State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.
J Environ Manage. 2024 Sep;367:122005. doi: 10.1016/j.jenvman.2024.122005. Epub 2024 Jul 30.
Soil organic carbon and nitrogen play pivotal roles as indicators of soil quality and ecological functioning in wetlands. The escalating impact of human activities and climate change has led to a severe degradation of wetland soils, particularly in semi-arid regions. However, an understanding of the factors governing the dynamics of total soil organic carbon (TSOC) and total soil nitrogen (TSN) in semi-arid areas remains elusive, impeding a comprehensive understanding of wetland ecological functions. The present study investigated variations in TSOC and TSN content as well as vegetation and soil physicochemical properties under five different land management practices (mowed wetlands, mowed and slightly grazed wetlands, moderately grazed wetlands, heavily grazed wetlands, and natural wetlands unaffected by human interference) in the semi-arid Songnen Plain region of China. The results revealed significant decreases in TSOC and TSN content within managed wetlands compared to natural wetlands. Moreover, positive correlations were observed between pairs of SOC-TN or their storage values for SOC (TSOC)-TN (TSN). Furthermore, TSOC and TSN exhibited significant positive associations with aboveground and belowground biomass levels, stem C:N, stem C:P, soil C:P, and soil N:P. Additionally, redundancy analysis indicated that species diversity accounted for 37.4% of the variations in TSOC-TSN while belowground biomass accounted for 8.5% of the variations. Furthermore, nutrient content within stems (particularly N content and C:P) contributed to a 37.2% variation in TSOC and TSN whereas root nutrient content (especially N:P, C:N, and C:P) contributed to a 15.3% variation. Soil C:P, C:N, and total phosphorous (TP) content accounted for 65.7%, 9.6%, and 7.5% of variations of TSOC and TSN, respectively. Besides, variation partitioning analysis revealed that plant community characteristics, community nutrient content, and soil physicochemical properties collectively influenced the dynamics of TSOC and TSN. Among these factors, soil physicochemical properties emerged as the primary drivers of carbon and nitrogen dynamics in degraded wetlands in semi-arid regions. The impact on TSN was more pronounced than that of TSOC. This study provides valuable insights for understanding the processes and mechanisms underlying carbon and nitrogen accumulation in degraded wetlands, facilitating the development of regionally adaptive management plans under different management practices.
土壤有机碳和氮作为湿地土壤质量和生态功能的指标起着至关重要的作用。人类活动和气候变化的影响不断加剧，导致湿地土壤严重退化，特别是在半干旱地区。然而，对于控制半干旱地区土壤总有机碳（TSOC）和总土壤氮（TSN）动态的因素仍缺乏了解，这阻碍了对湿地生态功能的全面理解。本研究调查了在中国半干旱的松嫩平原地区，五种不同土地管理措施（割草湿地、割草和轻度放牧湿地、中度放牧湿地、重度放牧湿地和不受人类干扰的自然湿地）下的 TSOC 和 TSN 含量以及植被和土壤理化性质的变化。结果表明，与自然湿地相比，管理湿地的 TSOC 和 TSN 含量显著降低。此外，SOC-TN 或 SOC（TSOC）-TN（TSN）的储存值之间存在正相关关系。此外，TSOC 和 TSN 与地上和地下生物量水平、茎 C:N、茎 C:P、土壤 C:P 和土壤 N:P 呈显著正相关。此外，冗余分析表明，物种多样性解释了 TSOC-TSN 变化的 37.4%，而地下生物量解释了 8.5%的变化。此外，茎内养分含量（特别是 N 含量和 C:P）对 TSOC 和 TSN 的变化贡献了 37.2%，而根养分含量（特别是 N:P、C:N 和 C:P）对 TSOC 和 TSN 的变化贡献了 15.3%。土壤 C:P、C:N 和总磷（TP）含量分别占 TSOC 和 TSN 变化的 65.7%、9.6%和 7.5%。此外，变异分解分析表明，植物群落特征、群落养分含量和土壤理化性质共同影响了 TSOC 和 TSN 的动态变化。在这些因素中，土壤理化性质是半干旱退化湿地中碳和氮动态变化的主要驱动因素。对 TSN 的影响比 TSOC 更显著。本研究为理解退化湿地中碳和氮积累的过程和机制提供了有价值的见解，为不同管理措施下制定区域适应性管理计划提供了依据。
