EVALUATING THE EFFECTS OF FOREST LIMING IN APPALACHIAN WATERSHEDS: CHEMISTRY AND MULTI-ISOTOPE APPROACHES
Open Access
- Author:
- Kim, Hyeon Jeong
- Graduate Program:
- Forest Resources
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- February 22, 2007
- Committee Members:
- William Edward Sharpe, Committee Chair/Co-Chair
David Russell Dewalle, Committee Member
James Anthony Lynch, Committee Member
Richard Rudolph Parizek, Committee Member
Charles Heckman Strauss, Committee Member - Keywords:
- forest liming
mean water residence time
strontium isotope
water chemistry
oxygen-18 isotope
paired watershed approach - Abstract:
- An investigation was conducted to determine the short-term effects of liming on soils, soil solutions, and streamwater at acidified watersheds in the northeast United States, using an integrated set of hydrometric, hydrochemical, and multi-isotope measurements. Additionally, this research compared timing of liming response on chemistry with estimated residence time as of water in soil and on basins. Based on Before-After-Control-Impact (BACI) design, coarse-grained dolomitic limestone sand was applied at a rate of 5 t ha-1 over the Laurel and 90 Degree watersheds in fall 2003 and 2004 and over six soil plots (15.2 meter by 9.1 meter) within the same watersheds in summer 2005. The adjacent Merrill and Tick watersheds served as control watersheds. Within four months after liming application, mineral A horizon soils showed improvement in nutrient conditions such as increased soil pH, exchangeable base cations, and base saturation. Using 18O in water as a tracer, the mean residence time of soil water was estimated as about 2-4 months. In agreement with this estimated residence time, soil solution at 30 cm depth had increased pH, conductivity, acid neutralizing capacity, and concentrations of Ca and Mg, as well as Ca/Sr, Mg/Sr, and Ca/Al molar ratios. At the watershed scale, two treated watersheds had improved drainage water quality, with increased pH, conductivity, acid neutralizing capacity, and concentrations of Ca and Mg, as well as decreased Al during the 23-month monitoring period following application. Using 18O in water tracer, the estimated mean residence time of streamwater at the 90 Degree watershed was about one year, approximately the time lag chemical response to treatment. At this watershed, strontium isotope in water results also indicated a pattern of decrease in streamwater 87Sr/86Sr ratio 16 months after liming. This study showed that; 1) the estimated mean residence time of water at the study watershed generally agreed with the water quality results and the strontium isotope results; 2) the 87Sr/86Sr ratio was very useful as an isotopic solute tracer of liming; and 3) forest liming treatment rapidly improved soil nutrient conditions and drainage water quality on the treated watersheds.