Project Number: 5358-12210-003-07
Project Type: Grant

Start Date: Sep 19, 2007
End Date: Mar 31, 2009

Objective:
1. Develop a technique to determine nutrient content and longevity. 2. Determine the duration that micro- and macro-nutrients will be available within sufficient range for plant growth. 3. Correlate nutrient longevity with irrigation volume applied. 4. Determine metal speciation in effluent using chemical equalibrium model software to make inferences on reactivity of metals, thus plant availability and environmental impact.

Approach:
Douglas-fir bark and Canadian sphagnum peat will be wetted to container capacity and used to pack 3.8 L columns. These columns are equivalent in size to #1 nursery containers. Initial and final samples of each substrate will be analyzed for total nutrient content and organic matter. In addition, the base of each column will be packed with fine glass beads to create a hanging column, ensuring that not point in the substrate profile will remain saturated and undergo reduced conditions. Influent will be added via pulse irrigation at a rate 85 mL/hr. Effluent pH will be measured at each collection intervals. Effluent aliquots will be filtered and stored frozen before analysis with inductively coupled plasma optical emission spectrophotometer to determine total metal concentration and colorimetric spectrophotometer to determine nitrate, ammonium, and dissolved reactive phosphorous. Dissolved organic carbon and total nitrogen will be determined with a C/N analyzer. Nutrient content will be quantified using effluent volume and nutrient concentration data. Metal speciation will be determined with thermodynamics using Visual MINTEQ chemical equilibrium model software. Documents Grant with Oregon State University.