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题名	干旱荒漠区不同生态系统土壤CO2释放通量研究
作者	张丽华
学位类别	博士
答辩日期	2009
授予单位	中国科学院．新疆生态与地理研究所
授予地点	北京
导师	陈亚宁，中国科学院新疆生态与地理研究所
关键词	碳循环
其他题名	Analysis on soil CO2 efflux under different ecosystems in arid region
学位专业	自然地理学
中文摘要	新疆在大规模农业开发的同时，也在大力营造防护林。荒漠上植树造林后，土壤呼吸强度和时间格局将发生改变。揭示干旱区荒漠、人工林地土壤呼吸的基本规律和影响因素，评估不同土地利用/覆盖类型的土壤呼吸对温度变化响应的敏感度，将为进一步确定干旱荒漠区不同生态系统的CO2源/汇关系、揭开全球未知汇之谜奠定基础并提供依据。本文以准噶尔盆地西部克拉玛依农业综合开发区主干防护林杨树、榆树林地和封育荒漠——梭梭、假木贼、盐穗木、柽柳＋芦苇群落为研究对象，通过对土壤呼吸、温度、土壤含水量、土壤养分、盐分监测与调查，研究了不同植被覆盖类型土壤呼吸速率的时间变化规律，定量分析了生物、非生物因子对土壤呼吸的影响；通过模拟降水实验探讨了土壤CO2释放对降水激发的响应过程与原理；并利用指数模型估算了生长季人工林地、荒漠土壤碳释放量。 数据分析表明，生长季荒漠土壤呼吸速率日变化呈现明显的单峰格局，与地表温度具有较高一致性；而人工林土壤呼吸日波动明显，与近地面气温、上层土壤温度(5－20cm)的变化具有较高相关性。荒漠、人工林土壤呼吸季节变化均呈单峰型，6、7月达到峰值；荒漠与气温变化基本一致，夏季温度最高时因土壤水分降低土壤呼吸出现下降，人工林与土壤温度变化一致。 近地面气温对梭梭、假木贼、盐穗木、柽柳＋芦苇荒漠群落土壤呼吸季节变化的解释率最高，分别达到36.9％、50.7％、64.5％、69.7％，Q10值分别为1.35、1.41、1.52和1.45；50cm、35cm土壤温度对杨树、榆树林地土壤呼吸季节变化的解释率最高，分别达到78.5％、64.4％，Q10值分别为2.89、2.32。不同植被覆盖类型土壤呼吸受土壤含水量的影响程度不同。消除温度的混淆影响后，梭梭、假木贼、盐穗木群落土壤呼吸与土壤含水量均具有显著正相关(R2=0.55、0.58、0.48)，柽柳＋芦苇群落仅2006年土壤呼吸与土壤含水量具有显著负相关；在人工林地两者之间没有显著关系。温度、土壤含水量对典型荒漠土壤呼吸的协同影响较单因素提高，分别为梭梭(71-93%)、假木贼(79-82%)、盐穗木群落(70-80%)；在柽柳+芦苇群落和人工林地，影响差别不明显。 土壤理化性质对荒漠群落土壤呼吸具有一定影响。4种荒漠土壤基础呼吸速率(10℃时)与土壤有机质、有机碳、有效N呈显著正相关，与全P呈显著负相关。高、低盖度的梭梭、假木贼、盐穗木群落土壤呼吸与土壤速效K、pH值、HCO3-离子具有显著正相关，与SO42-离子呈显著负相关。土壤容重未引起群落间土壤呼吸速率的差异。 不同土地利用/覆盖类型，由于植被、经营方式、土壤性质及小气候等差异，土壤呼吸日变化格局不同，土壤呼吸速率差异显著(杨树林地＞柽柳＋芦苇群落＞梭梭群落)，土壤呼吸对温度的响应不同。仅高盖度梭梭群落与其他样地间土壤呼吸存在显著差异。各样地土壤呼吸速率时间变化对温度的响应程度不同(22－74％)，仅在高盖度梭梭(土壤湿度最低)、盐穗木样地(土壤湿度最高)土壤呼吸与土壤含水量间存在显著负相关性。杨树林地土壤呼吸速率显著高于榆树林地，林内温度、土壤含水量、土壤养分和盐分性质并未存在明显差异，林地生长状况、光合作用是两种林地间土壤呼吸差异的主要原因。 模拟降水对荒漠土壤呼吸速率起到激发作用，但未发生短时间内较大的脉冲式增加。假木贼、盐穗木荒漠10mm模拟降水后土壤CO2累积释放量大于20mm；假木贼群落以5mm大于2.5mm，盐穗木以2.5mm更高。综合分析，荒漠土壤累积CO2释放量随降水量增加显著下降。 生长季人工林地土壤碳释放量高于荒漠群落，杨树林地高于榆树林地，荒漠中物种多样性更高、盖度更大的柽柳＋芦苇群落高于3种典型荒漠，其中小乔木梭梭群落高于假木贼、盐穗木群落，分别为653.33、301.85、217.38、119.19、85.11、69.08 gC m2-。With large-scale agricultural development, a great deal of shelterbelt has been built. As reforestation on the desert, soil respiration rate and pattern will also change. To reveal the basic law of soil respiration and impact factors and to estimate the temperature sensitivity of soil respiration at different land use/cover types, will provide a basis for evaluation on sources and sinks of CO2 in desert ecosystem and missing sink. In this paper, taken two kinds of artificial shelterbelts and four kinds of desert communities as the research objective, based on monitor of soil respiration, temperature, soil water content, soil nutrients and salinity, analyze the temporal variation of soil respiration rate under different ecosystems, quantitatively examine the influence of biological and non-biological factors on soil respiration, explore the process and principle of stimulated CO2 release from soil through the simulated precipitation experiments, and estimate the soil CO2 efflux in growing season under defferent ecosystems. The results showed that the soil respiration in deserts appeared single-peaked daytime change, consistently with air temperature and soil surface temperature; while soil respiration fluctuated markedly at artificial shelterbelts, which was correlated with air temperature near soil surface and soil temperature at 5-20cm depth. The soil respiration experienced single-peaked (June or July) seasonal trend at deserts and shelterbelts. The response of soil respiration to air temperature near soil surface were strongest, the R2 and Q10 values were 0.369 and 1.35 at H. ammodendron, 0.507 and 1.41 at A. aphylla, 0.645 and 1.52 at H. caspica, 0.697 and 1.45 at T. ramosissima+ Ph.Communis community. The correlation between soil respiration and soil temperature at 50cm and 35cm was highest at Populus and Ulmus pumila woodland, and the R2 and Q10 values were 0.785 and 2.886, 0.644 and 2.316, respectively. After eliminating the confusing effect of temperature there were positive correlation between soil respiration and soil water content at H. ammodendron, A. aphylla and H. caspica communities, significant and negative correlation existed at T. ramosissima+ Ph. Communis community in 2006, and insignificant correlation was at artificial shelterbelts. Soil nutrients and salinities influence soil respiration in some extent. The base soil respiration at 10℃ was positively correlated with soil organic matter, soil organic carbon and available N, negatively correlated with total P among four desert communities. Soil bulk dendity was not the principle reason for difference in soil respiration among desert communities. The difference in soil respiration rate was significant among different vegetation types (Populus woodland﹥T. ramosissima+ Ph. Communis﹥H. ammodendron community), and the response of soil respiration to air temperature and soil temperature was also different among them. The difference in soil respiration between high coverage (50%) site at H. ammodendron community and low coverage sites (lower than 25%) at other communities was significant. Soil respiration was higher significantly at Populus woodland than that at U. pumila woodland, photosynthesis difference was one of the reasons. Soil respiration increased after simulated precipitation, but a rapid pulse of CO2 production did not appeared. Total C production from desert soil decreased with increasing precipitation. It was different at A. aphylla and H. caspica community. Soil CO2 efflux in growing season at woodland was larger than that at deserts, Populus﹥U. pumila﹥ T. ramosissima+ Ph. Communis﹥H. ammodendron﹥A. aphylla﹥H. caspica, they were 653.33, 301.85, 217.38, 119.19, 85.11, 69.08 gC m2-.
学科主题	系统生态学 ; 农学
公开日期	2010-11-12
页码	共142页
内容类型	学位论文
源URL	[http://ir.xjlas.org/handle/365004/8478]
专题	新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据)
推荐引用方式 GB/T 7714	张丽华. 干旱荒漠区不同生态系统土壤CO2释放通量研究[D]. 北京. 中国科学院．新疆生态与地理研究所. 2009.

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