Location: Forage Seed and Cereal Research2011 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.
3. Progress Report
Progress was made on all three objectives and their subobjectives, all of which fall under National Program 215, Component I, Agronomic Crop Production Systems, and Component 4, Integrated Technology and Information to Increase Customer Problem Solving Capacity. Progress on this project focuses on Problem 1.B, the need to know how to best produce energy crops in different agricultural regions of the U.S. and the impacts of energy production on whole-farm economics and natural resource quality, and on Problem 4.B, the need to determine the technical limits and feasibility of integrating new technologies to ensure that their use will increase agricultural efficiency and economic competitiveness. Under Objective 1B1, we made significant progress by collaborating with a research team from the private sector to demonstrate that a farm-scale gasifier produced sufficient quantities of medium heating value syngas to replace 75% of the diesel fuel required to power a 100 kW generator. We also established greenhouse trials to evaluate the utility of biochar, a recyclable byproduct from the gasification process, as a soil amendment to regulate soil pH and enhance soil fertility with potential cost saving benefits to the producer in reduced fertilizer and lime expenditures. To address the goals of Objective 4B1, we developed a novel way to calculate the best trade-offs that are possible between farm profit and water quality resulting from implementation of conservation practices. This new approach enables stakeholders to compare different best outcomes for all possible combinations of farm profit and water quality.
1. On-farm energy production. Energy production from farm waste would enhance profitability. ARS scientists from Corvallis, Oregon, collaborated with a research team from the private sector and demonstrated that a farm-scale gasifier produced sufficient quantities of medium heating value syngas to replace 75% of the diesel fuel required to power a 100 kW generator. Biomass residues generated from a seed cleaning mill were gasified to produce syngas and char, and the syngas was routed to a diesel powered generator that is sized to provide sufficient quantities of electricity to supply the entire farm, including the seed cleaning mill. Further research is required to clean the syngas to enable long-term electricity production by the generator, but ARS scientists demonstrated that, based on the quantity and distribution of straw and mill cleanings in the Pacific Northwest, there is a potential market for over 6200 similar-sized units. Completion of this research will provide manufacturing and operational opportunities for rural communities in the region and provide on-farm control of power-related production expenses.
2. 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 can be used as soil amendment without undue harm to grass and wheat plant growth. One characteristic of biochar favorable to optimum plant growth is alleviating harmful soil acidity effects. In addition, if implemented on-farm, these amendments would be a value-added recycling of useful minerals critical for healthy crop growth and reducing fertilizer inputs.
3. Ammonium fertilizers for use in grass seed production. Since 2002, Nitrogen(N) fertilizer prices have risen sharply and contributed to reducing farm cash returns. Pacific Northwest Kentucky bluegrass (Poa pratenses L.) seed growers have sought relief from high fertilizer costs associated with using ammonium nitrate by moving to regionally less traditional N sources that cost less. Ammonium sulfate and urea are two N fertilizer alternatives, but use of ammonium-based fertilizers can lower soil pH and reduce the availability of certain essential plant nutrients required for normal crop growth or promote plant toxicity by releasing undesirable soil elements. We evaluated the effects of using ammonium and nitrate nutrition on five Kentucky bluegrass grown for seed at five U.S. Pacific Northwest locations and showed that ammonium-based fertilizers could be used without affecting seed yield. Possible long-term impacts on soil pH may become apparent with continued use of ammonium-based fertilizers. This accomplishment enabled the development of a set of recommendations for economical fertilizer use along with field monitoring of soil pH and application of soil amendments (e.g., lime or biofuel generated ash) to mitigate soil pH changes.
4. Straw distribution defines optimum scale and location of biofuel conversion sites. Agricultural residues like straw that are already being produced under existing cropping systems are non-food biomass that has potential as feedstock for bioenergy production. These cellulosic residues are generally present in relatively low densities across the landscape and in many cases, require a more distributed system to enable their economical conversion to energy. ARS scientists in Corvallis used remote sensing of grass seed and cereal production across the Pacific Northwest to identify optimal locations for conversion facilities operating at three contrasting scales to achieve the lowest cost for transporting the biomass to the plant. Different scales of operation are appropriate depending upon the distribution and quantity of straw available within any given location. This accomplishment enabled the effective siting of appropriate scale facilities to reduce transportation costs and maximize farm profitability.
5. Calculation of optimal environmental and economic trade-offs. Non-point source pollution from farming can be reduced, but it almost always costs the farmer in reduced production or costs for conservation practices. ARS researchers at Corvallis, Oregon, adapted a genetic algorithm approach to develop a novel way of calculating the best trade-offs that are possible between farm profit and water quality resulting from implementation of conservation practices. This approach enabled producers and policymakers to compare different best outcomes for all possible combinations of farm profit and water quality. This improved approach differs from the more common method of analyzing "scenarios", where a given scenario may not describe the best available trade-off. This approach is important for developing policy that protects regional water quality while enabling continued producer profitability.
6. Impact of landuse patterns and agricultural practices on water quality. Nutrients and soil loss from agricultural fields represents inefficiency in agronomic practices, potential sources of damage to downstream ecosystems, and both public and private treatment expenses to meet drinking water standards. ARS researchers at Corvallis, OR, found that seasonal patterns in the concentration of nitrate leaving multiple sub-basin drainages in western Oregon were similar in timing but not magnitude for conditions ranging from nearly 100% forest on steep slopes to nearly 100% grass seed agriculture on level ground. The peak export of nitrate occurred with the arrival of heavy rains in late fall through early winter, a consequence of high rates of nitrogen mineralization and limited plant uptake during the normal late summer through early fall dry period in western Oregon. Prompt losses of nitrogen shortly after the normal period for fertilizer application in early spring were generally much smaller than the late fall losses. These results informed producers and policymakers of the extent of contribution of land-use and local weather conditions on how nitrogen makes its way into surface waters in western Oregon cropping systems, a process very different from cropping systems in the Midwest where corn and soybeans dominate.
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