Tuesday, November 6, 2007
218-4
Measuring Soil Quality in Planted Forests Across an Environmental Gradient in New Zealand.
Alicia L. Kiyvyra1, Stephen H. Schoenholtz2, James Burger2, Peter Clinton3, Graham Coker3, and Michael Watt3. (1) Oregon State University, Dept. of Forest Engineering, Corvallis, OR 97331, (2) Forestry Dept., Virginia Tech, 210 Cheatham Hall, Blacksburg, VA 24061, (3) Ensis, Christchurch, New Zealand
Measurements of forest soil quality can provide foresters with the tools to assess important sustainability elements or processes of their managed lands. Previous research has identified important soil quality indicators which include: total C, total N, total P, C:N, mineralizable N, pH, Olsen P, bulk density, macroporosity, and depth of A horizon. Thus, a quantitative assessment of soil indicators which describe key soil processes could be used to evaluate the maintenance of soil function/site potential over time. Basic physical and chemical soil properties were measured at 35 high density (40,000 stems ha-1) site quality plots established across an environmental gradient in New Zealand to test the effects of tree species (Pinus radiata and Cupressus Lusitanica), disturbance (high and low soil disturbance), and fertilizer (no fertilizer and unlimited fertilizer) on site and soil quality. Nutrient cycling processes (N mineralization, litter and wood decay, and daily soil water) were examined across a subset (10 sites) of the site quality plots. The objective of this research is to investigate the relationships among key soil quality indicators and the nutrient cycling processes they represent across a strong environmental and edaphic gradient. Results from this research may provide the basis for development of a soil quality model for forest plantations in New Zealand.