长期集约经营对雷竹林土壤温室气体排放的影响

发布时间：2018-05-22 18:58

本文选题：集约经营 + 雷竹林　；参考：《浙江农林大学》2017年硕士论文

【摘要】：森林是全球最大的陆地生态系统,森林土壤是CO_2、CH_4、N_2O等温室气体重要排放源或吸收汇。集约经营改变了森林土壤理化性质,影响了植物根系的生长和微生物的活性,导致森林土壤碳、氮循环发生改变进而影响土壤温室气体的排放。雷竹(Phyllostachys praecox)是我国优良的笋用竹,广泛分布于长江以南地区,目前仅浙江省雷竹林面积就达6.7万hm2,占全省经济林面积的7.7%。上世纪80年代以来,以施肥和覆盖为核心的集约经营措施提高了雷竹的经济效益,但同时导致土壤酸化、养分过量积累以及有机碳稳定性下降等问题,目前雷竹林长期集约经营过程中土壤温室气体排放的动态变化规律及其机理尚缺乏深入系统的研究。本研究利用空间代替时间的方法,以不同集约经营时间(1、5、10、20和30年)雷竹林作为研究对象,利用静态箱-气相色谱法研究长期集约经营过程中雷竹林土壤温室气体排放特征,结合土壤水溶性碳、氮和微生物生物量碳、氮的季节动态变化规律,探讨长期集约经营雷竹林土壤温室气体排放的动态变化机理,为科学评估经营管理对土壤温室气体排放的影响提供科学支撑。研究结果如下:(1)随集约经营时间的增加,雷竹林表层土壤有机碳、全氮、碱解氮、有效磷、速效钾含量均显著提高(P0.05),土壤容重、土壤pH值显著降低(P0.05)。雷竹林土壤水溶性有机碳(WSOC)、水溶性有机氮(WSON)、NH_4+-N、NO3--N、微生物生物量碳(MBC)和微生物生物量氮(MBN)含量均随集约经营时间的增加而增加(P0.05),MBC和MBN在集约经营20年时达到最大值,随后呈现降低趋势。(2)雷竹林土壤CO_2排放通量呈明显的季节变化,即春夏季高、秋冬季低。集约经营1年、5年、10年、20年和30年雷竹林土壤CO_2年均排放通量分别为:338.89、337.53、374.52、491.10和364.14 mg·CO_2·m-2·h-1,在20年时达到最大值,随后呈现降低趋势。1年、5年、10年和30年雷竹林土壤CO_2年累积排放量没有明显差异。长期集约经营显著增加了20年雷竹林土壤CO_2年累积排放量(P0.05)。雷竹林土壤CO_2排放通量与地下5cm土壤温度具有极显著相关性(P0.01)。除集约经营20年雷竹林外,其余集约经营年份土壤CO_2排放通量均与WSOC呈显著正相关(P0.05)。雷竹林土壤CO_2排放通量与土壤含水量、MBC没有相关性。(3)雷竹林土壤N_2O排放通量具有明显的季节变化,即春夏季高、秋冬季低。集约经营1年、5年、10年、20年和30年雷竹林土壤N_2O年均排放通量分别为:54.10、155.19、202.34、246.53和315.17μg·N_2O·m-2·h-1。长期集约经营显著增加了雷竹林土壤N_2O年累积排放量(P0.05),具体表现为:集约经营5年、10年、20年和30年雷竹林土壤N_2O年累积排放量分别是1年的3.07、3.48、4.00和5.74倍。集约经营10年、20年和30年雷竹林土壤N_2O排放通量与地下5cm土壤温度具有显著相关性(P0.05)。集约经营5年、10年和30年雷竹林土壤N_2O排放通量与土壤WSON具有显著相关性(P0.05)。集约经营10年和30年土壤N_2O排放通量与土壤NH_4+-N具有显著相关性(P0.05)。土壤含水量、MBN、NO3--N与土壤N_2O排放通量没有相关性。(4)雷竹林土壤CH_4排放通量没有明显的季节变化;集约经营显著增加了土壤CH_4年累积排放量(P0.05),并使土壤由CH_4吸收汇转变为CH_4排放源。集约经营1年、5年、10年、20年和30年雷竹林土壤CH_4年累积排放量分别为:-0.05、2.89、3.28、6.22和0.80 kg·CH_4·hm-2·a-1。集约经营5年土壤CH_4排放通量与地下5 cm土壤温度具有显著相关性(P0.05),其余集约经营年份土壤CH_4排放通量与地下5 cm土层土壤温度均无相关性。土壤CH_4排放通量与土壤含水量、WSOC、MBC均没有相关性。(5)集约经营1年、5年、10年、20年和30年雷竹林土壤排放温室气体的综合温室总效应分别为:30.15、33.99、37.19、45.52和39.18 Mg·CO_2-e·hm-2·a-1。集约经营显著增加了雷竹林土壤排放温室气体的综合温室效应,随集约经营时间的增加,雷竹林土壤排放温室气体的综合温室效应逐渐增加(P0.05),在集约经营20年时达到最大值,随后呈现降低趋势。
[Abstract]:Forest is the largest terrestrial ecosystem in the world. Forest soil is an important source of greenhouse gases such as CO_2, CH_4 and N_2O. Intensive management has changed the physical and chemical properties of forest soil, influenced the growth of plant roots and the activity of microorganism, resulting in the change of carbon and nitrogen cycle in the forest soil and the influence of the emission of soil greenhouse gas. Bamboo (Phyllostachys praecox) is a fine bamboo shoot in China, which is widely distributed in the south of the Yangtze River. At present, the area of Lei Zhulin in Zhejiang province is 67 thousand Hm2, which accounts for the economic forest area of the province. Since 80s of the last century, the intensive management measures with fertilizer and cover as the core have improved the economic benefit of the bamboo, but at the same time it leads to soil acidification. The dynamic changes of soil greenhouse gas emissions in the long term intensive management of the bamboo forest and its mechanism are still lacking in deep systematic study. This study uses space instead of time to study the bamboo forest of different intensive management time (1,5,10,20 and 30 years). Object, using static box gas chromatography to study the characteristics of greenhouse gas emission from bamboo forest soil in long term intensive management, combined with the seasonal dynamic changes of soil water soluble carbon, nitrogen and microbial biomass carbon and nitrogen, to explore the dynamic change mechanism of greenhouse gas emission in long term intensive management of Lei bamboo forest, and to evaluate management management for scientific management. The research results are as follows: (1) with the increase of intensive management time, the soil organic carbon, total nitrogen, alkali hydrolysable nitrogen, available P, and available potassium in the surface soil of Lei bamboo forest increased significantly (P0.05), soil bulk density, soil pH value decreased significantly (P0.05). The water soluble organic carbon (WSOC) and water solubility in the soil of Lei bamboo forest The content of sexual organic nitrogen (WSON), NH_4+-N, NO3--N, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) increased with the increase of intensive management time (P0.05). MBC and MBN reached the maximum at 20 years in intensive management, followed by a decreasing trend. (2) the CO_2 emission flux in the soil of Lei bamboo forests showed a significant seasonal change, namely, high in spring and summer, autumn and winter. Low season. Intensive management for 1 years, 5 years, 10 years, 20 years and 30 years of bamboo forest soil CO_2 annual discharge flux were 338.89337.53374.52491.10 and 364.14 mg. CO_2. M-2. H-1, reaching the maximum value at 20 years, followed by the decreasing trend.1 years, 5 years, 10 and 30 years, there was no significant difference between the cumulative emission of the soil of the bamboo forest soil in the year of 10 and 30. The battalion significantly increased the cumulative CO_2 annual CO_2 emission (P0.05) of the soil of the bamboo forest soil. There was a significant correlation between the CO_2 emission flux and the underground 5cm soil temperature (P0.01). In addition to the intensive management of the bamboo forest for 20 years, the soil CO_2 emission flux in the remaining intensive management years was significantly positively correlated with WSOC (P0.05). There is no correlation between MBC and soil water content. (3) the N_2O emission flux in soil of Lei bamboo forest has obvious seasonal changes, namely, high in spring and summer, low in autumn and winter, intensive management for 1 years, 5 years, 10 years, 20 years and 30 years in Lei Zhulin soil, respectively: 54.10155.19202.34246.53 and 315.17 mu g. N_2O. M-2. H-1. The cumulative N_2O annual emission (P0.05) of the soil of Lei bamboo forest was increased. The concrete performance was as follows: intensive management for 5 years, 10 years, 20 years and 30 years of bamboo forest soil N_2O cumulative emissions were 1 years 3.07,3.48,4.00 and 5.74 times respectively. Intensive management for 10 years, 20 and 30 years of bamboo forest soil N_2O flux and underground 5cm soil temperature has significant correlation (P0.05). Intensive management for 5 years, 10 years and 30 years of bamboo forest soil N_2O emission flux and soil WSON has significant correlation (P0.05). Intensive management for 10 years and 30 years of soil N_2O emission flux and soil NH_4+-N has significant correlation (P0.05). Soil water content, MBN, NO3--N and soil N_2O emission flux has no correlation. (4) CH_4 emission flux in the soil of Lei bamboo forest did not There were obvious seasonal changes; intensive management significantly increased soil CH_4 cumulative emission (P0.05) and changed soil from CH_4 absorption sink to CH_4 source. Intensive management for 1 years, 5 years, 10 years, 20 years and 30 years of Lei Zhulin soil cumulative emission were respectively -0.05,2.89,3.28,6.22 and 0.80 kg. CH_4. Hm-2 a-1. for 5 year soil CH. _4 emission flux has significant correlation with soil temperature of 5 cm underground (P0.05). There is no correlation between soil CH_4 emission flux and soil temperature in 5 cm soil layer in other intensive years. There is no correlation between soil CH_4 emission and soil water content, WSOC, MBC. (5) intensive operation for 1 years, 5 years, 10 years, 20 and 30 years of bamboo forest soil emission temperature. The overall effects of the integrated greenhouse gases are: 30.15,33.99,37.19,45.52 and 39.18 Mg. CO_2-e. Hm-2. A-1., which significantly increased the comprehensive greenhouse effect of the greenhouse gases emitted from the soil of the bamboo forest. With the increase of intensive management time, the greenhouse effect of the greenhouse gases from the bamboo forest soil increased gradually (P0.05) and in intensive management. The maximum was reached in 20 years, followed by a downward trend.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S795;S714

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