水位和增温对崇明东滩滨海围垦湿地土壤呼吸的影响
发布时间：2019-05-21 14:11
【摘要】：湿地水文控制和维持湿地生态系统的结构和功能,水文状态的改变必然会对土壤呼吸速率产生影响。全球气温升高对湿地生态系统的碳循环也会产生影响。因此,有必要研究水位和增温对湿地土壤呼吸的影响及其影响机制。本文以上海市崇明东滩滨海围垦湿地为研究对象,于2014年4月到10月,测定了不同水位梯度以及增温和不增温处理下的土壤呼吸(RST)、根呼吸(RSR)、无根土壤呼吸(RSS)和表层凋落物呼吸(RSL),并测定了土壤温湿度、理化性质以及生物因子,研究了水位和增温对土壤呼吸及其组分的影响,并探讨了水位和增温对土壤呼吸的影响机制,以期为预测该地区在不同水位调控以及增温背景下的湿地固碳能力提供参考,并为湿地的科学管理提供基础数据和依据。研究结果表明：1、水位对土壤呼吸及其组分的影响(1)不同水位梯度下,土壤呼吸及其组分日动态呈单峰曲线,表现为中水位低水位高水位,最大值出现在12：00-14：00,最小值出现在00：00-03：00。土壤呼吸及其组分季节变化明显,除RSL呈单峰曲线外,其它组分及RST都呈多峰曲线。生长季低、中、高水位土壤总呼吸平均值分别为3.14、3.48、2.16,低水位显著大于高水位,但比中水位小,证明随着水位降低,土壤呼吸并非一直增大,而是水位下降超过一定阈值后,土壤呼吸会再度受到抑制。(2)不同水位梯度下,土壤呼吸及其组分日动态与土壤5cm温度均具有显著指数关系(P0.05),土壤体积含水量与土壤呼吸相关性不显著(P0.05)。整个生长季,土壤呼吸及其组分季节动态与土壤温度无显著关系。地面无积水时,不同水位梯度下RST与土壤温度均具有显著指数关系(P0.05),各组分中只有RSR与土壤温度具有显著指数关系(P0.05),土壤温度可以解释RST和RSR季节变化的51.9%-68.8%和46.9%-58.3%；地面积水时,土壤呼吸及其组分与土壤温度无显著相关性(P0.05)。(3)不同水位梯度下,土壤呼吸各组分贡献率大小顺序均为：RSRRSS RSL,且三者之间差异显著(P0.05),但水位梯度对三者贡献率无显著影响(P0.05)。(4)低、中、高水位RST的Q10值分别为1.51、2.51、1.63,RSR的Q10值分别是1.70、3.73、1.85,表明中水位的土壤总呼吸和根呼吸的温度敏感性最强,且根呼吸温度敏感性强于土壤总呼吸。2、增温对土壤呼吸及其组分的影响(1)在季节尺度上,OTC升温效果明显,空气温度平均增加了1.61±0.16℃(P0.01),土壤5cm温度平均升高了1.09±0.15℃(P0.01)。在日尺度上,增温效果只出现在白天,OTC内夜间土壤温度比CK低。(2)CK和OTC的土壤呼吸及其组分日动态均呈单峰曲线,峰值出现时间基本一致。总体上而言,增温处理日均呼吸速率大于对照(P0.05)。两种处理条件下土壤呼吸及其组分均具有明显的季节变化,除RSL呈单峰曲线外,其它组分及RST都呈多峰曲线。生长季OTC显著促进了RST、RSR、RSS(P0.05)。(3)两种处理下,土壤呼吸及其组分日动态与土壤5cm温度均具有显著指数关系(P0.05),整个生长季土壤呼吸及其组分季节动态与土壤温度无显著关系(P0.05)。地面无积水时,增温处理RST、RSR、RSS与土壤温度均具有显著指数关系(P0.05),对照处理RST和RSR与土壤温度具有显著指数关系(P0.05)；地面积水时,土壤呼吸及其组分与土壤温度均无显著相关性(P0.05)。(4)增温和对照处理下,土壤呼吸各组分贡献率大小顺序均为：RSRRSSRSL,且三者之间差异显著(P0.05),但增温对各组分贡献率无显著影响(P0.05)。(5)OTC处理下RST、RSR、RSS的Q10值分别为2.86、3.25、2.61,CK处理下RST和RSR的Q10值分别为2.51和3.73,表明增温提升了土壤总呼吸的温度敏感性,同时削弱了根呼吸的温度敏感性；根呼吸温度敏感性强于土壤总呼吸。
[Abstract]:The hydrological control of the wetland and the structure and function of the wetland ecosystem will have an effect on the respiration rate of the soil. The global temperature rise will also have an impact on the carbon cycle of the wetland ecosystem. Therefore, it is necessary to study the effect of water level and temperature increase on the respiration of wetland soil and its influencing mechanism. Soil respiration (RST), root respiration (RSR), non-root soil respiration (RSS) and surface litter respiration (RSL) under different water level gradients and temperature and non-warming treatments were measured in the coastal reclamation wetland of Dongtan, Chongming, Shanghai, from April to October,2014. The effects of water level and temperature on the respiration of soil and its components were studied and the effects of water level and temperature on the respiration of soil were discussed. So as to provide reference for predicting the carbon sequestration capacity of the wetland under different water level regulation and temperature increasing background, and provide the basic data and the basis for the scientific management of the wetland. The results show that:1. The effect of water level on the respiration of soil and its components (1) The soil respiration and its composition day have a unimodal curve under different water level gradients. The results show that the maximum water level and the maximum value of the medium water level are in the range of 12:00-14:00, and the minimum value is at 00:00-03:00. In addition to the unimodal curve of RSL, the other components and the RST showed a multi-modal curve. The average respiration average of the middle and high water-level soil is 3.14, 3.48, 2.16, and the low water level is significantly higher than that of the high water level, but the water level is small, and the soil respiration is not always increased with the decrease of the water level, but the soil respiration will be inhibited again after the water level drops more than a certain threshold. (2) Under different water-level gradients, the soil respiration and its composition date had a significant exponential relationship with the soil's 5 cm temperature (P0.05), and the soil volume water content was not significant with the soil respiration (P0.05). There was no significant relationship between the soil respiration and the soil temperature during the whole growing season. There was a significant exponential relationship between the RSR and the soil temperature in different water-level gradients (P0.05). The soil temperature could explain the 51.9%-68.8% and 46.9%-58.3% of the changes in the RST and RSR seasons. There was no significant correlation between the soil respiration and its components and soil temperature (P0.05). (3) The rate of contribution of each component in the soil respiration was: RSRRSS RSL, and the difference between the three levels was significant (P0.05), but the water level gradient had no significant effect on the contribution rate of the three components (P0.05). (4) The Q10 value of the low, medium and high water level RST is 1.51, 2.51, 1.63, and the Q10 value of the RSR is 1.70, 3.73, 1.85, respectively. The effect of increasing the temperature on the respiration and the components of the soil (1) on the seasonal scale was obvious, the air temperature increased by 1.61-0.16 鈩，
本文编号：2482151
[Abstract]:The hydrological control of the wetland and the structure and function of the wetland ecosystem will have an effect on the respiration rate of the soil. The global temperature rise will also have an impact on the carbon cycle of the wetland ecosystem. Therefore, it is necessary to study the effect of water level and temperature increase on the respiration of wetland soil and its influencing mechanism. Soil respiration (RST), root respiration (RSR), non-root soil respiration (RSS) and surface litter respiration (RSL) under different water level gradients and temperature and non-warming treatments were measured in the coastal reclamation wetland of Dongtan, Chongming, Shanghai, from April to October,2014. The effects of water level and temperature on the respiration of soil and its components were studied and the effects of water level and temperature on the respiration of soil were discussed. So as to provide reference for predicting the carbon sequestration capacity of the wetland under different water level regulation and temperature increasing background, and provide the basic data and the basis for the scientific management of the wetland. The results show that:1. The effect of water level on the respiration of soil and its components (1) The soil respiration and its composition day have a unimodal curve under different water level gradients. The results show that the maximum water level and the maximum value of the medium water level are in the range of 12:00-14:00, and the minimum value is at 00:00-03:00. In addition to the unimodal curve of RSL, the other components and the RST showed a multi-modal curve. The average respiration average of the middle and high water-level soil is 3.14, 3.48, 2.16, and the low water level is significantly higher than that of the high water level, but the water level is small, and the soil respiration is not always increased with the decrease of the water level, but the soil respiration will be inhibited again after the water level drops more than a certain threshold. (2) Under different water-level gradients, the soil respiration and its composition date had a significant exponential relationship with the soil's 5 cm temperature (P0.05), and the soil volume water content was not significant with the soil respiration (P0.05). There was no significant relationship between the soil respiration and the soil temperature during the whole growing season. There was a significant exponential relationship between the RSR and the soil temperature in different water-level gradients (P0.05). The soil temperature could explain the 51.9%-68.8% and 46.9%-58.3% of the changes in the RST and RSR seasons. There was no significant correlation between the soil respiration and its components and soil temperature (P0.05). (3) The rate of contribution of each component in the soil respiration was: RSRRSS RSL, and the difference between the three levels was significant (P0.05), but the water level gradient had no significant effect on the contribution rate of the three components (P0.05). (4) The Q10 value of the low, medium and high water level RST is 1.51, 2.51, 1.63, and the Q10 value of the RSR is 1.70, 3.73, 1.85, respectively. The effect of increasing the temperature on the respiration and the components of the soil (1) on the seasonal scale was obvious, the air temperature increased by 1.61-0.16 鈩，
本文编号：2482151
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