Centre for Forestry and Climate Change, Forest Research, Alice Holt Lodge, Farnham, Surrey GU10 4LH, UK.
Sci Total Environ. 2012 Apr 1;421-422:82-93. doi: 10.1016/j.scitotenv.2012.02.004. Epub 2012 Mar 3.
The dynamics of soil properties within a 70 year old oak plot were assessed every five years (1994-2009), by depth and by horizon to identify short term changes in soil carbon and nitrogen stocks, and acidity. The findings were set within a study of long term changes in soil properties in a 180 year chronosequence of oak plots from the same forest. Carbon stock increased significantly in the top mineral horizon - overall increase was 5 t C ha(-1), at a mean accumulation rate of 0.34 t C ha(-1)y(-1), which was mainly due to increase in horizon thickness. No increase was seen when soils were sampled by depth. Differences obtained by depth or horizon sampling due to changes in horizon thickness over time highlight the importance of horizon in the correct evaluation of soil property change in small scale sampling programs. This is particularly important in forest soils with high litter accumulation and low turnover rates when compared to other land uses. Nitrogen stock increases below 10cm soil depth were attributed to insect activity, litterfall variation and a change in water table. Findings were confirmed in the chronosequence study of oak across the forests; increases in soil C stocks of 0.1-0.2 t C ha(-1)y(-1) were calculated across young (25 years), mid-rotation (60 years) and old (120+ years) stands. Soil nitrogen increased significantly with canopy age whilst pH increased significantly between young-mid rotation stands but decreased between mid rotation and old stands. Significant increases in pH were also recorded before 2004 in the ECN 70 year old oak plots reflecting overall pollution recovery.
对 70 年生栎树样地的土壤性质每隔五年（1994-2009 年）进行了评估，从深度和层次两个方面来识别土壤碳氮储量和酸度的短期变化。该研究还设置了一个长期研究，即在同一森林中对 180 年栎树龄序列的土壤性质进行研究。在表层矿质土中，碳储量显著增加——总体增加了 5 t C ha(-1)，平均积累速率为 0.34 t C ha(-1)y(-1)，这主要是由于土层厚度的增加。当按深度采样时，并没有看到增加。由于土层厚度随时间的变化而导致的深度或层次采样差异突出了层次在小尺度采样方案中正确评估土壤性质变化的重要性。这在森林土壤中尤为重要，与其他土地利用相比，森林土壤具有高凋落物积累和低周转率的特点。10cm 以下土壤深度的氮储量增加归因于昆虫活动、凋落物变化和地下水位的变化。在森林栎树的年代序列研究中证实了这一发现；在年轻（约 25 年）、中龄（约 60 年）和老龄（120 年以上）林分中，土壤 C 储量分别增加了 0.1-0.2 t C ha(-1)y(-1)。土壤氮随着林冠年龄的增加而显著增加，而 pH 值在年轻-中龄林分之间显著增加，但在中龄和老龄林分之间则降低。在 2004 年之前，ECN 70 年生栎树样地的 pH 值也显著升高，反映出整体污染的恢复。
