城市化对珠江三角洲存留常绿阔叶林土壤有机碳组分及其碳库管理指数的影响

通过对珠江三角洲城区(植物园、白云山、帽峰山)和郊区(鹤山、从化石门、鼎湖山)存留的6个常绿阔叶林进行调查,分析城市化对存留森林土壤有机碳组分和碳库管理指数的影响。在选择的样地按0—10,10—20cm分层采集土壤样品,并测定土壤总有机碳(TOC)、易氧化有机碳(ROC)和不易氧化有机碳(NROC)。结果表明:(1)城区森林土壤的TOC、ROC和NROC含量显著低于郊区(P0.05)。(2)在0—10cm层次,城区森林土壤碳库的活度和活度指数显著高于郊区(P0.05);在10—20cm,城区森林土壤碳库的活度和活度指数也高于郊区,但差异不显著。(3)在0—10,10—20cm,郊区森林土壤的碳库指数和碳库管理指数显著高于城市森林(P0.05)。城市化导致存留常绿阔叶林土壤有机碳活性增加,但不利于土壤总有机碳积累。

Effect of Urbanization on Soil Organic Carbon Fractions and Carbon Pool Management Index in Remnant Evergreen Broad-leaved Forests of the Pearl River Delta

In order to reveal effect of urbanization on soil organic carbon fractions and carbon pool management index,soil samples collected from six remnant evergreen broad-leaved forests in the Pearl River Delta were analyzed.The six sampling areas included three urban forests (botanical garden,Baiyunshan and Maofengshan) and three suburb ones (Heshan,Conghuashimen and Dinghushan).Soil samples were collected from 0-10 cm and 10-20 cm soil layers,respectively,and total organic carbon (TOC),readily oxidizable organic carbon (ROC) and non-readily oxidizable organic carbon (NROC) of the samples were determined.Results were as follows:(1) TOC,ROC and NROC content of urban forests soil was significantly lower than that of the suburban forests soil (P＜0.05).(2) In the surface soil (0-10 cm layer),soil carbon pool activity and carbon pool activity index of the urban forests were both significantly higher than those of the suburban forests (P＜0.05),and in the sub-surface soil (10-20 cm layer),the above pattern was also observed but there was no significant difference in both indices between these two kinds of forests (P＞0.05).(3) In both two soil layers,soil carbon pool index and carbon pool management index of suburban forests were both significantly higher than those of urban forests (P＜0.05).This study suggests that urbanization increased soil organic carbon activity of the remnant evergreen broad-leaved forests,but urbanization was detrimental to the accumulation of total organic carbon in soil.