【作者】 翟心心；

【导师】 袁道先；

【作者基本信息】 西南大学 ， 自然地理学， 2011， 硕士

【摘要】 土壤酶是土壤生态系统中的重要组成部分,是土壤生物化学过程的积极参与者,是生态系统中物质循环和能量流动过程中最为活跃的生物活性物质,它在陆地生态系统地下生态过程中十分重要。土壤空气中的CO2浓度很高,通常是大气中CO2浓度的几十至上百倍。而对于岩溶区而言,在其特殊的地质背景条件下,土壤中的CO2浓度更是比非岩溶区土壤要高,但以往的研究主要集中在大气CO2浓度升高对土壤酶活性的影响,未研究过土壤CO2浓度及其变化对土壤酶活性的影响。但是这二者之间的关系对于揭示岩溶区土壤,及岩溶生态系统与其他生态系统的差别极有意义,也对岩溶区农业经济合理发展和生态恢复有重要的科学意义。本研究以重庆青木关岩溶槽谷区作为研究区,根据研究需要避免复杂因素干扰,选择受人类活动影响较少的,青木关地下河流域的上中游槽房湾至金竹湾一段为主要研究区。选取洼地、坡地两种地貌的草地、灌丛地和竹林地三种主要土地利用类型,在冬季、夏季、秋季三个季节分0-20cm、20-40cm、40-60cm、60-80cm进行取样和土壤CO2监测,监测其土壤酶活性。根据所得数据,揭示岩溶槽谷区土壤CO2浓度的垂直分布规律及季节变化规律；岩溶槽谷区士壤酶活性的垂直分布规律及季节变化规律；以及岩溶槽谷区土壤CO2浓度变化与土壤酶活性变化之间的相互关系,讨论土壤CO2浓度对土壤酶活性的影响。从而,为揭示岩溶区生态环境特殊性以及为岩溶区合理发展生态农业提供科学依据。通过为期一年的青木关野外土壤CO2浓度监测,得到了岩溶槽谷区不同地貌位置,不同土地利用方式下,在一年内的土壤CO2浓度变化趋势图。青木关岩溶槽谷区土壤CO2浓度变化的总体规律是：土壤CO2浓度值随着土层深度增加而增加,同一个月份中,最底层的土壤CO2浓度值最大,最表层的土壤CO2浓度值最小；不同地貌部位土壤CO2浓度不同,洼地的土壤CO2浓度高于坡地：不同植被类型条件下的土壤CO2浓度变化幅度不同,草地的土壤CO2浓度增幅最大,灌丛地次之,竹林地增幅最小。本研究检测了总共135个土壤样品当中的士壤蔗糖酶活性、脲酶活性、碱性磷酸酶活性、淀粉酶活性和过氧化氢酶活性,得到了这些土壤酶在不同季节、不同深度的活性值。发现土壤中蔗糖酶、脲酶、碱性磷酸酶、淀粉酶的总体规律为表现为表层酶活性大于底层酶活性,有的样品有由表层向底层逐渐降低的垂直分布形势。且这四种酶类的活性随季节变化发生变化。但土壤过氧化氢酶活性的分布规律非常不明显,表层和底层之间没有明显的变化趋势,各个季节之间也没有明显的规律变化。此外,洼地的采样点与位于坡地的采样点相比,具有更加明显的垂直和季节变化规律。通过SPSS进行相关分析、通径分析,其结果表明在青木关岩溶槽谷区,土壤CO2浓度与土壤酶活性具有一定的相关关系,不论从不同季节讨论还是从不同土壤层次讨论,土壤CO2浓度都会对土壤酶活性产生影响。从季节上分析,土壤CO2浓度对士壤酶活性的影响较大,并且主要表现在通过其他要素而产生的间接影响方面,其中对蔗糖酶和脲酶活性的影响强度最大,其强度绝对值高于0.3,而其他酶类仅为0.1至0.2。从不同土壤层次上分析,土壤CO2浓度对土壤酶活性的影响主要表现在直接影响方面,其中在各个层次对蔗糖酶和淀粉酶活性的影响强度最大,其强度绝对值在0.3左右。同时,不同土壤CO2浓度变化幅度也会对土壤酶活性产生影响,变幅较大的对土壤酶活性的影响较大,并主要通过对土壤酶的间接影响表现出来,变幅较小的对土壤酶活性的影响较小,并主要对土壤酶产生直接影响。因此,土壤CO2浓度对于水解酶类的蔗糖酶影响最大,对淀粉酶和碱性磷酸酶的影响次之,对脲酶的影响最小,而对于氧化还原酶类的过氧化氢酶影响较大。由于土壤CO2浓度对土壤酶活性的影响,岩溶区的土壤-植被系统甚至陆地生态系统也受到了相应的影响。土壤CO2浓度变化对蔗糖酶有积极影响,也促使他对生态系统产生积极影响；土壤CO2浓度变化对淀粉酶和碱性磷酸酶有抑制作用,也促使他们对生态系统产生消极影响；土壤CO2浓度变化对脲酶的抑制作用很小,因此对生态系统的影响较小；土壤CO2浓度变化对过氧化氢酶影响较大,也促使他对生态系统产生消极影响。更多还原

【Abstract】 Soil enzymes are important components and active participants in the soil biochemical processes, and the most vigorous biological-active substances in the process of material circulation and energy flow in the soil ecosystem. They also are very important for the underground ecological processes of terrestrial ecosystems. The carbon dioxide concentration in karst soil is high, which is tens or hundreds times of atmospheric carbon dioxide concentration. The concentration of soil carbon dioxide in karst area is higher than the non-karst area, for the particularly geological background in the karst zone. Previous studies were focused on atmospheric carbon dioxide concentration affected on soil enzyme activities, rarely discussed the changes in soil carbon dioxide concentration and its effect on soil enzyme activities. It is important for revealing the difference in the soil and ecosystem between karst and non-karst zone, and the rational development of agricultural economy and ecological restoration in karst area to study on this relationship.Qingmuguan karst valley in Chongqing is selected as the study area in this research. According to research needs to avoid interference complex factors, we choose the less affected area by human activities, from the Caofangwan to Jinzhuwan which covers the upper and middle stream of Qingmuguan underground river as the main study zone. During winter, summer, and autumn;we select three main land use types at depressions and slopes:grassland, shrub land and bamboo land, and at 0-20cm,20-40cm,40-60cm,60-80cm we sampling and monitoring the soil carbon dioxide concentration,and then testing their soil enzymes activity. According to the data, we reveal the rule of the concentration of soil carbon dioxide in karst valley in the vertical distribution and seasonal variation; and reveal the rule of soil enzymes activity in karst valley in the vertical distribution and seasonal variation;and reveal the relationship between the concentration of soil carbon dioxide concentration and activity of soil enzymes in karst valley, and then discuss the soil carbon dioxide concentration effect on soil enzyme activities. Thus, it revealing the particularity of ecological environment in karst zone and providing scientific supporting for rational development of ecological agriculture in karst zone.By a one-year field monitoring of soil carbon dioxide concentration in Qingmuguan karst valley, we get the karst valley soil carbon dioxide concentration trend figure during one year, which is in the different landscape positions and different land use patterns. The variation of soil carbon dioxide concentration in Qingmuguan karst valley in the general is:With the increase of soil depth, soil carbon dioxide concentration increased. In a same month, the soil carbon dioxide concentration was highest at the bottom and lowest at the surface. The concentration of soil carbon dioxide is different in different landform position:soil carbon dioxide concentration at depressions is higher than at slopes. The variation amplitude of soil carbon dioxide concentration is different under different vegetation types:the grass soil carbon dioxide concentrations have the largest increase, followed by shrub land, and then bamboo ground.In this issue,135 soil samples were tested in soil invertase activities、soil urease activities、soil alkaline phosphatase activities、soil amylase activities and soil catalase activities. And we got these soil enzymes activity values in different seasons and different depths. This study fonud the general rule of soil invertase, urease, alkaline phosphatase and amylase were surface enzyme activities were larger than bottom, some samples to bottom by surface gradually decreasing vertical distribution situation. And the four enzyme activity changes with the season variety. But the variations of soil catalase activities in temporal and spatial distribution were not obvious. There was no obvious change rules form surface to bottom and no obvious change rules between each season. In addition, depression sites have more significant vertical distribution and seasonal variation than slope sites.The results show that soil carbon dioxide concentration has a certain relationship with soil enzyme activity in Qingmuguan karst valley by the correlation, path analysis. Even more, regardless of different seasons or different soil layers, the soil carbon dioxide concentration will have an impact on soil enzyme activities. From the seasonal analysis, soil carbon dioxide concentrations have larger effect on soil enzyme activities, and mainly indirectly impact the enzymes activities through the other chemical properties. This impact was most obviously on invertase and urease. The strength values of these two enzymes were over 0.3. and others were between 0.1 and 0.2. Soil carbon dioxide concentration shows directly influence on soil enzyme activities by analysis different layers of soil, and have most significant impact on invertase and urease in each layers, the value was about 0.3. The amplitude of soil air concentration would affect soil enzymes activities. Lager amplitude has a significant impact on soil enzymes activities and mainly shows indirectly influence on soil enzymes activities, otherwise smaller amplitude has a minor impact on soil enzymes activities and mainly shows directly impact. Thus. Soil carbon dioxide concentration has significant impact on soil hydrolysis enzymes, and mostly on invertase. Amylase and alkaline phosphatase were less affected, urease was least affected, and catalase of soil redox enzymes was greater affected by soil carbon dioxide concentration.The soil-vegetation system and terrain ecosystem was affected by soil carbon dioxide concentration, for its impacts on soil enzymes activities. The positive influence on invertase by variation of soil carbon dioxide concentration would attribute to promote the ecosystem status; the inhibition on amylase and alkaline phosphatase would cause negative influence on ecosystem; the variation of soil carbon dioxide concentration has less impact on urease., thus there was litter influence on ecosystem.And soil carbon dioxide concentration had greater impact on catalase and it would cause negative influence on ecosystem.更多还原