常绿阔叶林改造为毛竹林对土壤呼吸组分与活性碳库的影响

发布时间：2018-07-29 18:56

【摘要】：土地利用变化显著影响土壤碳库与土壤呼吸过程。天然林改造为人工林在带来较高经济效益的同时,由于植被性质和经营管理方式的改变,群落物种组成、凋落物特征、土壤物化和生物学性质也发生了根本性的转变,从而显著影响土壤的碳库动态特征。毛竹是我国南方重要的人工林资源,占全国竹林面积的70%左右,在亚热带区域碳平衡中扮演着重要角色。近年来,很多营林者为了提高经济效益,将天然常绿阔叶林改造为毛竹林,并采取了施用化肥、增加翻耕次数以及去除林下杂草等集约经营措施。上述土地利用变化及相关经营措施的实施,将显著影响土壤碳过程,然而,目前对其影响机理尚缺乏深入系统的研究。本项目以天然常绿阔叶林和由其改造后的毛竹人工林为研究对象,通过为期1年的定位试验,研究了上述两种林地土壤呼吸组分(包括土壤总呼吸、自养呼吸与异养呼吸)与环境因子(包括土壤温度、土壤含水量、水溶性有机碳含量和微生物量含量)的动态变化特征,探明了常绿阔叶林改造为毛竹林对土壤呼吸组分与活性碳库的影响机理,分析了土壤呼吸各组分和环境影响因子之间的相互关系。取得的主要研究结果如下:(1)常绿阔叶林和毛竹人工林土壤总呼吸、自养呼吸和异养呼吸均呈现显著的季节变化特征。两个林地土壤总呼吸速率最大值出现在夏季,最小值出现在冬季。两个林地土壤的自养呼吸速率夏季最高,冬季最低;而异养呼吸秋季最高,冬季最低。(2)常绿阔叶林和毛竹林土壤呼吸年累积CO2排放量分别为31.60和37.25 t CO2hm-2 yr-1。常绿阔叶林土壤总呼吸速率、异养呼吸速率、自养呼吸速率年平均值分别为2.48、1.57和0.91μmol CO2 m-2 s-1;毛竹林土壤总呼吸速率、异养呼吸速率和自养呼吸速率的年平均值分别为2.93、1.92和1.01μmol CO2 m-2 s-1。两林地土壤均表现为异养呼吸在土壤呼吸中所占比例较大。常绿阔叶林、毛竹人工林土壤异养呼吸分别占土壤总呼吸的63.57%和66.07%,自养呼吸所占比例为36.43%和33.93%。常绿阔叶林改造为毛竹林后,土壤总呼吸、异养呼吸和自养呼吸年累积CO2排放量分别增加了17.87%、22.51%和9.78%。(3)常绿阔叶林和毛竹林土壤的水溶性有机碳(WSOC)和微生物量碳(MBC)含量均具有明显的季节变化特征。常绿阔叶林和毛竹林土壤WSOC含量最低值均出现在2月,最高值出现在6月。常绿阔叶林土壤MBC含量夏秋季节较高,冬季较低;毛竹林土壤MBC含量在10-12月份较高,在7-8月较低,最低值出现在2月。常绿阔叶林改造成毛竹林后,土壤WSOC含量增加了10.26%,而土壤MBC含量则下降了6.23%。(4)常绿阔叶林和毛竹人工林土壤呼吸各组分均与土壤温度(表层5 cm处)呈极显著相关(P0.01)。常绿阔叶林和毛竹林土壤总呼吸、异养呼吸、自养呼吸速率的温度敏感系数(Q10)值分别为1.80、1.92、1.70和2.05、1.95、2.34。常绿阔叶林异养呼吸的温度敏感性更高,而毛竹人工林是自养呼吸对温度的敏感性最高。(5)常绿阔叶林土壤总呼吸、异养呼吸与土壤WSOC含量均呈极显著相关(P0.01),毛竹林土壤总呼吸、异养呼吸与土壤WSOC含量均呈显著相关(P0.05)。两个林地土壤的自养呼吸与土壤WSOC含量均无显著相关性。两个林地土壤呼吸各组分与土壤含水量及土壤MBC含量之间均无显著相关性。
[Abstract]:The change of land use change significantly affects soil carbon storage and soil respiration. The transformation of natural forest to artificial forest has brought about higher economic benefits. As a result of the change of the nature of vegetation and management mode, the species composition, litter characteristics, soil physicochemical and biological properties of the community also changed radically, which significantly affected the soil. The dynamic characteristics of carbon storage, bamboo is an important artificial forest resource in the south of China, accounting for about 70% of the area of bamboo forest in the country, and plays an important role in the carbon balance in the subtropical region. In recent years, in order to improve the economic benefits, many forest reforers have transformed the natural evergreen broad-leaved forest into Mao Zhulin, and used chemical fertilizer to increase the number of ploughing and to increase the number of ploughing and to increase the number of ploughing and to increase the number of ploughing. In addition to the intensive management measures such as weeds under forest, the change of land use and the implementation of related management measures will significantly affect the soil carbon process. However, the mechanism of its influence is still lacking in deep systematic study. The project is based on the natural evergreen broad-leaved forest and the reconstructed bamboo man Industrial forest, through a 1 year positioning test. The dynamic changes of the two kinds of forest soil respiration components (including soil total respiration, autotrophic respiration and heterotrophic respiration) and environmental factors (including soil temperature, soil water content, water soluble organic carbon content and microbial biomass content) were studied, and the transformation of evergreen broad-leaved forest to Mao Zhulin's soil respiration component and active carbon pool was explored. The relationship between soil respiration components and environmental impact factors was analyzed. The main results were as follows: (1) the soil respiration of evergreen broad-leaved forest and Phyllostachys pubescens plantation, autotrophic respiration and heterotrophic respiration showed significant seasonal variation. The maximum value of total soil respiration rate of two woodlands appeared in summer, The minimum value occurred in winter. The respiration rate of two woodland soils was the highest in summer and lowest in winter, while heterotrophic respiration was the highest in autumn and lowest in winter. (2) the annual cumulative CO2 emission of soil respiration in evergreen broad-leaved forest and bamboo forest was 31.60 and 37.25 t CO2hm-2 yr-1. evergreen broad-leaved forest soil total respiration rate, heterotrophic respiration rate, autotrophic respiration The annual mean absorption rate is 2.48,1.57 and 0.91 mol CO2 m-2 s-1, and the annual average soil respiration rate, heterotrophic respiration rate and autotrophic respiration rate of the bamboo forest are 2.93,1.92 and 1.01 Mu mol CO2 m-2 s-1. two, respectively, which show the proportion of heterotrophic respiration in soil respiration. The soil heterotrophic respiration accounted for 63.57% and 66.07% of the total soil respiration, and the proportion of the autotrophic respiration was 36.43% and the 33.93%. evergreen broad-leaved forest was transformed into the bamboo forest. The total soil respiration, heterotrophic respiration and autotrophic respiration increased by 17.87%, 22.51% and 9.78%. (3) evergreen broad-leaved forest and the water soluble organic carbon in the soil of 9.78%. (3). The content of (WSOC) and microbial biomass carbon (MBC) had obvious seasonal variation. The minimum value of WSOC content in evergreen broad-leaved forest and Mao Zhulin soil appeared in February, the highest value appeared in June. The soil MBC content of evergreen broad-leaved forest was higher in summer and autumn and lower in winter; the MBC content in soil of bamboo forest was higher in 10-12 month, lower in 7-8 months, the lowest value was out. In February, after the transformation of evergreen broad-leaved forest into bamboo forest, soil WSOC content increased by 10.26%, while soil MBC content decreased by 6.23%. (4) evergreen broad-leaved forest and Phyllostachys pubescens soil respiration each component was significantly correlated with soil temperature (5 cm) (P0.01). Evergreen broad-leaved forest and bamboo forest soil total respiration, heterotrophic respiration, autotrophic respiration The temperature sensitivity coefficient (Q10) of absorption rate was higher in 1.80,1.92,1.70 and 2.05,1.95,2.34. evergreen broad-leaved forests, while the sensitivity of autotrophic respiration to temperature was the highest. (5) the total respiration of soil in evergreen broad-leaved forest, heterotrophic respiration and soil WSOC content were significantly correlated (P0.01), and the bamboo forest soil was very significant (P0.01). There was significant correlation between soil total respiration, heterotrophic respiration and soil WSOC content (P0.05). There was no significant correlation between the autotrophic respiration of two woodland soils and the content of soil WSOC. There was no significant correlation between the two soil respiration components and the soil water content and the soil MBC content.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714

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