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Economic Model of Deficit Irrigation

    The model calculates net income from a crop on a unit of land based on a quadratic crop water production function, amount of effective precipitation, irrigation efficiency, cost of the irrigation water supply, crop production costs, and revenue from selling the crop. The model includes potential income from leasing out saved irrigation water. All biophysical variables are defined in terms of the relative evapotranspiration. Net income is maximized by optimizing the amount of water consumed by the crop.

    Nitrogen Decision Aid

      The Nitrogen Decision Aid is a computerized program that predicts the amount of N mineralized from planting to side-dress or 5-leaf growth-stage. By applying just enough N-fertilizer to reach the critical soil nitrate concentration it is possible reduce this waste. This model is designed for Northern climates that will have some frost in the soil during the winter.

      Research, Education, and Economics Information System (REEIS)

        The Research, Education, and Economics Information System (REEIS) is a source of information on the research, education and extension programs, projects and activities of the U. S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA), the USDA Forest Service, the USDA National Agricultural Statistics Service, the U. S. Patent and Trademark Office, U. S. Census Bureau, and the U. S. National Science Foundation. The system enables users to measure the impact and effectiveness of research, extension and education programs based on data related to agricultural research; forestry research; students, faculty and degrees related to agriculture; USDA partner institution snapshots; Food and nutrition research; 4-H programs; and agricultural snapshots of each state. Internet links to related agencies, institutions, and data bases are also included.

        APEX – Agricultural Policy/Environmental eXtender Model

          Agricultural Policy/Environmental eXtender (APEX) has components for routing water, sediment, nutrients, and pesticides across complex landscapes and channel systems to the watershed outlet as well as groundwater and reservoir components. A watershed can be subdivided as much as necessary to assure that each subarea is relatively homogeneous in terms of soil, land use, management, and weather. APEX was constructed to evaluate various land management strategies considering sustainability, erosion (wind, sheet, and channel), economics, water supply and quality, soil quality, plant competition, weather, and pests. The routing of water, sediment, nutrient, and pesticide capabilities are some of the most comprehensive available in current landscape-scale models and can be simulated between subareas and channel systems within the model. APEX can perform long-term continuous simulations for modeling the impacts of different nutrient management practices, tillage operations, conservation practices, alternative cropping systems, and other management practices on surface runoff and losses of sediment, nutrients, and other pollutant indicators.

          NUOnet (Nutrient Use and Outcome Network) database

            The Nutrient Uptake and Outcomes (NUOnet) database will be able to help establish baselines on nutrient use efficiencies; processes contributing to nutrient losses; and processes contributing to optimal crop yield, nutritional and organoleptic quality. This national database could be used to calculate many different environmental indicators from a comprehensive understanding of nutrient stocks and flows.