林火对兴安落叶松林土壤微生物及酶活性的影响研究

发布时间：2018-07-30 06:40

【摘要】：本文以大兴安岭北部兴安落叶松林火烧迹地为研究对象,选取了1996年、2003年、2009年、2012年的火烧迹地,利用生化方法对不同程度火烧迹地土壤微生物数量、微生物量碳氮以及土壤酶活性的变化及各指标与环境因子间相互关系进行研究。目的是为火干扰后森林生态系统的恢复提供理论依据和参考。研究结果表明：1.不同程度火烧对土壤微生物数量的影响火烧迹地和未过火区土壤微生物数量均存在明显的月动态,在未过火区细菌和真菌数量月动态呈单峰状,分别在6月和7月值最大；放线菌数量在5月最大,呈递减趋势,在9月出现峰值。轻度火烧迹地微生物数量月动态与未过火区一致,重度火烧迹地微生物数量在个别月份与未过火区存在差异。火烧后不同年限、不同程度火烧迹地微生物数量变化不同。火烧后轻度火烧迹地放线菌和真菌数量增加,细菌数量经历了短暂的降低后增加,但随着时间的推移又逐渐降低,与未过火区间的差异逐渐缩小。重度火烧迹地微生物数量在火烧后短时间内均低于未过火区,随时间的变化规律不明显,但最终与未过火区的差异均不显著。在不同程度火烧迹地,环境因子对土壤微生物数量产生的影响不同。未过火区,微生物数量主要受到有机碳和全氮的影响。在轻度火烧迹地微生物数量不仅与有机碳和全氮相关,也与速效养分相关。在重度火烧迹地,微生物数量主要受到速效养分、pH和含水率等的影响。2.不同程度火烧对土壤微生物量碳、氮的影响火烧迹地和未过火区土壤微生物量碳、氮均存在明显的月动态,轻度火烧迹地和未过火区土壤微生物量碳、氮的月动态一致,表现为在7月出现峰值,在6月和9月分别出现极小值。重度火烧迹地土壤微生物量碳、氮含量分别在6月和7月出现最大值,并且均只在9月出现极小值。火烧迹地土壤微生物量碳、氮在火烧后1年低于未过火区,且随着火烧程度的增加,微生物量碳、氮降低的越多。在火烧2年以后,轻度火烧迹地土壤微生物量碳、氮均超过未过火区,并且直到火烧后18年,始终高于未过火区。而重度火烧迹地的土壤微生物量碳一直到火烧后18年始终低于未过火区,土壤微生物氮在火烧后18年才恢复至未过火区水平。土壤微生物量碳、氮在不同程度火烧迹地的影响因子存在差异。与未过火区相比,轻度火烧迹地微生物量碳与全氮、速效钾、全氮含量相关性增强,微生物量氮与pH相关性增强。重度火烧迹地,微生物量碳与全氮相关性增强,微生物量氮与有机碳相关性减弱。3.不同程度火烧对土壤酶活性的影响火烧迹地和未过火区土壤酶活性均表现出了明显的月动态变化,在未过火区土壤脲酶和蔗糖酶分别在7月和6月达到最大值,且均在9月为最小值：过氧化氢酶活性6月最小,8月最大。除重度火烧迹地过氧化氢酶活性以外,火烧迹地土壤酶活性均与为火烧区月动态变化一致。火烧后不同程度火烧迹地土壤酶活性在不同恢复年限存在差异。在轻度火烧迹地,过氧化氢酶恢复较快,在火烧后2年就恢复到了未过火区的水平,而脲酶和蔗糖酶分别在火烧后5年和11年才恢复到未过火区水平。重度火烧迹地,所有酶的活性经过多年的恢复依然低于未过火区。土壤脲酶和蔗糖酶对火烧较敏感,过氧化氢酶受火烧影响较少,土壤蔗糖酶受pH影响较大。火烧影响下不同土壤酶活性的影响因子发生了变化,与未火烧区相比,火烧迹地土壤酶活性受到微生物的影响增强。轻度火烧迹蔗糖酶活性与真菌相关性增强；重度火烧迹地蔗糖酶、脲酶与真菌相关性增强,过氧化氢酶与细菌相关性增强。
[Abstract]:In this paper, the burning slash of Larix gmelinii in northern Greater Khingan Range, Xingan, was studied. In 1996, 2003, 2009 and 2012, the number of soil microbes, the microbial biomass carbon and nitrogen, the change of soil enzyme activity and the relationship between the indexes and the environmental factors were studied by biochemical methods. The objective is to provide theoretical basis and reference for the restoration of forest ecosystem after fire interference. The results show that: 1. the effect of fire on soil microorganism quantity in different degrees of fire and the number of soil microbes in the burning and unburned areas have obvious monthly dynamics, and the monthly dynamics of bacteria and fungi in the unoverheated area are single peak, respectively, 6 The maximum value of the month and July, the number of actinomycetes in May, the decrease trend, the peak in September. The number of microbes in the mild burning trace is the same as that in the unburned area. The number of microbes in the severe burning trace is different from that in the unburned area in a few months. The number of actinomycetes and fungi increased in the light burning spot after fire, and the number of bacteria increased after a short period of decrease, but the difference gradually decreased with time. The number of microorganisms in the severe burned area was lower than that of the unburned area in a short time after the fire, and the law of change with time was unknown. The effects of environmental factors on the number of soil microbes were different in different degrees of fire. The number of microorganisms was mainly influenced by organic carbon and total nitrogen in the unburned area. The number of microbes in the light burned area was not only related to organic carbon and total nitrogen, but also related to the available nutrients. In the severe burning site, the number of microorganisms was mainly affected by available nutrients, pH and water content and so on. The effect of.2. on soil microbial biomass carbon in different degrees, the influence of nitrogen on the soil microbial biomass carbon in the burning and unoverheated areas, and the soil microbial biomass carbon in the light burning and unoverheated areas and the monthly dynamic of nitrogen The results showed that the peak value appeared in July and the minimum value in June and September. The soil microbial biomass carbon and nitrogen were maximum in June and July, respectively in June and July, and only in September. The soil microbial biomass carbon and nitrogen were lower in 1 years after the fire, and with the increase of fire degree, the microbiological amount of soil microbial biomass carbon and nitrogen were low. The amount of carbon and nitrogen decreased more. After 2 years of fire, the soil microbial biomass carbon and nitrogen in the light burned ground exceeded the unburned area and remained higher than the unoverheated area until 18 years after the fire. And the soil microbial biomass of the severe burned soil remained low in the 18 year after the fire, and the soil microbial nitrogen was only 18 years after the fire. The influence factors of soil microbial biomass carbon and nitrogen in different burned areas were different. Compared with the unburned area, the correlation between microbial biomass carbon and total nitrogen, available potassium and total nitrogen in the light burned area increased, the correlation of microbial biomass nitrogen and pH increased. The correlation between microbial biomass carbon and total nitrogen was related to the severe burning site. The correlation between microbial biomass nitrogen and organic carbon decreased the effect of.3. on soil enzyme activity in different degrees. The activity of soil enzyme in the burning and unburned areas showed significant monthly dynamic changes. The soil urease and sucrase reached the maximum in July and June in the unoverheated area, and all in September were the minimum value of catalase. The activity in June was the smallest and the largest in August. In addition to the activity of the catalase in the severe burning trace, the activity of soil enzyme in the burned area was the same as that of the monthly dynamic change in the burning area. The soil enzyme activity in different burned sites after fire was different. The catalase was recovered rapidly in the light burning slash, and it was restored in 2 years after the fire. The urease and sucrase were restored to the level of the unburned area only 5 and 11 years after the fire, and the activity of all enzymes was still lower than the unoverheated area. The soil urease and sucrase were more sensitive to fire, and the hydrogen peroxide enzyme was less affected by fire, and the soil invertase was affected by pH shadow. The influence factor of the enzyme activity of different soils changed under the influence of fire. Compared with the unburned area, the activity of soil enzyme was enhanced by microorganism. The activity of sugarcane sugar enzyme was enhanced with the fungi; the correlation between the invertase, urease and fungi in the severe burning trace, the catalase and the bacteria were increased. Correlation enhancement.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S762;S714.3

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