發(fā)布時間：2018-02-27 00:21

  本文關(guān)鍵詞： 喀斯特 土壤酶活性 土壤理化屬性 樹種 不同土地利用方式　出處：《廣西師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：土壤有機質(zhì)分解是大氣二氧化碳(CO2)的主要來源,也是生態(tài)系統(tǒng)內(nèi)部碳、氮、磷等物質(zhì)循環(huán)的關(guān)鍵步驟。土壤中的有機質(zhì)需要經(jīng)過胞外酶(除非特別說明,以下所指的土壤酶均指胞外酶)的解聚作用(Depolymerization)生成小分子或單分子有機物后,微生物才能直接吸收利用,土壤碳、氮、磷等物質(zhì)循環(huán)的后續(xù)過程才能順利進行。正因為如此,由土壤酶主導(dǎo)的大分子有機質(zhì)解聚這一步驟往往成為土壤碳、氮、磷循環(huán)的限制性環(huán)節(jié)�？梢�,土壤酶在生態(tài)系統(tǒng)物質(zhì)循環(huán)和能量流動中扮演著重要角色,深入認(rèn)識土壤酶活性對于理解生態(tài)系統(tǒng)碳、氮、磷元素生物地球化學(xué)循環(huán)過程具有重要意義�？λ固厣鷳B(tài)系統(tǒng)是地球表層系統(tǒng)的重要組成部分。由于其地質(zhì)背景的特殊性,喀斯特生態(tài)系統(tǒng)的生物地化循環(huán)存在特異性,這可能導(dǎo)致土壤胞外酶活性及其主控因素有別于其它生態(tài)系統(tǒng)。然而,目前對西南喀斯特山區(qū)典型生態(tài)系統(tǒng)土壤胞外酶活性及其主控因素的研究非常缺乏。本研究以典型喀斯特生態(tài)系統(tǒng)為對象,首先研究了不同植被恢復(fù)階段(農(nóng)田、草地、灌叢、次生林)土壤碳、氮和磷轉(zhuǎn)化相關(guān)胞外酶活性及其主控因素;在此基礎(chǔ)上,對典型喀斯特與相鄰非喀斯特森林土壤胞外酶活性開展了對比研究。研究得到的主要結(jié)論如下:(1)喀斯特山區(qū)植被恢復(fù)過程中,土壤水解酶(參與活性碳庫的分解)和氧化酶活性(參與惰性碳庫的分解)的響應(yīng)結(jié)果顯示,隨著植被恢復(fù),土壤水解酶(即β-葡糖苷酶、α-纖維素酶和β-木糖苷酶)活性不斷增加(即次生林灌叢草地農(nóng)田),土壤氧化酶(過氧化物酶)活性無明顯變化�？λ固氐貐^(qū)退耕后,隨著植被恢復(fù),氮循環(huán)酶(即亮氨酸氨基肽酶、幾丁質(zhì)酶、脲酶、蛋白酶)活性不斷增加。相關(guān)性分析發(fā)現(xiàn)脲酶和蛋白酶與有機質(zhì)和全氮極顯著相關(guān)。磷酸酶的活性與土壤pH和交換性鎂離子有相關(guān)性,而與其他理化性質(zhì)無明顯相關(guān)性,綜合分析表明:喀斯特地區(qū)土壤交換性鎂離子對酸性磷酸酶具有正效應(yīng),而對堿性磷酸酶無顯著效應(yīng);土壤理化指標(biāo)與磷酸酶活性相關(guān)性分析發(fā)現(xiàn),喀斯特地區(qū)土壤磷酸酶除受pH以及交換性鎂離子的影響外,與其它所測理化指標(biāo)均無顯著相關(guān)性。(2)喀斯特與非喀斯特地區(qū)酶活性對比研究發(fā)現(xiàn),兩個地區(qū)屬于不同的土壤類型,喀斯特地區(qū)(堿性的鈣質(zhì)土壤)酶活性普遍高于非喀斯特地區(qū)(酸性的紅壤),除了酸性磷酸酶和幾丁質(zhì)酶活性外,其它所測的八種酶活性在喀斯特地區(qū)均顯著大于非喀斯特地區(qū),兩種土壤類型的酶活性受控因子也不同,喀斯特地區(qū)受控因子較非喀斯特地區(qū)影響因子更集中。(3)通過方差分解的方法分析了樹種、土壤理化性質(zhì)和土壤類型三組解釋變量對土壤酶活性的相對貢獻,結(jié)果顯示:三組解釋變量總共解釋了土壤酶活性變異的62.6%。其中,土壤理化性質(zhì)解釋了土壤酶活性變異的58.2%,土壤類型解釋了土壤酶活性變異的38.7%,樹種因子解釋了土壤酶活性變異的27.8%。三組變量存在交互作用,三者共同解釋的部分為17.8%。當(dāng)剔除了兩兩間共同解釋部分后,土壤理化性質(zhì)凈解釋了土壤酶活性變異的23.4%,土壤類型凈解釋了土壤酶活性變異的3.9%,樹種因子凈解釋了土壤酶活性變異的0.9%。
[Abstract]:Soil organic matter decomposition is atmospheric carbon dioxide (CO2) is the main source of internal ecosystem carbon, nitrogen, phosphorus and other key steps of material circulation. The organic matter in the soil by extracellular enzymes (enzyme unless otherwise specified, the following refers to the mean extracellular solution) poly (Depolymerization) generates a small role single molecule or molecular organic matter, microbes can be directly absorbed by soil carbon, nitrogen, phosphorus and other substances to the subsequent process of circulating smoothly. Because of this, the steps of macromolecular organic matter was dominated by soil enzymes often become soil carbon, nitrogen, phosphorus cycle restriction factors. Therefore, soil enzyme plays an important role in the material cycle and energy flow in ecosystem, in-depth understanding of soil enzyme activity to the understanding of ecosystem carbon, nitrogen, phosphorus plays an important role in the biogeochemical cycle of Karst ecosystem. The system is an important part of the earth surface system. Because of its special geological background, Karst ecosystem biogeochemical cycles in the presence of specific, which may lead to soil extracellular enzyme activity and its main controlling factors are different from other ecosystems. However, the current research on the southwest Karst area of typical soil ecological system and its extracellular enzyme activity the main control factors is lacking. In this study, the typical Karst ecological system as the object, firstly study the different vegetation restoration stages (farmland, grassland, shrub, secondary forest) of soil carbon, nitrogen and phosphorus transformation related extracellular enzyme activity and its main controlling factors; on this basis, the typical Karst and adjacent Karst forest soil enzyme the activity to carry out a comparative study. The main conclusions are as follows: (1) in the process of vegetation restoration in Karst mountain area, soil hydrolase (involved in the decomposition of active carbon pool) and oxygen Enzyme activity (in inert carbon decomposition) the response results show that, with the vegetation restoration, soil hydrolase (i.e. beta glucosidase, alpha cellulose and beta xylosidase) activity increased (i.e., secondary forest, shrub grassland farmland) soil enzymes (peroxidase) activity had no obvious change in Karst area. After returning, along with vegetation restoration, the nitrogen cycle enzyme (i.e., leucine aminopeptidase, chitinase, urease, protease) activity increased. Correlation analysis showed that urease and protease and organic matter and total nitrogen were significantly correlated. The phosphatase activity and soil pH and exchangeable magnesium ions are related, but had no correlation with other physical and chemical nature, comprehensive analysis showed that: Karst area soil exchangeable magnesium ion has a positive effect on acid phosphatase, but no significant effect on alkaline phosphatase; analysis of the correlation between physicochemical indexes and soil phosphatase activity Found that the Karst area affected by soil phosphatase pH and exchangeable magnesium ions, there was no significant correlation with other measured physicochemical indexes. (2) Comparative Study on enzyme activity of Karst and non Karst area found that two regions belong to different soil types, the Karst area (alkaline calcareous soil) enzyme activity is generally higher than non Karst area (acid red soil), in addition to acid phosphatase and chitinase activity, measured by the other eight kinds of enzyme activity in the Karst area were significantly higher than non Karst area, two types of soil enzyme activity of the controlled factors are different, the Karst area controlled factor of non Karst area influence factor is more concentrated. (3) through the variance decomposition analysis of tree species, soil properties and soil type three sets of explanatory variables on soil enzyme activity results showed that the relative contribution of the three sets of explanatory variables in total solution The release of soil enzyme activity variation of 62.6%. among them, soil physical and chemical properties explained 58.2% of the variation of soil enzyme activity, soil type explained 38.7% of the variation of soil enzyme activity, species factors explain interaction between soil enzyme activity variation of 27.8%. three group variables, three common interpretation of the part is 17.8%. when excluding the 22 the common explanation part, the physical and chemical properties of soil net explained 23.4% of variation in soil enzyme activity, soil type net explain 3.9% of the variation of soil enzyme activity, net factor explains the species variation of soil enzyme activity 0.9%.

【學(xué)位授予單位】：廣西師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：S154.2

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