降水量变化下荒漠草原土壤呼吸及其影响因素  

Soil respiration and its influencing factors in a desert steppe in northwestern China under changing precipitation regimes

作　　者：李冰[1,2] 朱湾湾[3] 韩翠 余海龙 黄菊莹[2] LI Bing;ZHU Wan-Wan;HAN Cui;YU Hai-Long;HUANG Ju-Ying(School of Forestry and Prataculture,Ningxia University,Yinchuan 750021,China;Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwestern China,Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education,School of Ecology and Environment,Ningxia University,Yinchuan 750021,China;School of Geography and Planning,Ningxia University,Yinchuan750021,China)

机构地区：[1]宁夏大学林业与草业学院,银川750021 [2]西北土地退化与生态恢复国家重点实验室培育基地,西北退化生态系统恢复与重建教育部重点实验室,宁夏大学生态环境学院,银川750021 [3]宁夏大学地理科学与规划学院,银川750021

出　　处：《植物生态学报》2023年第9期1310-1321,共12页Chinese Journal of Plant Ecology

基　　金：宁夏自然科学基金(2022AAC02012和2022AAC03120);国家自然科学基金(32160277)。

摘　　要：土壤呼吸是陆地生态系统碳循环最关键的组分之一。研究降水量变化下荒漠草原土壤呼吸的时间动态及其与环境因子间的联系,可为深入理解降水格局改变下脆弱生态系统碳循环关键过程的调控机制提供数据支撑。该研究基于2014年在宁夏荒漠草原设立的降水量变化(减少50%、减少30%、自然、增加30%、增加50%)的野外控制实验,探究了2019年6–10月土壤呼吸速率的时间动态,分析了土壤呼吸速率与土壤性质和植物特征的关系。整个生长季土壤呼吸速率呈先增加后减弱的时间动态,最大值(2.79–5.35μmol·m^(–2)·s^(–1))出现在7月下旬或8月上旬。与自然降水量相比,减少30%降水量对土壤呼吸速率无显著影响,反映了土壤呼吸对适度干旱的适应性。整体来看,减少50%降水量降低了土壤呼吸速率,增加降水量(尤其是增加30%)提高了土壤呼吸速率,且其促进作用在前期(6–7月)尤为明显。土壤呼吸速率与土壤温度呈显著的指数关系,与土壤含水量呈显著的线性关系。土壤理化性质对土壤呼吸速率有高的独立解释力,且其影响与土壤生物学性质和植物多样性高度相关。降水量可直接影响土壤呼吸速率,也可通过影响土壤生物学性质和植物生物量间接影响土壤呼吸速率。该研究结果表明,适度增加降水量缓解了荒漠草原土壤水分受限性、刺激了土壤酶活性、促进了微生物活性和植物生长,从而加速了土壤呼吸;极端增加降水量则可能导致土壤透气性降低、微生物代谢活动受阻,进而抑制土壤呼吸。Aims Soil respiration is one of the most critical components of carbon cycle in terrestrial ecosystems.The study on temporal dynamics of soil respiration and its linkage with environmental factors in desert steppes under changing precipitation can provide data supports for a deep understanding of the regulatory mechanisms of key carbon cycling processes in fragile ecosystems.Methods A field experiment involving five precipitation treatments(50%reduction,30%reduction,natural,30%increase,50%increase)was set up in 2014 in a desert steppe in Ningxia.The temporal dynamics of soil respiration rate were explored during the growing season(from June to October)in 2019,and the relationships between soil respiration rate and soil properties and plant characteristics were analyzed.Important findingss Soil respiration rate showed a seasonal variation of an increasing and a decreasing trend across the growing season,with the maximum values(2.79-5.35μmol·m^(2).s^(-1))occurring in late July or early August.Compared with the natural condition,30%reduction in precipitation did not result in a significant effect on soil respiration rate,reflecting the adaptability of soil respiration to moderate drought.Overall,50%reduction in precipitation reduced soil respiration rate,whereas increased precipitation(especially the 30%increase)enhanced soil respiration rate,and this positive effect was especially obvious in the early growing season(June to July).Soil respiration rate had a significantly exponential relationship with soil temperature and a significantly linear relationship with soil water content.Soil physicochemical property had a highly independent explanatory power for soil respiration rate(R^(2)=0.36),and its effect was highly correlated with soil biological property and plant diversity(R^(2)=0.31).Precipitation could affect soil respiration rate either directly or indirectly through the influences on soil biological property and plant biomass.The results indicated that a moderate increase in precipitation could accelerate so

关 键 词：降水格局改变 荒漠草原 植物群落特征 土壤碳源 土壤性质 

分 类 号：S812.2[农业科学—草业科学]