local-scale thermochemical conversion of straw into bioenergy within an annual farming operation cycle. • Sub-objective 2.3. Quantify the impact of straw removal from a perennial grass seed production system on carbon sequestration and soil quality. • Sub-objective 2.4. Characterize straw ash chemical composition and the potential for application as fertilizer additive and soil carbon supplementation. Objective 3. Integrate available information regarding production, conservation, and potential value-added enterprises to improve whole-farm profitability and accomplish conservation goals and requirements in support of USDA Farm Bill Conservation Title. • Sub-objective 3.1. Quantify the impact of agricultural pollution abatement strategies and policy instruments for optimal selection and placement of conservation practices to maximize farm profitability and environmental quality and enhance rural quality of life. • Sub-objective 3.2. Evaluate relative economic and environmental services trade-offs of introducing bio-based energy production into existing agricultural production systems.
1b. Approach (from AD-416)
Societal expectations that U.S. agriculture provide stable supplies of food and fiber while maintaining or enhancing natural resource quality require agricultural systems that achieve multiple objectives while maintaining profitability. Optimizing the use of production options, including new value-added opportunities in bioenergy along with Farm Bill Conservation Title incentives, while minimizing the impact of rapidly rising fuel and fertilizer costs is critical in achieving these multiple objectives. This research project will develop new information on ecosystem services provided by perennial grass seed cropping systems under contrasting management practices, evaluate the potential for converting agricultural residues produced by these systems into an on-farm value-added revenue stream, and quantify the impact of residue removal on soil and water quality. This new information will be utilized in the computer-assisted optimization routines to identify sets of management options that enable producers and policy-makers to make informed decisions that achieve societal and producer expectations of productivity, sustainability, and profitability. The information and technologies developed within agroecosystems that are unique to the Pacific Northwest (PNW) represent an integral part of the CEAP (Conservation Effects Assessment Program), REAP (Renewable Energy Assessment Program) and GRACEnet (Greenhouse Gas Reduction through Agricultural Carbon Enhancement network) projects and will be widely applicable to agroecosystems across the country that provide the focus for these national initiatives. The research addresses components of National Programs 207/216 and 307. Replaces 5358-21410-002-00D (2/09).
3. Progress Report
Significant progress was made in achieving the goals of NP216. We are developing technologies to support sustainable local-based energy production to enhance rural economic development. Kentucky bluegrass mill screenings have been utilized successfully as feedstock for the farm-scale gasification unit with continuous operation for up to eight hours. The syngas produced by gasification of these screenings has an unusually high content of carbon monoxide and methane, providing a gas with medium heating value. Tar content and particulate matter in the syngas is directly related to the rate at which screenings are fed into the reactor, increasing with feed rate. Silicon, carbon, and potassium are the primary constituents that remain in the char after the screenings are gasified. This research will enhance farm economic competitiveness. Further, an added-value product from the straw gasification process is residual ash (biochar) that could serve as a soil supplement to enhance fertility and reduce fertilizer costs. We are testing the feasibility of this. Farm economics is also directly linked to agricultural sustainability and environmental protection, through incorporation of conservation practices into farm management plans, thus we continue to make considerable progress towards understanding relationships among biotic and abiotic changes with respect to various land management scenarios and soil and water quality, as well as aquatic and terrestrial wildlife ecosystem services. In addition, research data are being integrated into biophysical models to identify optimal sets of management practices that achieve desired outcomes set by policy makers and/or land managers. The steps we are taking in our research, and the outcomes that follow, have the potential to support the analysis of many of the economic and policy questions facing U.S. Agriculture today.
1. Ash from combustion of grass straw biofeedstock used as a soil amendment. Biochar is a byproduct of on-farm gasification of post-seed harvest grass seed crop straw residues during the production of bioenergy. Utilized as a soil amendment, biochar might have added value to the farm enterprise by returning macro- and micronutrients removed with straw harvest back to the production field. ARS scientists in Corvallis, OR, determined that grass biochar contains potassium and other minerals used by plants and could be returned to the soil as a soil amendment without harming plant growth. If implemented on-farm, these amendments would be a value-added recycling of useful minerals critical for healthy crop growth and reduce fertilizer inputs.
2. The role of voles in improving soil quality. Voles are well-known crop pests, especially when peak populations are present, but their role in soil fertility and impacts on agricultural sustainability are far less understood. It could be that vole activity, although destructive at times, may have underlying benefits that are overlooked with regards to long-term agricultural sustainability and soil health. ARS scientists in Corvallis, OR, found that vole belowground burrowing activity significantly enhanced soil nitrogen, soil moisture, soil organic matter, and other important plant nutrients, such as potassium. Like the vole’s distant relatives the gophers, voles have profound effects on soil chemistry and structure that impact ecosystem services at the landscape scale that have not been considered when viewing long-term agricultural sustainability.
3. Straw distribution defines optimum biofuel conversion sites. Development of a sustainable cellulose-based biofuel industry is currently struggling with questions of which of the evolving technologies to use, what size plants to build, and how to minimize costs of straw collection and transportation. Based on remote sensing of grass seed and cereal production across the Pacific Northwest, ARS scientists in Corvallis, OR identified optimal locations for hypothetical plants operating at three contrasting scales using an iterative siting process that located each new plant at the lowest transportation cost position for utilizing straw that had not already been assigned to previously sited plants. At all scales of operation, the area required to supply straw increased linearly with plant size for the first 80 to 90% of the potential sites, with required collection distances doubling from the first 10% to 60% of the potential industry. The more uniform distribution of lower transport cost sites across all production regions for the smallest-sized (farm-scale) plants along with the shorter collection distances (lower transport costs) for this scale indicates the likelihood that farm profitability will be optimized by continued efforts to develop the necessary farm-scale technology.