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改变碳输入对樟树林土壤微生物数量和土壤酶活性的影响
Influence of Change Carbon Input on Soil Microbial Quantity and Enzyme Activity in Cinnamomum Camphora Plantation
【作者】 张明明；
【导师】 闫文德；
【作者基本信息】 中南林业科技大学 ， 生态学， 2012， 硕士
【摘要】 土壤微生物是土壤的重要组成部分,在土壤有机质的分解和养分循环中起重要作用。土壤酶是土壤有机体代谢的动力,在生态系统中起着重要的作用,土壤酶活性能直接反映土壤生物化学过程的强度和方向,土壤中所进行的一系列的生物化学反应都是在土壤酶的催化作用下完成的,土壤微生物数量、有机质含量等都与土壤酶活性的大小密切相关。本研究以亚热带典型森林生态系统—樟树人工林为研究对象,设计了添加凋落物(LAR)、去除凋落物(LRR)、去根添加凋落物(LANR)、去根去除凋落物(LRNR)和去根(CNR)5种碳输入处理试验,同时设置对照(CK),在诊断土壤理化性质的基础上,测定了不同碳输入处理条件下樟树林土壤微生物数量及土壤酶活性,分析了土壤酶活性和微生物数量的相互关系,研究结果将为揭示森林土壤碳通量机制和人工林的可持续经营提供理论依据。(1)樟树林中土壤理化性质。对照(CK)样地土壤全C含量15.28mg·g-1全N含量1.49mg·g-1,C/N为10.20,含水率为22.46%。改变凋落物的质、量可导致土壤的全C含量、全N含量及C/N比发生改变。土壤全C含量为：LAR最大(23.94mg·g-1),CNR最小(13.85mg·g-1)。添加凋落物使土壤全C含量显著增加,去根使土壤全C显著减少。土壤全N含量为：LRNR最大(2.10mg·g-1)去根去凋落物使土壤全N含量显著增加。C/N大小为：LAR最大(12.69),CNR最小(8.64),与土壤全C含量变化趋势大致相同。土壤含水率大小：LANR最大(23.16%),添加凋落物后土壤含水率增加。(2)樟树林微生物数量分布特征。对照和去除凋落物处理,微生物数量为：细菌>放线菌>真菌。去根、去根去除凋落物、添加凋落物和去根添加凋落物处理,微生物数量为：细菌>真菌>放线菌。从微生物数量的年变化规律看,添加凋落物使细菌、真菌和微生物总数量增加(LAR>LRR、LANR>LRNR);去除根系可使真菌、放线菌和微生物总数量下降(LAR>LANR、LRR>LRNR、CK>CNR)。4月、7月、10月,去根处理增加了细菌数量(CNR>CK)。4月、7月、10月,去除凋落物后,根系对真菌数量呈负效应(LRNR>LRR)。1月、4月、10月,添加凋落物使放线菌数量减少(CK>LAR)。凋落物和根系同时作用时,加强了两者的相互作用,对微生物数量的影响更为显著。(3)樟树林土壤酶活性。从土壤蛋白酶、脱氢酶、酸性磷酸酶、脲酶活性总体年变化规律看,添加凋落物可以提高蛋白酶、脲酶、脱氢酶和酸性磷酸酶活性,减少凋落物降低蛋白酶、脲酶、脱氢酶和酸性磷酸酶活性(LAK>LRR、 LANR>LRNR);去根系处理会减低蛋白酶、脲酶、脱氢酶和酸性磷酸酶活性,根系正效应明显(CK>CNR)。凋落物和根系同时作用时,显著的增加蛋白酶、脲酶、脱氢酶、过氧化氢酶活性和酸性磷酸酶活性(LANR>LRNR)。去除凋落物和添加凋落物,根系对过氧化氢酶活性呈负效应(IANR>LAR、LRNR>LRR)。(4)土壤微生物数量与土壤理化性质的相关性。凋落物处理(LAR、LRR):放线菌数量与全C、全N和C/N呈负相关,且相关性显著。根系处理(CK、CNR):真菌数量与全C和C/N呈正相关,相关性显著。凋落物和根系交互处理(LANR、 LAR、LRNR、LRR):放线数量与全N相关性显著。5种处理微生物与含水率相关性表现出于对照样地相同的规律,即细菌、真菌、放线菌和微生物总数均与含水率呈正相关。樟树林中放线菌可作为土壤有机质的生物指标。(5)土壤酶活性与土壤理化性质的相关性。凋落物处理(LAR、LRR):酸性磷酸酶与全C和C/N呈正相关,相关性显著。根系处理(CK、CNR):蛋白酶、酸性磷酸酶和脱氢酶与C/N呈正相关,相关性显著。凋落物和根系交互处理(LANR、LAR、LRNR、LRR):过氧化氢酶和全C和C/N呈正相关。蛋白酶和含水率呈正相关,相关性显著。樟树林中酸性磷酸酶和过氧化氢酶可作为土壤有机质含量的生物指标。(6)土壤微生物数量与土壤酶活性的相关性。土壤微生物数量与蛋白酶、脲酶、脱氢酶和酸性磷酸酶4种土壤酶表现出不同程度的相关性,而与过氧化氢酶没有相关性。凋落物处理(LAR、LRR):微生物总数与4种土壤酶相关性显著。根系处理(CK、CNR):蛋白酶与真菌和放线菌相关性显著。脲酶、酸性磷酸酶、脱氢酶与真菌、放线菌和微生物总数相关性显著。凋落物和根系处理(LANR、LAR、LRNR、LRR):细菌、微生物总数与4种土壤酶相关性显著。樟树林中凋落物处理时4种土壤酶活性可作为微生物总数的生物指标。根系处理时4种土壤酶活性可作为的真菌和放线菌生物指标。凋落物和根系处理时4种土壤酶活性可作为细菌、微生物总数的生物指标。
【Abstract】 Soil microorganism are main parts of the forestry ecosystem, and play vital roles in energy conversion, material cycling, development and maturation of soil. Soil enzyme plays an important role in the ecosystem, soil enzyme activity performance is a direct reflection of the strength and direction of soil biochemical processes. The number of microorganisms, organic matter content are closely related to the size of soil enzyme activity. Cinnamomum Camphor is a representative of subtropical evergreen broadleaf forest species. In this study, we treated with five treatments and control (CK), extra litter addition with root (LAR), litter removal with root (LRR), extra litter addition without root (LANR), litter removal without root (LRNR), control without root (CNR). We use traditional isolation methods to investigate soil properties, soil microorganism quantity, soil enzymes activity, and analysis the relation was conducted between the number of microorganism quantity and soil enzyme activity of the forest ecosystem,(1)CK:Total C (15.28mg-g-1), Total N (1.49mg-g-1), C/N (10.20), water content (22.46%). Total C:LAR reaches maximum value (23.94mg-g-1), CNR reaches minimum value(13.85mg-g-1). Soil total C content increased under add litter, soil total C content decrease without of roots. LRNR reaches maximum value (2.10mg·g-1), Soil total N content increase under litter removal without root. Soil C/N increase under add litter, LAR reaches maximum value (12.69). Soil C/N decreased under removal of roots, CNR reaches minimum value (8.64). Soil water content increase under add litter. LANR reaches maximum value (23.16%)(2) Microorganism quantities under CK, LRR showed that bacteria> actinomycetes>fungi; Microorganism quantities under LAR, LANR, LRNR, LRR show that bacteria>fungi>actinomycetes. Number of bacteria and fungi increased under add litter (LAR>LRR, LANR>LRNR); Number of bacteria and actinomycetes decreased under removal root (LAR>LANR, LRR> LRNR, CK>CNR). Number of bacteria under removal root decreased in April, July and October (CK>CNR); root has negative effect on number of fungi after removal litter in April, July, October (LRNR>LRR). Number of actinomycetes decreased under add litter (CK>LAR) The root and litter simultaneously effect on the number of microorganisms had obvious positive efficiency.(3) Protease, dehydrogenase, acidic phosphatase and urease activity improve under add litter (LAR>LRR, LANR>LRNR);protease, dehydrogenase, acidic phosphatease and urease activity declined under removal litter (CK>CNR). Root effect on Catalase activity had obvious negative efficiency under removal litter or add litter.(4) Correlation analysis of soil properties and microbial quantity showed that LAR, LRR:Actinomyces had significant negative correlation with total C, total N and C/N. CK, CNR:Fungi had significant positive correlation with total C and C/N. LANR, LAR, LRNR, LRR:Actinomyces had significant negative correlation with total N. Actinomyces, fungi and soil total microorganisms had positive correlation with soil water content under five treatments and CK. Therefore, actinomyces is suggested as the biological indicators of soil organic matter.(5) Correlation analysis of soil properties and enzyme activity showed that LAR, LRR:Acidic phosphatase has significant negative correlation with total C, total N and C/N. CK, CNR:Proteinase, Acidic phosphatase, dehydrogenase had significant positive correlation with C/N. LANR, LAR, LRNR, LRR:catalase had significant positive correlation with total C, C/N. Proteinase had positive correlation with soil water content under five treatments and CK. Therefore, catalase and Acidic phosphatase are suggested as the biological indicators of soil organic matter.(6) Correlation analysis of enzyme activity and microbial quantity showed that soil microbial quantity had correlation with four soil enzymes (Proteinase, dehydrogenase, urease, Acidic phosphatase), without catalase. LAR, LRR:soil microbial quantity had significant negative correlation with four soil enzyme. CK, CNR:Proteinase had significant correlation with actinomyces, fungi. Dehydrogenase, urease, Acidic phosphatase had significant correlation with actinomyces, fungi and total microbial quantity. LANR, LAR, LRNR, LRR:Bacteria, total microbial quantity had significant positive correlation with four soil enzymes. Therefore, soil enzyme activity is suggested as the biological indicators of microbial quantity.