The sensitivity of ecosystems to acid inputs in the Hunter Valley, Australia

✍ Scribed by B. Robinson; H. Malfroy; C. Chartres; K. Helyar; G. Ayers

• Publisher: Springer Netherlands
• Year: 1995
• Tongue: English
• Weight: 632 KB
• Volume: 85
• Category: Article
• ISSN: 0049-6979
• DOI: 10.1007/bf00477228

✦ Synopsis

This study assesses the importance of H + generation in the Hunter Valley from land use and coal-fired power stations. The Hunter Valley is a temperate coastal landsystem approximately 150 km north of Sydney. "Land uses include forestry and national parks, grazing and farming, coal mining, coal-fired electricity generation and manufacturing The H + generated from land use is estimated from land suitability classes. Wet deposition is estinrated from 10 years' rainwater chemistry data and dry deposition is estimated from modelled SO~ concentrations and a deposition velocity constant. The pH and pH buffer capacity of 51 soils were measured.

H + loads flora land use ranged from 0.05 to 12 kmol H+/ha/year for forests and prime agricultural land, respectively. Estimated H + deposition ranged from 0.27 to 0.65 kmol H+/ha/year, depending on the distance and direction from the power stations. The H + load that will lead to critically low pH values in 50 years is 0.27, 0.60, 1.77 and 2.14 kmol H+/ha/year for four broad soil classes. The two most sensitive classes, with target loads of 0.27 and 0.60 kmol If&a/year, occupy 26% and 56% of the study area respectively. Although the total contribution of H + from land use is larger than from deposition (970 vs. 220 Mrnol H+/year), H + deposition may be important on low fertility nonagricultural soils with low pH buffer capacity. More detailed study of the areas with sensitive soils is warranted.