Progress 10/01/03 to 11/23/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Statement of problem: Agricultural production, conservation efforts and sustainable utilization of natural resources are sensitive to climatic variations. Particularly in the Southern Great Plains, year-to-year variations in precipitation are pronounced, and persistent dry or wet conditions often result in environmental impacts and agricultural losses on the order of several billion dollars. Losses affect farmers and ranchers, the economic well-being of rural communities, the consumer through volatile prices and irregular supplies, and the natural resource base through excessive erosion, nutrient movement, and floods. In the past, the unpredictability of climate and weather limited our ability to optimize agricultural production under favorable climatic conditions, and to mitigate environmental
impacts under adverse conditions. Under unpredictable climate conditions, farm planning and management decisions generally are reactive and conservative, and opportunities for diversification, greater profits, and enhanced environmental stewardship are missed. Major objectives: The overall objective is to integrate climate change, variability, and forecast information into risk-based decision, management and conservation tools to enhance sustainability, promote stability, optimize productivity, and mitigate losses in agricultural production systems. Specific objectives are listed under Question 2. Associated National Programs and specific NP action plan components and sub-components: This research project contributes to the National Program on Global Change (NP204; 60%) and to the National Program on Water Quality and Management (NP201, 40%). Under the NP204 Action Plan this research contributes to Component IV "Changes in Weather and the Water Cycle at Farm, Ranch, and Regional
Scales," Sub-components "Changes in Water Availability," "Climate and Weather Variability and Extremes," and "Scaling of Climate Change to Field, Farm, Ranch, and Regional Scales." Under the NP201 Action Plan this research contributes to Component I "Agricultural Watershed Management," Sub-components "Climate and Weather Uncertainties, Risks, and Extremes," and "Water Scarcity and Drought Mitigation." Who benefits, how serious is the problem, and why the research matters: The primary users of this research are resource managers, producers, and service organizations of the agricultural infrastructure, such as crop insurance suppliers, emergency and risk management agencies, and fertilizer, seed, and chemical companies, all of which could potentially benefit from forecasts of the next season's demands, production and yields. Models and methodologies developed by this research will also be valuable to scientists and engineers in federal, state, and private institutions, consultants, and
action agencies involved in various aspects of climate impacts on agricultural production and environments. The problem is very serious because climatic variations drive and impact nearly every sector of the agricultural system and result in significant annual losses that affect farmers and ranchers, the economic well-being of rural communities, and the natural resource base through soil erosion, nutrient movement, water shortages, and floods. This research matters because it can deliver critical, climate-based planning tools for farmers, ranchers, agri-businesses, and natural resources managers that help mitigate the negative impact of climate variability and derive benefits from the positive aspects. 2. List the milestones (indicators of progress) from your Project Plan. Milestones do not exist for this project because it was developed before the OSQR review process was implemented. Instead, specific objectives of the project are listed. 1) Quantify climate variability, determine
predictability of climate variations, and establish the impact and implications of climate variations on agricultural productivity, agricultural water utilization potentials, and sustainability of agricultural production. 2) Evaluate the reliability of climate outlook products in relation to agricultural needs and planning horizons, determine the scale compatibility of climate outlook products to those of actual drought/flood manifestations, and establish the informational content and value of climate outlook data for application in agricultural planning and management. 3) Develop methodologies to disaggregate large time-scale climate outlook information into small time-scale climate information for agricultural applications, and define complementary agro-climatic information that meet the needs of decision making in agricultural management. 4) Develop planning and management tools for agricultural production and resources conservation that incorporate climate variability and outlook
information and that reflect risk and uncertainty associated with the inherent variability of long-lead climate forecasts. 3. Milestones: A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones die you fully or substantially meet in FY 2004, and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. Portions of Objectives 1, 2, 3 and 4 were scheduled to be addressed in FY 2004. For Objective 1, climate variability was quantified for climate regions in Oklahoma, Kansas, and Nebraska, and the impact and implications for water resources were completed. For Objective 2, the usefulness and reliability of the precipitation forecasts were evaluated for the contiguous United States. For Objective 3, a methodology for the space and time disaggregation of the climate forecasts to farm and field scales was developed. For Objective 4, initial concepts and approaches were developed, and preliminary
assessments made, because the scientists for this portion of the project were hired late in the project period. Objective 4 will continue to be addressed in the new project plan. B. List the milestones that you expect to address over the next 3 years. What do you expect to accomplish, year by year, over the next 3 years under each milestone? The following milestones are those of the approved Project Plan being established for FY 2005-2010. FY 2005: - Develop a method to adjust daily air temperature in stochastic weather generators to reflect air temperature forecasts, and implement the methodology into the weather generation computer program SYNTOR. This milestone is expected to deliver a weather generation program that can reflect seasonal climate departures as forecasted by NOAA's CPC. The primary customers are scientists and engineers. This technology will enable simulation of impacts of climate variability on agricultural production and the environment. - Develop
location-specific measures of usefulness and dependability of seasonal air temperature forecasts issued by NOAA's Climate Prediction Center (CPC) for all 102 forecast regions in the contiguous U.S., for the years 1997-2003. This milestone will identify regions where seasonal air temperature forecasts have high potential application utility. Customers that will benefit from this milestone are producers, water managers, and project scientists. The findings will help focus forecast-impact research and applications to regions with greatest potential for success. - Develop a prototype on-farm journaling tool where farmers record information about their thought process and factors that enter farm management decisions. This milestone will provide a tool that will help communicate the producer's decision making process to scientists who work in the area of decision making. Producers and scientists cooperating in science-based decision making are the main beneficiaries. A better
communication between producers and scientists will lead to a better assessment of application opportunities of climate forecasts in agricultural decision making. - Demonstrate the streamflow prediction capabilities of an Artificial Neural Network (ANN) model by application to the Ft. Cobb watershed in central Oklahoma. This milestone will uncover dominant rainfall-runoff variables and their appropriate spatial and temporal representation for a successful ANN training. Scientists, water resources engineers and reservoir managers are the primary customers to benefit from this milestone. The trained ANN will enable investigation of the utility of probabilistic climate forecasts and climate variability in water resources applications. FY 2006: - Identify multi-year precipitation and air temperature variations that are of relevance to the decision-making process. Determine statistical significance and exceedance probability curves for selected multi-year climate variations. This
milestone will define statistically relevant climate variations that should be investigated for agricultural and environmental impacts. As a result of this analysis, subsequent impact assessment can proceed in a focused manner with a higher probability of successful outcome. - Develop and test a method to disaggregate seasonal air temperature forecasts into monthly forecasts and to daily time scales using weather generation programs, and test the fidelity of generated weather statistics to the target seasonal forecast. This milestone will enable seasonal forecasts to be expressed at daily time scales which will support many crop and environmental assessment simulations in support of decision making. - Adapt, calibrate, and validate the CERES-Wheat model for fall-forage prediction in central Oklahoma. Develop weather and agronomic scenarios for the 2005 fall grazing season and conduct a test application of the CERES-Wheat model to provide decision support for the fall grazing
season. This milestone is necessary to set the stage for simulation of climate scenarios and assessment of decision alternatives in wheat-forage production. FY 2007: - Develop utility maps and tables for NOAA's CPC seasonal forecasts that identify areas and seasons of low/high potential for forecast applications. This milestone contributes to the technology transfer aspect of the project. Primary customers are producers, water managers, and conservation engineers. The milestone will provide users with forecast information that they can use in their own applications and decisions. - Develop weather and agronomic scenarios for the 2006 fall grazing season and conduct a full application of the CERES-Wheat model to predict fall-forage production, including grazing impacts, and to provide decision support for the fall grazing season. This milestone represents the first full application of the seasonal forecasts to assist in the planning and management of the fall wheat-forage and
grazing operation. The application will help producers make informed decisions under consideration of climate/weather uncertainties. - Design and implement a modeling structure for the 87000 km2 drainage basin of Lake Texoma to predict streamflow using Artificial Neural Network (ANN) model. This technical milestone is a pre-requisite to the application of ANN to such a large basin. It will set the stage for the subsequent prediction of Lake Texoma inflows and effective management of lake-surface levels. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2004: Forecast utility for streamflow prediction. This is a demonstration of a method to estimate watershed response to precipitation forecasts. This exploratory application is important because it provides an understanding of soil water conditions in the watershed and forecast duration under which forecasts are useful for streamflow prediction. Scientists at the
Grazinglands Research Laboratory conducted an exploratory watershed-model application to determine the potential to predict streamflow of a 33-km2 watershed in central Oklahoma given a precipitation forecast. They applied the Soil and Water Assessment Tool (SWAT) to simulate effects of wet, average, and dry soil water conditions, and wet, average, and dry precipitation forecasts of 1- and 3-month duration on streamflow response. Results showed that under dry and average watershed conditions a monthly precipitation forecast provided little streamflow prediction potential, while a 3-month forecast showed promise for streamflow prediction and water supply management. From this study, it was inferred that 3-month and longer forecasts can be useful for surface water resources management. B. Other significant accomplishment(s) during FY 2004, if any: Utility of seasonal air temperature forecasts. Seasonal air temperature forecasts for three months to a year in the future are issued
monthly by NOAA, but the utility of these forecasts had not been extensively evaluated for potential agricultural applications. A first method was developed to assess the utility of NOAA's seasonal mean air temperature forecasts and applied to identify regions, seasons, and conditions that have high potential utility for practical forecast applications. Initial findings of scientists at the Grazinglands Research Laboratory indicate that there are seasons and regions with potentially useful seasonal mean air temperature forecasts, and that temperature forecast departures from normal display different seasonal and regional patterns than the corresponding seasonal precipitation forecasts. Simulated erosion risk under climate change. This study indicated the risk of soil erosion in central Oklahoma could increase due to changing climate. This research can provide guidance to conservation professionals with respect to potential trends in soil erosion due to future climate change
scenarios, and the need for additional or different conservation efforts. A computer simulation was carried out to evaluate the potential impacts of climate change on soil erosion, surface runoff, and wheat production in central Oklahoma under three climate scenarios (60%, 80%, and 150% carbon dioxide increase and associated projected climate shifts). Results projected that soil erosion from wheat fields would increase in central Oklahoma under the investigated climate change scenarios, mainly because of an increase in anticipated precipitation variability. Conservation tillage and no-till practices kept soil loss to a minimum in these simulations, across all three climate scenarios. C. Significant Activities that Support Special Target Populations: Langston University Grassland Management Summit. (Attendees were primarily 1890's Land Grant employees, small farmers, underserved farmers. ) Scientists attended the conference, participated in breakout discussions, and presented
information at the Conference Tour on climate and water resources research relevant to grassland management. Hosted Dr. George DaBai, Director, Environmental Resources Center, Langston University, to present a seminar and discuss research collaboration opportunities. The Research Leader participated on a committee for Southern Great Plains Agricultural Resources Coalition that focuses on improved production and marketing of agricultural products to enhance environmental and economic sustainability of small farmers and rural communities in western Oklahoma. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Forecast prediction performance at regional scales. The predictions of NOAA's seasonal precipitation forecasts was evaluated on a region by region basis to help determine forecast utility for agricultural and water resources management. Evaluation of forecast utility is important to establish under what conditions the
forecasts can be beneficially applied in decision-making. Precipitation forecasts from 1997 through 2003 were analyzed and performance measures that capture predicted seasonal precipitation amount, direction and bias were developed. Forecast performance varied from one region to another across the continental United States. The area from California through the Desert Southwest to the Southeast has greater potential for forecast applications in agriculture than the Great Plains and the northeastern US. In regions where climate forecasts have demonstrated sufficient performance and utility, use of the forecasts in decision-making could reduce production risk and improve profitability in agricultural planning and management, as well as improve efficiency and reduce risk in management of water resources. This accomplishment relates to Component IV of the Action Plan of the National Program on Global Change, Section "Climate and Weather Variability and Extremes", Goal 4. Downscaling
forecasts to application scales. A methodology was developed to downscale seasonal precipitation forecasts issued by NOAA to monthly and daily time scales. This downscaling is important because it makes the forecasts applicable for local agricultural production management and conservation efforts. Scientists at the Grazinglands Research Laboratory, El Reno, OK, in collaboration with NOAA's Climate Prediction Center (CPC), refined a method to downscale 3-month precipitation forecasts to a monthly time scale, and scientists at the Grazinglands Research Laboratory, in collaboration with the ARS Grassland Soil and Water Research Laboratory, Temple, TX, developed a separate method to convert the monthly precipitation forecasts into daily precipitation values. This downscaled format of the precipitation forecasts makes them suitable for computer applications that project agricultural productivity or water resources, and establishes the risk associated with the uncertainty of the
forecasts. The transfer of the downscaling methodology for use by NOAA's CPC has been initiated, and the information can assist in timely and informed decision making regarding production management, farm profitability, and resource management. This accomplishment relates to Component IV of the Action Plan of the National Program on Global Change, Section "Climate and Weather Variability and Extremes", Goal 4. 1980-2000 precipitation increase in the Great Plains. The existence, extent and magnitude of decade-long precipitation variations in the Great Plains at the end of the 20th century have been brought to the attention of the scientific, engineering, agricultural, and water-resources management community. It is critical to identify such sustained variations in precipitation because they can have far-reaching economic and societal consequences through cumulative effects on weather-sensitive sectors of the economy and environment, such as agriculture, urban and industrial water
supply, hydro-electric power generation, transportation, recreation and ecosystem sustainability. The characteristics of the precipitation variations have been quantified for nine broad regions in the Great Plains between the Rocky Mountains and the Mississippi River, and it was found that in the final decades of the 20th century the majority of the Great Plains experienced the largest and longest increase in precipitation over the last 105 years. The findings of this research opened the doors to re-evaluation of the concept of a stationary climate, the recognition of the changing nature of risk, and the exploitation of opportunities in water resources and agricultural applications. This accomplishment relates to Component IV of the Action Plan of the National Program on Global Change, Section "Climate and Weather Variability and Extremes", Goal 1. Decade-long precipitation variations impact surface-water supply. Streamflow from watersheds in Oklahoma, Kansas, and Nebraska were
shown to respond sensitively to decade-scale variations in precipitation. A 10% change in decade-scale precipitation variation often resulted in a corresponding streamflow change exceeding 20%. Establishing the sensitivity of streamflow to decade-long precipitation variations exposed a potential vulnerability of surface-water supplies for municipal and industrial uses to sustained, multi-year below average precipitation. Scientists at the Grazinglands Research Laboratory analyzed variations of measured annual streamflow for 10 medium-sized watersheds in Oklahoma, Kansas, and Nebraska and related these to decade-long variations in regional precipitation. Water management agencies of the States of Oklahoma, Texas, and Arkansas have recognized the potential need for considering the impacts of decade-long precipitation variations into their long-term water-supply planning and management strategies, based on these findings. This accomplishment relates to Component IV of the Action Plan
of the National Program on Global Change, Section "Climate and Weather Variability and Extremes", Goal 1. Weather generation models for forecasts. Accessibility, usability, and transferability of new methodologies for downscaling monthly forecasts into daily weather is an integral component of this climate research. Scientists at the Grazinglands Research Laboratory have substantially modified and extended ARS's WGEN, USCLIMATE, and CLIGEN weather generators to produce daily weather that is representative of monthly precipitation forecasts. The first prototype computer program for the weather generator SYNTOR was written and tested. This technology is expected to be useful to scientists and practitioners alike to predict and analyze the impact of forecasted climate on agricultural productivity and resource conservation. This accomplishment relates to Component IV of the Action Plan of the National Program on Global Change, Section "Climate and Weather Variability and Extremes",
Goal 5. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Utility of NOAA's long-term seasonal forecasts, impact of decade-scale precipitation variations on surface water resources, and applications in crop and tillage systems are being transferred in the form of publications and presentations to our customers and producer organizations. No tangible technologies for field implementation are ready for transfer. However, methodologies and scientific results are becoming available for use by the scientific community. Broader adoption of seasonal forecast applications will also depend on user education on probability forecasts and how to make optimum use of these products with crop response and risk management. The difficulties inherent in delivering
forecast-based planning tools in timely fashion and in formats that are effective for producers' may represent the most significant constraint to adoption of anticipated products. The research and findings on the utility of streamflow prediction are being transferred in the form of publications in professional journals, presentations at professional meetings and workshops with customers. The primary end user is the scientific community and water resource managers. The major constraint to the adoption of the technology is the exploratory nature of this research. Based on the findings to date, a focused research application is planned to address this issue on a context of a reservoir operation. The research methodology to assess the impacts of CO2 change and associated climate shifts on erosion risks and management are being transferred in the form of publications in professional journals. The primary end user is the scientific community, natural resource managers and policy makers.
The major constraint to adoption and durability of the technology is the uncertainty with regard to events that may occur 50 and more years in the future. Data sets generated from the network of climate/water stations on the Little Washita River Experimental Watershed are made available to the public through Internet access. The most basic constraints to accessibility to these data are knowledge of file transfer procedures and the use of software to read the digital data. The website for the meteorological data is http://grl.ars.usda.gov/micronet. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Presentations: Schneider, J. M., and J. D. Garbrecht. How Good are the Seasonal Predictions of Total Precipitation for Oklahoma? Oklahoma Water Symposium 2003, October 29-30, 2003, Stillwater, OK. Garbrecht, J. D., and J. M. Schneider. Long-term Variability in Oklahoma Precipitation and Water Resources
Availability, Oklahoma Water Symposium 2003, October 29-30, 2003, Stillwater, OK. Schneider, J. M. Utility of NOAA/CPC Seasonal Precipitation Forecasts, Workshop on Climate Variability and Seasonal Climate Forecasts and their Application in Agricultural Decision Making, November 14, 2003, USDA-ARS Grazinglands Research Laboratory, El Reno, OK. Schneider, J. M., and J. D. Garbrecht, 2003. Climate Variations and Forecasts Project. Southern Plains Regional Integrated Science Assessment (RISA) Workshop, December 10-12, 2003, Grapevine, TX. Schneider, J. M., 2004. Utility of NOAA/CPC Seasonal Precipitation Forecasts. USDA/OCS/NWS Climate Products Strategy Session, January 28, 2004, National Weather Service Forecast Office, Tulsa, OK. Garbrecht, J. D. 2004. Long term Trends in Red River Streamflows. Presented to the Red River Compact Commission, and to the Arkansas-White- Red Basins Inter-Agency Committee. Pottsboro, Texas, April 2004. Schneider, J. M. 2004. The Track Record of
Seasonal Climate Forecasts for Oklahoma. 2004 All Oklahoma Chapter Annual Conference, Soil & Water Conservation Society, June 16-18, 2004, Stillwater, OK. Garbrecht, J. D. 2004. Long-Term Variability of Oklahoma Precipitation and Water Resources Availability. Presentation at USGS Water Resources, Oklahoma District for a general customer audience. The project and research findings on decade-scale climate variability, seasonal forecasts, and water resources and agricultural impacts have been presented to visitors to the Grazinglands Research Laboratory, El Reno, Oklahoma, as well as to producer organizations, civic groups, and also to participants of locally organized workshops for customers. On the subject of downscaling of monthly forecasts of climate change, a seminar was presented to a group of scientists, engineers, and graduate students in the Institute of Soil and Water Conservation at the Chinese Academy of Sciences. Publications: Pons, L. Less Rain in the Forecast? Tailored
climate data may help water managers be prepared, Agricultural Research, Vol. 52, No. 7, July 2004, pp. 8-9, U.S. Department of Agriculture - Agricultural Research Service.
Impacts
(N/A)
Publications
- GARBRECHT, J.D., SCHNEIDER, J.M., ZHANG, X.J. DOWNSCALING NOAA'S SEASONAL PRECIPITATION FORECASTS TO PREDICT HYDROLOGIC RESPONSE. CD-ROM. BOSTON, MA: AMERICAN METEOROLOGICAL SOCIETY. 2004.
- SCHNEIDER, J.M., GARBRECHT, J.D. USEFULNESS OF RECENT NOAA/CPC SEASONAL TEMPERATURE FORECASTS. CD-ROM. BOSTON, MA: AMERICAN METEOROLOGICAL SOCIETY. 2004.
- GARBRECHT, J.D., SCHNEIDER, J.M. VARIATIONS IN PRECIPITATION IN THE GREAT PLAINS: THE PAST 100 YEARS. Proceedings of the Water and the Future of Kansas Conference. 2003. p. 14.
- GARBRECHT, J.D., SCHNEIDER, J.M., ZHANG, X.J. DOWNSCALING NOAA'S SEASONAL CLIMATE FORECASTS TO PREDICT HYDROLOGIC RESPONSE. AVAILABLE FROM: http://ams.confex.com/ams/84annual/18hydro/abstracts/68223.htm AMERICAN METEOROLOGICAL SOCIETY PROCEEDINGS [2003].
- GARBRECHT, J.D. REVIEW OF 'MATHEMATICAL MODELS OF SMALL WATERSHED HYDROLOGY AND APPLICATIONS' BY VIJAY P. SINGH AND DONALD K. FREVERT. JOURNAL OF HYDRAULIC ENGINEERING. 2003. v. 129. p. 558-559.
- SCHNEIDER, J.M., GARBRECHT, J.D. SEASONAL CLIMATE PREDICTIONS AND THEIR IMPLICATION FOR AGRICULTURAL MANAGEMENT IN THE CENTRAL GREAT PLAINS. Proceedings of the Water and the Future of Kansas Conference. 2003. p. 14.
- GARBRECHT, J.D., SCHNEIDER, J.M. CHANGING ANNUAL AND SEASONAL PRECIPITATION PATTERNS: AN ISSUE FOR WATER RESOURCES MANAGEMENT? CD-ROM. RESTON, VA: AMERICAN SOCIETY OF CIVIL ENGINEERS, EWRI. 2002.
- SCHNEIDER, J.M., GARBRECHT, J.D. A BLUEPRINT FOR THE USE OF NOAA/CPC PRECIPITATION CLIMATE FORECASTS IN AGRICULTURAL APPLICATIONS. PROCEEDINGS OF THE AMERICAN METEROLOGICAL SOCIETY. 2001. p. J71-J77.
- GARBRECHT, J.D., ZHANG, X.J. GENERATING REPRESENTATIVE SEQUENCES OF DAILY PRECIPITATION FOR AGRICULTURAL SIMULATIONS. JOURNAL OF APPLIED ENGINEERING IN AGRICULTURE. 2003. v. 19(4). p. 423-429.
- ZHANG, J. SIMULATING WINTER WHEAT PRODUCTIVITY UNDER VARIOUS CLIMATE SCENARIOS. CD-ROM. MADISON, WI: AMERICAN SOCIETY OF AGRONOMY. 2003.
- ZHANG, X.C., NEARING, M.A., POLYAKOV, V.O., FRIEDRICH, J.M. USING RARE- EARTH OXIDE TRACERS FOR STUDYING SOIL EROSION DYNAMICS. SOIL SCIENCE SOCIETY OF AMERICA JOURNAL. 2003. v. 67(1). p. 279-288.
- Rogers, J., Brown, G.O., Garbrecht, J.D., editors. 2004. Water resources and environmental history. Reston, VA: American Society Of Civil Engineers.
- Garbrecht, J.D., Schneider, J.M., Van Liew, M.W., Lall, U. 2004. Utility of streamflow forecasts derived from seasonal precipitation forecasts. In: Proceedings of the Environmental and Water Resources Institute World Congress, June 27-July 1, 2004, Salt Lake City, UT. 2004 CDROM.
- Schneider, J.M., Garbrecht, J.D. 2004. Regional performance of NOAA/CPC seasonal climate temperature forecasts. In: Proceedings of the Environmental and Water Resources Institute World Congress, June 27-July 1, 2004, Salt Lake City, UT. 2004 CDROM.
- Garbrecht, J.D., Garbrecht, G.K. 2004. Siltation behind dams in antiquity. In: Rogers, J.R., Brown, G.O., Garbrecht, J.D., editors. Water Resources and Environmental History. Reston, VA: American Society Of Civil Engineers. p. 35-43.
- Garbrecht, J.D., Garbrecht, G.K. 2004. Sedimentation of harbors and counter-measures in the greek and roman era. In: Rogers, J.R., Brown, G.O., Garbrecht, J.D., editors. Water Resources and Environmental History. Reston, VA: American Society Of Civil Engineers. p. 11-20.
- Zhang, X.J., Nearing, M.A., Garbrecht, J.D., Steiner, J.L. 2004. Downscaling monthly forecasts to simulate impacts of climate change on soil erosion and wheat production. Soil Science Society of America Journal. 68:1376-1385.
- Steiner, J.L., Schneider, J.M., Garbrecht, J.D., Zhang, X.J. 2004. Climate forecasts: emerging potential to reduce dryland farmers' risks. In: Rao, S. C., Ryan, J., editors. Challenges and Strategies of Dryland Agriculture. Special publication number 32. Madison, WI: Soil Science Society of America. p. 47-65.
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