Impact Of Acid Deposition On The Soil Acidification And Plant Ecophysiological Characteristics In Mt. Taishan

According to the sampling sites at the Mt. Taishan during the second national soil investigation (1980's) of China, two groups of soil samples were collected from Mt. Taishan in November 2008 and May 2009, separately. The soil samples were analyzed according to same analyzing methods in 1980's. The results show:(1) Compared with 1980's, the pH of soil samples collected from the sites lower than zhongtianmen do not have significant change, but the decrease of pH at the sites higher than zhongtianmen is significant. Meanwhile the exchangeable Al3+and H+ had increased, and base saturation(BS) had decreased in soil samples of all soil sampling sites compared with data in 1980's. This phenomenon indicates the trend of the soil acidification at different altitude is obvious. (2)The pH of soil samples did not show significant change between November 2008 and May 2009. The exchangeable Al3+ and BS of soil samples shown much more changes at the high altitude sites than the two indices at the low altitude sites between November 2008 and May 2009, which implied that soil acidification is not only related to the type of the soil but also the frequency and amount of acid precipitation.The two groups experiments, soil column continuous leaching experiments and the intermittent leaching experiments on potted plant by simulated acid rain are designed, for further research the change of Mt. Tai brown soil in different conditions of acidity gradient, as well as calcium and aluminum ions in the leachates. The results show that, the soil by pH2 acid rain is more significant in soil acidification status than the others, and there is no obvious difference in the three results of pH3,4,6. In soil column leaching experiment, soil acid buffering system has played a larger role, effectively inhibited lower soil pH in simulated acid rain pH3,4,6 treatments. On the contrary, the three datas increased within a small range. The accumulated loss of calcium is linear with the amount of leaching and aluminum ions is the exponential growth with the amount of leaching. There is a certain releasing rule between the amount of calcium and aluminum ions in the leachate. It is a linear positive correlation relationship between calcium and aluminum ions releasing in pH3,4,5 treatment, and in pH2 treatment condition, the releasing amount of aluminum ions increases exponentially with the increasing of calcium ions. In the leaching plant experiment, the process is always accompanied by releasing of aluminum ions, and in pH2 treatment condition, the soil acidification is obvious. However, plant growth is not impacted by short-term acid rain and even strong acid rain.