Li Qingxue, Jia Zhiqing, He Lingxianzi, Zhao Xuebin, Yang Henghua
Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing, China.
Qinghai Gonghe Desert Ecosystem Research Station, China Terrestrial Ecosystem Research Network, Qinghai, China.
Front Plant Sci. 2023 Mar 9;14:1093678. doi: 10.3389/fpls.2023.1093678. eCollection 2023.
Shrubs are the main species in desert ecosystems. Better understanding shrubs fine root dynamics and its contribution to soil organic carbon (SOC) stocks can improve the accuracy of carbon sequestration estimation and provide basic data for the calculation of carbon sequestration potential. The ingrowth core method was used to investigate the fine root (< 1 mm in diameter) dynamics of Kuang et H. C. Fu plantation with different age (4-, 6-, 11-, 17-, and 31-year-old) in Gonghe Basin of the Tibetan Plateau, and the annual fine root mortality was used for calculation the annual carbon input to SOC pool. The results showed that fine root biomass, production, and mortality first increased and then decreased as the plantation age increased. Fine root biomass peaked in 17-year-old plantation, production and mortality peaked in 6-year-old plantation, and turnover rate of 4- and 6-year-old plantations were significantly higher than other plantations. Fine root production and mortality were negative correlated with soil nutrients at depth of 0-20 and 20-40 cm. The variation range of carbon input by fine root mortality across different plantation age at 0-60 cm soil depth was 0.54-0.85 Mg ha year, accounting for 2.40-7.54% of the SOC stocks. plantation has a strong carbon sequestration potential from long time scale. Fine roots regenerate faster in young stands and lower soil nutrients environment. Our results suggest that the influences of plantation age and soil depth should be taken into account when calculating the contribution of fine root to SOC stocks in desert ecosystems.
灌木是沙漠生态系统中的主要物种。更好地了解灌木细根动态及其对土壤有机碳（SOC）储量的贡献，可以提高碳固存估算的准确性，并为碳固存潜力的计算提供基础数据。采用根生长袋法研究了青藏高原共和盆地不同年龄（4年、6年、11年、17年和31年）的匡氏梭梭和黑果枸杞人工林细根（直径<1毫米）动态，并利用细根年死亡率计算了SOC库的年碳输入量。结果表明，随着人工林年龄的增加，细根生物量、生产量和死亡率先增加后降低。细根生物量在17年生人工林中达到峰值，生产量和死亡率在6年生人工林中达到峰值，4年生和6年生人工林的周转率显著高于其他人工林。在0-20厘米和20-40厘米深度处，细根生产量和死亡率与土壤养分呈负相关。在0-60厘米土壤深度范围内，不同年龄人工林细根死亡碳输入量的变化范围为0.54-0.85 Mg ha-1 year-1，占SOC储量的2.40-7.54%。从长期来看，人工林具有很强的碳固存潜力。幼龄林和低土壤养分环境下细根再生更快。我们的研究结果表明，在计算沙漠生态系统中细根对SOC储量的贡献时，应考虑人工林年龄和土壤深度的影响。
