117-41 Characterization of Drainage and Nutrient Transport Below the Root Zone of a Short Rotation Coppice Irrigated with Municipal Treated Waste Water In the Boreal-Parkland Transition Zone, Alberta, Canada.



Monday, October 17, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

ABSTRACT WITHDRAWN

Short Rotation Coppice (SRC) crops in combination with municipal treated waste water (waste water) irrigation is an emerging renewable energy source. It involves managing fast growing woody species like willow and poplar and using waste water to meet the nutrient and water demands of the plants.  Municipalities adopting these systems receive several benefits, mainly reduced treatment and energy costs. Diversion of waste water onto land improves water quality in the area by limiting the amount of nutrients, like nitrogen, from entering water bodies, decreasing pollution such as eutrophication. As found by many European countries, the SRC crops with wastewater irrigation approach is promising but there are environmental drawbacks including nutrient leaching to groundwater and sail salinization. Various nitrogen forms, like nitrate, are of concern due to impacts on human and environmental health, most notably methemoglobinemia in infants. Waste water contains salts which may lead to soil salinization in the long term if a leaching fraction is not applied.  The overall objective of this research is to assess ecosystem resilience and sustainability with repeated applications of municipal wastewater over the life cycle of a willow plantation.  The specific objective of the research was to quantify the nutrient transport below and within the root zone of a SRC plantation after 4 years of irrigation with waste water.  Various components of the water balance were monitored from May to Oct 2010 including soil water, precipitation, temperature and evaporation. Soil samples were gathered for site characterization and chloride analysis. Ceramic cup lysimeters were installed at various depths below the root zone to monitor nutrients in soil water. Drainage was determined using a soil water balance approach and a method based on the conservation of a non transforming, non absorbed solute, the Chloride Mass Balance approach. Both methods indicate positive and negative annual drainage amounts. Drainage was determined weekly using the soil water balance method and positive and negative drainage events occurred. The soil water below the root zone was analyzed for nitrate and dissolved organic carbon (DOC). There were no apparent differences in nitrate and DOC in the soil water between the control and wastewater irrigated zones. In both zones, the DOC decreased over the growing season.
See more from this Division: S01 Soil Physics
See more from this Session: General Soil Physics: II (Includes Graduate Student Competition)