摘要:探明亚热带山岳型国家公园不同林地利用方式下土壤呼吸（R_s）的动态变化规律以及影响因素，对准确评价和预测该区域以国家公园为主体的自然保护地体系的碳收支具有重要的现实意义。以武夷山国家公园为研究对象，利用Li-8100开路式土壤碳通量测定系统对茶园、锥栗（Castanea henryi（Skam） Rehd.et Wils.）林、马尾松（Pinus massoniana Lamb.）林和裸地的土壤呼吸及近地面气温、土壤温度、土壤湿度、土壤养分和土壤微生物碳（MBC）、氮（MBN）进行测定。结果显示：（1）与近地面气温、土壤温度和土壤湿度相同，不同林地的R_s均呈现夏 > 春 > 秋 > 冬的季节动态，R_s的季节均值按大小排序为茶园（3.10 μmol m^-2 s^-1） > 马尾松（2.96 μmol m^-2 s^-1） > 锥栗（2.32 μmol m^-2 s^-1） > 裸地（1.43 μmol m^-2 s^-1），锥栗和裸地之间、锥栗与马尾松之间均差异显著（P<0.01）。除马尾松林外，其他林地水热因子（近地面气温、土壤温度和土壤湿度）的单因子二次多项式模型对R_s的拟合度最高。水热因子共同建立的复合模型中，土壤温度、湿度的幂-指数模型对茶园R_s的拟合度较高，土壤温度和土壤湿度能够解释R_s变化的80%，马尾松林的R_s较适用于土壤温度、湿度建立的对数函数模型，而三因子线性模型（进入回归法）对锥栗林和裸地的R_s的拟合度最优，R²分别为0.565和0.281。（2）茶园和锥栗林的碳、氮、磷含量均高于马尾松林和裸地，MBN含量茶园 > 马尾松 > 锥栗 > 裸地。茶园的R_s与全磷（TP）、有效磷（AP）、全钾（TK）、速效钾（AK）含量呈极显著（P<0.01）正相关，马尾松林的R_s受TP、TK、AK含量的影响极显著（P<0.01），锥栗林的R_s与TK、AK、MBN含量呈现显著（P<0.05）正相关，裸地的R_s受MBN含量影响较为显著（P<0.05），4种林地土壤呼吸与养分的多元逐步回归方程R²均接近1。综上，茶园和马尾松林土壤呼吸速率较高，且所有林地的土壤呼吸均呈现夏 > 春 > 秋 > 冬的季节动态。温度和湿度与土壤呼吸的相关性强，是水热条件丰富的亚热带山岳地区土壤呼吸季节变化的主导因素，其中武夷山茶园土壤呼吸对水热因子的响应在4种林地中最为敏感。除温度和湿度外，各林地土壤呼吸受P、K元素的影响较大，其中茶园主要受P元素影响，马尾松林地受K元素影响较多。



Abstract:It is of practical significance for the accurate evaluation and prediction of the carbon budget of the natural reserve system in the region with national park as main body to explore the dynamic changes of soil respiration (R_s) and the influencing factors under different forest land use patterns in subtropical mountain-type national park. In Wuyishan National Park, the soil respiration, near surface temperature, soil temperature, soil moisture, soil nutrients, soil microbial carbon (MBC) and soil microbial nitrogen (MBN) of tea garden, Castanea henryi (skam) Rehd. et Wils. forest, Pinus massoniana Lamb. forest and bare land were measured by Li-8100 open circuit soil carbon flux measurement system. The results showed that:(1) Same as the near surface temperature, soil temperature and soil moisture, the R_s of different forest lands were ranked seasonally as summer > spring > autumn > winter, and the seasonal mean of the R_s was in the order of tea garden (3.10 μmol m^-2 s^-1) > P. massoniana (2.96 μmol m^-2 s^-1) > C. henryi (2.32 μmol m^-2 s^-1) > bare land (1.43 μmol m^-2 s^-1). There were extremely (P<0.01) significant differences between C. henryi forest and bare land, and between C. henryi forest and P. massoniana forest. Except for P. massoniana forest, the single-factor quadratic polynomial model of hydrothermal factors (near surface temperature, soil temperature and soil moisture) had the highest fitting degree to R_s. In the composite model jointly established by hydrothermal factors, the power-exponential model established of soil temperature and moisture had a high fitting degree to R_s of tea garden. Soil temperature and moisture can explain 80% of the change in R_s. The R_s of P. massoniana forest was suitable for the logarithmic function model established by soil temperature and moisture, and the three-factor linear model (Enter-regression method) had the best fit for R_s in C. henryi forest and bare land, with R² of 0.565 and 0.281, respectively. (2) The contents of the carbon, nitrogen, and phosphorus of tea garden and C. henryi forest were higher than those of P. massoniana forest and bare land. The order of MBN content was tea garden > P. massoniana > C. henryi > bare land. The difference was the biggest in summer, and the range was 59.47 mg/kg. There was an extremely (P<0.01) significant positive correlation between R_s and total phosphorus (TP), available phosphorus (AP), total potassium (TK) and available potassium (AK) content in tea garden. There was an extremely significant (P<0.01) positive correlation between R_s and TP, TK and AK content in P. massoniana forest. There was and a significant (P<0.05) positive correlation between R_s and TK, AK and MBN content in C. henryi forest. The R_s of bare land was significantly (P<0.05) affected by MBN content. The R² of multiple stepwise regression equations in four kinds of forest land are all close to 1. In summary, the soil respiration of tea garden and P. massoniana forest were higher, and the soil respiration of all forest land showed the seasonal dynamics of summer > spring > autumn > winter. The correlation between temperature and soil respiration, and the correlation between moisture and soil respiration were significant. Temperature and moisture were dominant factors in the seasonal change of soil respiration in subtropical mountain area with abundant hydrothermal conditions. Among them, the response of soil respiration to hydrothermal factors in tea garden of Wuyi Mountain was the most sensitive among four forest lands. In addition to temperature and moisture, the soil respiration of various forest lands was greatly affected by P and K elements, among which tea garden was mainly affected by P element, and that of P. massoniana forest was more affected by K element.





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