Water quality of irrigation sources. Characterize the quality of alternative or non-traditional water sources in different regions of the U.S. Determine water quality parameters and levels that are most limiting for intensive plant production systems and evaluate treatment and management options to overcome the limiting factors. Improved irrigation management. Determine the water quality and quantity requirements of different plant production systems with varied container sizes and environmental conditions. Compare irrigation methods (e.g. overhead, spray stakes, drip irrigation, subirrigation) to determine how they affect total water use, plant growth and quality, and runoff water quality. Identify methods to reduce water use, leaching, and runoff and quantify results from more efficient techniques. Develop new and optimize existing irrigation methods that are easily deployed in intensive plant production systems to provide growers with real-time information regarding water requirements and environmental conditions of their crops. Evaluate the compatibility of low-quality water with irrigation methods and systems. Crop production runoff management. Address research and extension needs related to enhancing containment of production runoff and improving recycled water management by identifying and characterizing critical control points within production systems, further developing chemical, physical, and biologically-based water treatment technologies and providing BMP guidelines to mitigate adverse effects of sediment, agrichemicals, and pests in production runoff, irrigation reservoirs, and other water sources. Urban stormwater. Improve the design of biological urban stormwater systems to better reduce and remediate stormwater runoff from various sources, addressing issues of water volume, intensity, quality, and reuse. Focus on the use of novel biological and engineered systems and materials (e.g. organic/inorganic substrates and amendments) which mitigate runoff and pollutants, as well as the use of woody and herbaceous plants, in single or combined (treatment train approach) systems in greenhouse, nursery, and urban production environments. Soilless culture and nutrient management. Assess physical, chemical, and biological properties of soilless culture systems or components for their impact on plant health and vigor, water reuse and subsequent use efficiency, nutrient delivery and retention, crop fertility, and environmental impact for a variety of important controlled environment and urban crops throughout the U.S. Expand our knowledge of how soilless culture systems affect plant productivity, root growth, plant pathogen or weed pressure, and dynamic physicochemical properties including hydraulic conductivity, pH, cation and anion exchange, plant-water availability, gas exchange and moisture retention.