Yao Xiong, Yu Kunyong, Wang Guangyu, Deng Yangbo, Lai Zhuangjie, Chen Yan, Jiang Yusen, Liu Jian
College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; University Key Lab for Geomatics Technology and Optimize Resources Utilization in Fujian Province, Fuzhou, Fujian 350002, China.
Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Sci Total Environ. 2019 Sep 15;683:98-108. doi: 10.1016/j.scitotenv.2019.05.221. Epub 2019 May 20.
Soil erosion and reforestation greatly affects the functionality of many terrestrial ecosystems. However, the effects of soil erosion and reforestation on soil respiration (SR), and soil organic carbon (SOC) and total nitrogen (TN) stocks remain unclear. Therefore, we investigated the changes in SR, and SOC and TN stocks at four different soil erosion levels (severely, moderately, lightly, and non-eroded) and two different aged Pinus massoniana plantations (8- and 36-year-old) in the hilly red soil regions of Southern China. Our results showed that soil erosion level and reforestation significantly influenced SR, and SOC and TN stocks. Meanwhile, the mean SR, and SOC and TN stocks all significantly decreased with erosion level but increased significantly with times since reforestation. Soil temperature (ST) could explain 70-92% of SR seasonal variation based on exponential models, whereas no significant relationship between SR and soil water content were found. Furthermore, the structural equation modeling indicated that SOC stocks at 0-20 cm had a much stronger effect on SR than ST. Meanwhile, the SOC stocks for 0-20 cm increased by 177% and 558% in the 8- and 36-year-old Pinus massoniana plantations in comparison with the severely eroded forestland, respectively. This study highlights that reforestation could be an effective strategy for restoring the carbon and nitrogen storage in eroded regions of Southern China and emphasizes the need to consider the effects of soil erosion and reforestation when assessing regional carbon budgets under different climate scenarios.
土壤侵蚀和重新造林对许多陆地生态系统的功能有很大影响。然而，土壤侵蚀和重新造林对土壤呼吸（SR）、土壤有机碳（SOC）和全氮（TN）储量的影响仍不明确。因此，我们在中国南方丘陵红壤地区调查了四个不同土壤侵蚀水平（严重、中度、轻度和未侵蚀）和两个不同树龄（8年和36年）的马尾松人工林中SR、SOC和TN储量的变化。我们的结果表明，土壤侵蚀水平和重新造林显著影响SR、SOC和TN储量。同时，平均SR、SOC和TN储量均随侵蚀水平显著降低，但随重新造林后的时间显著增加。基于指数模型，土壤温度（ST）可以解释SR季节变化的70%-92%，而未发现SR与土壤含水量之间存在显著关系。此外，结构方程模型表明，0-20厘米深度的SOC储量对SR的影响比ST强得多。同时，与严重侵蚀的林地相比，8年和36年树龄的马尾松人工林中0-20厘米深度的SOC储量分别增加了177%和558%。本研究强调，重新造林可能是恢复中国南方侵蚀地区碳氮储量的有效策略，并强调在评估不同气候情景下的区域碳预算时，需要考虑土壤侵蚀和重新造林的影响。
