1a.Objectives (from AD-416):
Problems to be addressed through this agreement include the following four areas: 1. Improving our understanding of the aggregate effects of conservation practices at the watershed scale; 2. Improving our ability to select and place conservation practices on the landscape for maximum effectiveness; 3. Improving conservation practices to better protect water resources; and 4. Maintaining the effectiveness of conservation practices under changing climate and land use.
1b.Approach (from AD-416):
Improving our understanding of the aggregate effects of conservation practices at the watershed scale: 1. Field studies to develop remote sensing tools to better evaluate cover crop performance (CB/ACP). 2. Develop models/decision support tools to assess the effectiveness of cover crops (CB/ACP) and other BMP’s (All) at the watershed scale. 3. Enhance the landscape version of SWAT to better represent field-to-basin scale processes (All).
Improving our ability to select and place conservation practices on the landscape for maximum effectiveness:
1. Develop mapping techniques for placing specific practices within watersheds based on terrain and soils data. 2. Develop methods of terrain analysis for improved mapping of soil wetness in glacial terrain. 3. Validate the CEAP National Assessment conducted with SWAT at multiple scales. 4. Assess and compare the trade-offs of no-till adoption, and support the development of
nutrient management recommendations for water quality protection, at the watershed scale.
Improving conservation practices to better protect water resources:
1. Quantify nutrient management effects on water quality at field and watershed scales. 2. Watershed scale studies to systematically validate phosphorus site assessment tools in support of NRCS 590 (nutrient management) standard.
3. Watershed scale assessment of combined conservation practices.
Maintaining the effectiveness of conservation practices under changing climate and land use: 1. Use reservoir sedimentation, land use change, and climate information to anticipate future reservoir sedimentation and needs for additional conservation under changing climate. 2. Enhance SWAT model routines for urban landscape BMPs. 3. Apply erosion (WEPP, etc.) and water quality (WEPP-WQ, etc.) models to catchments ranging from field- to farm-size and watershed scale, to assess the impacts of current and alternative land management systems and conservation practices under current and future climates.
Model intercomparisons have been conducted for maize and wheat models and are underway for rice, sugarcane, potato, soybean, and millet. Data sets have been assembled for each crop from the international research community in order to provide a range of production environments and production levels. In the maize and wheat trials a suite of models produced a more robust estimate of production than any single model. Throughout the course of the model comparisons it was discovered that the interactions of carbon dioxide-temperature-water stress on plant growth and yield are not adequately quantified and the incorporation of these interactions in crop models is not well understood and efforts are underway to evaluate how crop models can incorporate new understanding of experimental observations and is the subject of a workshop at a 2013 tri-society annual meeting and a monograph is planned from this workshop. A workshop on North America production systems was held in September 2012 to determine how climate will affect crop production and the potential economic impacts and forms the foundation for future assessments.