2012 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.
Progress was made on all 3 objectives, all of which fall under National Program 216, Component I, Agronomic Crop Production Systems, and Component 4, Integrated Technology and Information to Increase Customer Problem Solving Capacity. This project focuses on Problem 1.B, the need to produce energy crops in different agricultural regions of the U.S. and to identify 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 increase agricultural efficiency and economic competitiveness. Under objective 1.B1, we made significant progress in using a farm-scale gasification reactor to convert Kentucky bluegrass seed mill screenings into syngas. The syngas had sufficient energy and quality to replace 35% of the diesel fuel required to power a 100 kW generator sized to provide electricity for the entire farm. The heavy metal and organic compound content of char produced by process was below the level considered deleterious for soil or plant productivity. In subsequent greenhouse experiments, the char improved the productivity of wheat when used as a soil supplement. The char improved water retention of soil and increased soil pH, reducing aluminum toxicity. To address objective 4D we developed models for production of grass seed crops within Soil Water Assessment Tool (SWAT) that incorporated realistic dates for common management activities. These models provided better estimates of nitrate and sediment yield than the default options for National Land Cover Database (NLCD) 2001 land uses. Applying these models to the years for which we have detailed crop/land use and water quality data, we validated the existence of low, medium, and high Nitrogen-impact sub-basins previously identified in the Calapooia River Basin, Oregon. These results informed producers and policymakers of the relative contributions of farming practices and local weather conditions to the movement of nitrogen and sediment into surface waters in western Oregon, many of which are impacted by listings of threatened or endangered salmonid fishes. Crop and management operations modeled in SWAT are useful in predicting the magnitude of water quality responses to changes in crop production and management practices used or encouraged by government programs. (Since there is almost no participation in federal conservation programs in the Willamette Valley, we evaluated the effect of an environmental incentive policy. In this policy a water quality objective is specified using a biophysical model and a second objective, farm profit, is specified using a farm level optimization model.) We calculated the trade-offs between farm profit and nitrate loadings to evaluate alternative green taxes targeted at the farm and watershed levels we identified optimal solutions which identified policy offering trade-offs among objectives that were better (higher profit, less nitrate loading) and more cost effective than could be achieved with a watershed level targeting of the green tax. We used the hybrid genetic algorithm and found it was the optimal set of solutions.
Prediction of agricultural related nitrogen and sediment movement to streams. Comprehensive hydrologic models such as the Soil Water Assessment Tool (SWAT) are vital for assessing the impact of varying concentrations of Nitrogen or sediment within waterways over time and for converting those measurements into estimates of the impact under different weather or cropping scenarios. Crops and management operations modeled in SWAT are also useful ways to determine the magnitude of water quality responses to hypothetical changes in crops selected for production and management options available for use or encouraged by government programs. ARS researchers at Corvallis, Oregon, developed models for production of western Oregon grass seed crops within SWAT that incorporated realistic dates for common management activities such as planting, fertilizing, and harvesting, and found that these models provided better estimates of nitrate and sediment yield than the default options for National Land Cover Database (NLCD) 2001 landuses. Applying these models to the years for which there was detailed crop/land use and water quality data validated the existence of low, medium, and high N-impact subbasins previously identified in the Calapooia River Basin. These results informed producers and policymakers of the relative contributions of farming practices and local weather conditions to the movement of nitrogen and sediment into surface waters in western Oregon.
Agriculture conservation practices increase amphibian habitat accessibility. Agricultural ecosystems are potential habitat for amphibians in areas where historical aquatic breeding habitats and upland hibernacula (shelter of hibernating animal) have been lost and can also act as barriers to amphibian movement between aquatic breeding habitats and upland overwintering hibernacula. Conservation efforts such as crop residue management practices, riparian buffers (inhabiting or situated on the bank of a river), and reduced tillage practices have the potential to mitigate the impacts of agriculture on local species by improving habitat quality and connectivity in agriculturally dominated systems. ARS researchers at Corvallis, Oregon, analyzed the effect of field level conservation efforts employed in the Calapooia watershed, (Central Willamette Valley) in Oregon, on amphibian species diversity at multiple spatial scales. There was a positive association between amphibian species diversity and the percentage of land in a conservation practice at the sub-basin scale, but not at smaller spatial scales (e.g., 150, 250, 500, and 1,000 meter buffer zones from the breeding sites). This study suggested that conservation practices implemented on grass seed cropping systems increase habitat connectivity for local amphibian species, allowing for greater species diversity at aquatic breeding sites in these agricultural landscapes.
A more powerful execution of modeling behavior. The linkage between economic and environmental models has been limited because each model functions independently. This type of modeling approach is limited in power. ARS researchers at Corvallis, Oregon, introduced a revolutionary new method that links models in such a way that independent models exchange information throughout their complex computations. Researchers implemented this method by using a hybrid genetic algorithm that linked a full biophysical model with an economic optimization model to find the optimal trade-offs between multiple objectives. The hybrid genetic algorithm allows for the optimization of an economic model to construct a competing objective to environmental objectives specified by the biophysical model. Making the optimization of economic objectives an integral part of the calculation of trade-offs simulates the response of producers to a policy. Also, it provides a basis for policymakers to seek solutions to environmental issues while preserving agricultural profitability.
Gasification char has utility as a soil amendment. The effects of char produced from gasification of Kentucky bluegrass residues on plant productivity when used as a soil amendment, and consequently, its utility as a value-added product was unknown. ARS researchers at Corvallis, Oregon, conducted greenhouse trials which proved that when used as a soil amendment, the char increased soil pH, reduced the uptake of aluminum by wheat plants, and improved biomass production. Chemical analyses of the char also demonstrated that returning char to the production fields sequestered significant quantities of carbon and returned potassium and phosphate to the soil. This accomplishment showed that char produced by on-farm gasification has economic and agronomic value as a soil amendment and will enhance the economic feasibility of on-farm gasification of agricultural residues.