Zhao Xinyu, Liu Peiling, Feng Yingjie, Zhang Weiqiang, Njoroge Brian, Long Fengling, Zhou Qing, Qu Chao, Gan Xianhua, Liu Xiaodong
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China.
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
Front Plant Sci. 2022 Jun 3;13:878908. doi: 10.3389/fpls.2022.878908. eCollection 2022.
Vegetation succession can change the function and quality of the soil. Exploring the changes in soil properties during secondary forest restoration is of great significance to promote forest restoration and improve the ecological service function of subtropical ecosystems in South China. In this study, we chose three typical forests in subtropical China as restoration sequences, broadleaf-conifer mixed forest (EF), broad-leaved forest (MF), and old-growth forest (LF), to study the changes in soil physico-chemical and biological properties and the changes of soil comprehensive quality during the secondary succession of subtropical forest. The results showed that the soil physical structure was optimized with the progress of forest succession. The soil bulk density decreased gradually with the progress of forest restoration, which was significantly affected by soil organic carbon ( < 0.01). In LF, the soil moisture increased significantly ( < 0.05), and its value can reach 47.85 ± 1.93%, which is consistent with the change of soil porosity. With the recovery process, soil nutrients gradually accumulated. Except for total phosphorus (TP), there was obvious surface enrichment of soil nutrients. Soil organic carbon (15.43 ± 2.28 g/kg), total nitrogen (1.08 ± 0.12 g/kg), and total phosphorus (0.43 ± 0.03 g/kg) in LF were significantly higher than those in EF ( < 0.05). The soil available nutrients, that is, soil available phosphorus and available potassium decreased significantly in LF ( < 0.05). In LF, more canopy interception weakened the P limitation caused by atmospheric acid deposition, so that the soil C:P (37.68 ± 4.76) and N:P (2.49 ± 0.24) in LF were significantly lower than those in EF ( < 0.05). Affected by TP and moisture, microbial biomass C and microbial biomass N increased significantly in LF, and the mean values were 830.34 ± 30.34 mg/kg and 46.60 ± 2.27 mg/kg, respectively. Further analysis showed that total soil porosity (TSP) and TP (weighted value of 0.61) contributed the most to the final soil quality index (SQI). With the forest restoration, the SQI gradually increased, especially in LF the value of SQI was up to 0.84, which was significantly higher than that in EF and MF ( < 0.05). This result is of great significance to understanding the process of restoration of subtropical forests and improving the management scheme of subtropical secondary forests.
植被演替会改变土壤的功能和质量。探究次生林恢复过程中土壤性质的变化对于促进森林恢复以及提升中国南方亚热带生态系统的生态服务功能具有重要意义。在本研究中，我们选取了中国亚热带地区的三种典型森林作为恢复序列，即针阔混交林（EF）、阔叶林（MF）和老龄林（LF），来研究亚热带森林次生演替过程中土壤理化性质和生物学性质的变化以及土壤综合质量的变化。结果表明，随着森林演替的推进，土壤物理结构得到优化。土壤容重随着森林恢复进程逐渐降低，这受到土壤有机碳的显著影响（<0.01）。在老龄林中，土壤湿度显著增加（<0.05），其值可达47.85±1.93%，这与土壤孔隙度的变化一致。随着恢复过程推进，土壤养分逐渐积累。除全磷（TP）外，土壤养分存在明显的表聚现象。老龄林中的土壤有机碳（15.43±2.28克/千克）、全氮（1.08±0.12克/千克）和全磷（0.43±0.03克/千克）显著高于针阔混交林（<0.05）。老龄林中土壤有效养分，即土壤有效磷和速效钾显著降低（<0.05）。在老龄林中，更多的林冠截留减弱了大气酸沉降造成的磷限制，使得老龄林中的土壤碳磷比（37.68±4.76）和氮磷比（2.49±0.24）显著低于针阔混交林（<0.05）。受全磷和湿度影响，老龄林中微生物生物量碳和微生物生物量氮显著增加，平均值分别为830.34±30.34毫克/千克和46.60±2.27毫克/千克。进一步分析表明，土壤总孔隙度（TSP）和全磷（加权值为0.61）对最终土壤质量指数（SQI）的贡献最大。随着森林恢复，土壤质量指数逐渐增加，尤其是在老龄林中土壤质量指数高达0.84，显著高于针阔混交林和阔叶林（<0.05）。这一结果对于理解亚热带森林恢复过程以及改进亚热带次生林经营方案具有重要意义。
