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Scientia Silvae Sinicae ›› 2023, Vol. 59 ›› Issue (7): 45-53.doi: 10.11707/j.1001-7488.LYKX20220014

• Research papers • Previous Articles     Next Articles

Characteristics of Soil Carbon and Nitrogen Storage in Typical Communities of Natural Restoration and Succession of Vegetation in Karst Areas of Southwest China

Yuejin Zhang(),Qinyi Li,Haocai Wang,Weiyu Shi*   

  1. Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical Sciences, Southwest University Chongqing 400715
  • Received:2022-01-07 Online:2023-07-25 Published:2023-09-08
  • Contact: Weiyu Shi E-mail:1490957274@qq.com

Abstract:

Objective: This study is aimed to investigate the variation characteristics of soil carbon and nitrogen storage of typical communities in the process of vegetation natural restoration succession, and provide data support for vegetation restoration and reconstruction in southwest karst area. Method: By using the space-for-time substitution method, the natural restoration succession stages of abandoned cropland (abandoned cropland for half a year), grassland (5-10 a), shrub (15-25 a), shrub-forest (30-40 a) and forest (50-60 a) in karst trough valley of Zhongliang Mountain in Chongqing were selected as the research objects, permanent plots were established in each succession stages; the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3?-N), soil carbon-nitrogen ratio (C/N) and soil pH in 0-10, 10-30, 30-50, 50-70 cm were measured to estimate the soil carbon and nitrogen storage in each succession stage, and analyze the soil carbon and nitrogen content and storage characteristics in different stages of natural restoration succession. Result: The natural vegetation restoration and succession significantly increased SOC and TN contents and storage (P < 0.001), and the highest SOC and TN contents and storage were found in shrub-forest, with contents of 57.75 g·kg ?1 and 6.31 g·kg?1 and storage of 87.71 t·hm?2 and 10.06 t·hm?2, respectively, which increased by 51.88% and 30.31% compared with the abandoned farmland stage. The SOC storage in 0-30 cm soil layer accounted for 64.02%-73.68% of the 0-70 cm soil layer, and the soil TN storage accounted for 64.73%-78.55%. The soil C/N in 0-70 cm soil layer increased first and then decreased during the natural vegetation restoration succession, and the soil C/N in shrubland stage was the highest, which was 9.56. The C/N ratio of forest stage in 0-30 cm soil layer was the highest, which was 9.98, and the C/N ratio of 30-70 cm soil layer was relatively low. Soil NH4+-N storage of shrub-forest stage was the highest (0.103 t·hm?2), soil NO3?-N storage of abandoned farmland stage was the highest (0.076 t·hm?2), followed by shrub-forest stage (0.038 t·hm?2). The SOC and TN storage were significantly positively correlated with soil NH4+-N, NO3?-N and TP contents (P < 0.05), in addition, the SOC storage was also significantly positively correlated with soil TN and TK contents ( P < 0.05), and the soil TN storage was also significantly positively correlated with SOC contents ( P < 0.05). Soil C/N was positively correlated with SOC, TN, and NH 4+-N contents (P < 0.01), positively correlated with TP contents ( P < 0.05), and negatively correlated with TK contents ( P < 0.01). Conclusion: The succession of natural vegetation restoration in the karst area can significantly improve soil carbon and nitrogen content and storage (P < 0.001), and the effects on carbon and nitrogen content and storage and C/N in the 0-30 cm soil layer were more obvious than those in the 30-70 cm soil layer. There is a certain correlation between carbon and nitrogen storage and nutrient cycling. From the natural restoration succession of vegetation to the shrub-forest stage, soil carbon and nitrogen storage have been significantly increased to the peak ( P < 0.001); and the natural restoration of vegetation has a significant influence on the improvement of soil quality ( P < 0.001).

Key words: karst area, natural secondary forest, natural succession, carbon and nitrogen, content and storage

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