中国北方草地土壤非晶态硅形态研究

发布时间：2018-10-23 07:09

【摘要】：草地生态系统是我国面积最大的陆地生态系统,也是遭受人类生产生活影响最严重的陆地生态系统之一。草地沙化不仅对生态环境造成恶劣后果,而且对经济发展也会带来负面影响。硅元素作为地壳中丰度仅次于氧的第二大元素,不仅对调节植物的生长发育具有重要的意义,而且对维持生态系统的稳定性具有重要的作用。本研究以中国北方不同类型草地、不同沙化程度草地以及草地—草地造林地为研究对象,采用逐级化学提取方法和紫外可见分光光度法提取并测量土壤中酸可溶态硅、可氧化态硅、铁锰氧化物结合态硅以及无定形态硅这四种非晶态硅的含量,探析草地类型、沙化程度以及退草还林对土壤非晶态硅的含量、分布和形态组分的影响,论述草地土壤硅的生物地球化学循环的规律,为研究草地生态系统修复和实现草地资源可持续利用提供一定的参考。(1)对典型草原、草甸草原和草甸三种不同类型草地土壤中非晶态硅的研究发现:我国北方草地酸可溶态硅含量的变化范围为111.09~465.51 mg kg-1,可氧化态硅含量的变化范围为129.21~358.85 mg kg-1,铁锰氧化物结合态硅的含量变化范围为145.5~568.02 mg kg-1,无定形硅的含量变化范围为1171.73~4503.91mg kg-1;在不同深度的土壤中,典型草原的酸可溶态硅、锰氧化物结合态硅和无定形硅的含量均显著(p0.05)高于草甸草原和草甸,可氧化态硅含量也呈现出相似的趋势。研究结果表明,不同草地类型对草地土壤非晶态硅的含量、空间分布及组分都具有显著的影响。(2)对未沙化、轻度沙化、中度沙化和重度沙化四种不同沙化程度草地土壤中非晶态硅的研究发现:我国北方沙化草地的酸可溶态硅含量的变化范围是93.16~138.64 mg kg-1,可氧化态硅含量的变化范围是46.23~101.96 mg kg-1,铁锰氧化物结合态硅含量的变化范围是53.64~110.31 mg kg-1,无定形硅含量的变化范围是570.47~1226.46 mg kg-1;未沙化草地的酸可溶态硅在0-10 cm和10-30cm深度的土壤中均显著(p0.05)低于重度沙化草地(在30-50 cm深度的土壤出也呈现类似的趋势),未沙化草地的可氧化态硅、铁锰氧化物结合态硅以及无定形硅在不同深度土壤中的含量均显著(p0.05)高于重度沙化草地。研究结果表明,草地沙化对草地土壤的硅形态有着较大的影响并且沙化程度的加剧会使得非晶态硅中的其他形态硅向酸可溶态硅转化。(3)对比造林土壤与草地土壤中非晶态硅的研究发现:草地和林地酸可溶态硅含量的变化范围分别是161.92~337.76 mg kg-1和82.50~134.67 mg kg-1,可氧化态硅含量的变化范围分别是213.58~334.95 mg kg-1和192.85~231.50 mg kg-1,铁锰氧化物结合态硅的含量变化范围分别是285.01~332.88 mg kg-1和204.27~213.37 mg kg-1,无定形硅的含量变化范围分别是1946.47~2763.08 mg kg-1和1497.80~1630.30 mg kg-1;在草地—草地造林地,四种非晶态硅在草地表层土壤(0-10 cm)中的含量均显著(p0.05)高于其在林地表层土壤中的含量,在其他深度土壤中也呈现相似的变化趋势。研究结果表明,造林对草地土壤硅形态有影响且造林会弱化其他形态的非晶态硅向酸可溶态硅转化。
[Abstract]:Grassland ecosystem is the largest land ecosystem in China, and it is one of the most serious land ecosystems affected by human production. Grassland desertification not only has adverse consequences on the ecological environment, but also has a negative impact on economic development. As the second largest element in the crust, the silicon element is only the second largest element in the crust, which not only plays an important role in regulating the growth and development of the plant, but also plays an important role in maintaining the stability of the ecosystem. In this study, different types of grassland, different desertification degree grass and grassland grassland were planted as research objects in northern China, and the acid-soluble silicon and oxidizable silicon in soil were extracted and measured by stepwise chemical extraction and UV-visible spectrophotometry. The contents of four kinds of amorphous silicon, such as the type of the grassland, the degree of desertification and the influence of the return grass forest on the contents, distribution and morphological components of the amorphous silicon in the soil are analyzed, and the law of biogeochemical cycling of the soil silicon in grassland is discussed. In order to study grassland ecosystem restoration and realize the sustainable utilization of grassland resources, a certain reference is provided. (1) The study of amorphous silicon in three different grassland soils of grassland, meadow steppe and meadow showed that the content of soluble silicon in grassland acid in northern China ranges from 111. 09-465. 51 mg kg-1, and the change of the content of oxidizable silicon is 129. 21-358. 85 mg kg-1. The content of Fe-Mn oxide was 145. 5-568. 02 mg kg-1, and the content of amorphous silicon was 1171. 73-4503. 014mg kg-1. In soil of different depths, the content of acid-soluble silicon, manganese oxide and amorphous silicon in typical steppe were significantly higher than that of meadow steppe and meadow. the content of oxidizable silicon also exhibits similar trends. The results showed that different grassland types had significant influence on the content, spatial distribution and composition of amorphous silicon in grassland soil. (2) The study of the amorphous silicon in the soil of four different desertification degrees of non-desertification, mild desertification, moderate desertification and severe desertification shows that the variation range of the acid-soluble silicon content of the desertification grassland in the north of China is 93. 16-138. 64 mg kg-1, and the change range of the oxidizable silicon content is 46. 23-101. 96mg kg-1. The content of Fe-Mn oxide was 53. 64-110. 31 mg kg-1, and the range of amorphous silicon content was 570. 47-1.46 mg kg-1. The acid-soluble silicon of the undesertified grassland was significantly higher in the 0-10 cm and 10-30cm depth soil (P0.05). The content of iron-manganese oxide glassy silicon and amorphous silicon in different depth soil was significantly higher than that of severe desertification grassland. The results show that grassland desertification has a great influence on the silicon morphology of grassland soil, and the intensification of desertification degree can cause other forms of silicon in amorphous silicon to convert to acid-soluble silicon. (3) Compared with the study of non-crystalline silicon in soil and grassland soil, the changes of soluble silicon content in grassland and forest land were 161. 92 ~ 337. 76 mg kg -1 and 82. 50 ~ 134. 67 mg kg -1, and the change range of oxidizable silicon content was 213. 58 ~ 334. 95 mg kg -1 and 192. 85 ~ 231. 50 mg kg -1, respectively. The contents of iron-manganese oxide were 285.01-332. 88mg kg-1 and 204.27-213. 37mg kg-1 respectively. The range of the contents of amorphous silicon was 1946. 47-2763. 08 mg kg-1 and 1497. 80-1630. 30 mg kg-1 respectively. The contents of four kinds of amorphous silicon in surface soil (0-10 cm) of grassland were significantly higher than those in the surface soil of forest land, and similar trends were also presented in other depth soil. The results showed that the effect of afforestation on the morphology of soil silicon in grassland and the transformation of non-crystalline silicon to acid-soluble silicon in other forms could be weakened.
【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】：S812.2

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