Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China; Guangxi Key Laboratory of Karst Ecological Processes and Services, Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang, 547100, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China.
Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China; Guangxi Industrial Technology Research Institute for Karst Rocky Desertification Control, Nanning, 530000, China.
J Environ Manage. 2024 Apr;356:120754. doi: 10.1016/j.jenvman.2024.120754. Epub 2024 Mar 23.
Afforestation on degraded croplands has been proposed as an effective measure to promote ecosystem functions including soil organic carbon (SOC) sequestration. Glomalin-related soil protein (GRSP) plays a crucial role in promoting the accumulation and stability of SOC. Nevertheless, mechanisms underlying the effects of afforestation on GRSP accumulation have not been well elucidated. In the present study, 14 pairs of maize fields and plantation forests were selected using a paired-site approach in a karst region of southwest China. By measuring soil GRSP and a variety of soil biotic and abiotic variables, the pattern of and controls on GRSP accumulation in response to afforestation were explored. The average content of total GRSP (T-GRSP) and its contribution to SOC in the maize field were 5.22 ± 0.29 mg g and 42.33 ± 2.25%, and those in the plantation forest were 6.59 ± 0.32 mg g and 25.77 ± 1.17%, respectively. T-GRSP content was increased by 26.4% on average, but its contribution to SOC was decreased by 39.1% following afforestation. T-GRSP content decreased as soil depth increased regardless of afforestation or not. Afforestation increased T-GRSP indirectly via its positive effects on arbuscular mycorrhizal fungi biomass, which was stimulated by afforestation through elevating fine root biomass or increasing the availability of labile C and N. The suppressed contribution of T-GRSP to SOC following afforestation was due to the relatively higher increase in other SOC components than T-GRSP and the significant increase of soil C:N ratio. Our study reveals the mechanisms underlying the effects of afforestation on T-GRSP accumulation, and is conducive to improving the mechanistic understanding of microbial control on SOC sequestration following afforestation.
在退化农田上造林被提议作为促进生态系统功能的有效措施，包括土壤有机碳（SOC）固存。球囊相关土壤蛋白（GRSP）在促进 SOC 的积累和稳定性方面起着至关重要的作用。然而，造林对 GRSP 积累的影响的机制尚未得到很好的阐明。本研究采用配对样点法，在中国西南喀斯特地区选择了 14 对玉米地和人工林。通过测量土壤 GRSP 以及各种土壤生物和非生物变量，探讨了 GRSP 积累对造林的响应模式及其控制因素。玉米地中总 GRSP（T-GRSP）及其对 SOC 的贡献率分别为 5.22±0.29mg/g 和 42.33±2.25%，人工林中分别为 6.59±0.32mg/g 和 25.77±1.17%。造林后，T-GRSP 含量平均增加了 26.4%，但其对 SOC 的贡献率却降低了 39.1%。无论是否造林，T-GRSP 含量均随土壤深度的增加而降低。造林通过增加菌根真菌生物量间接增加 T-GRSP，这是通过增加细根生物量或增加易降解 C 和 N 的可用性来刺激造林的。造林后 T-GRSP 对 SOC 的贡献受到抑制，这是由于其他 SOC 成分的相对增加量大于 T-GRSP，以及土壤 C:N 比的显著增加。本研究揭示了造林对 T-GRSP 积累的影响机制，有助于提高对造林后微生物控制 SOC 固存的机制理解。
