Soil Sensitivity to Acidification in Asia: Spatial and Temporal Trends

Although previous studies have found exceedance of steady-state critical loads for soil acidification for sensitive soil types in Asia, there is little evidence of impacts outside of China. This paper tests the hypothesis that buffering of acidic deposition is delaying the onset of acidification effects. The time development of soil acidification is estimated for Asian soil types by calculating the time required for a decrease in base saturation in response to acidic inputs to a threshold of 20%. In all assessments parts of southern China with high acidic deposition are most at risk from soil acidification. The results show that, apart from southern China, soil acidification is not a widespread problem in Asia and only sensitive soil types in areas of S and SE Asia may acidify on a 0-25 year timescale depending on individual site abiotic and biotic characteristics and management. The rate of soil acidification is shown to be highly dependent on biological acidification (base cation uptake by vegetation and removal by harvesting) and nitrogen and sulfur retention in ecosystems as well as the deposition of sulfur, nitrogen and base cations. The results highlight the importance of ecosystem management in addition to deposition controls in preventing soil acidification in Asia

HICKS Kevin;  KUYLENSTIERNA Johan C. I.;  OWEN Anne;  DENTENER Franciscus;  SEIP Hans-Martin;  RODHE Henning; 

2008-07-25

ROYAL SWEDISH ACAD SCIENCES

JRC42417

0044-7447,