格氏栲天然林林窗凋落物与土壤的生态化学计量特征研究

发布时间：2018-06-09 05:18

本文选题：生态化学计量特征 + 林窗　；参考：《福建农林大学》2017年硕士论文

【摘要】：格氏栲(Castanopsis kawakamii Hayata)属珍稀濒危植物,自然分布狭窄,三明小湖区有近700 hm2呈纯林状态的格氏栲天然林实属罕见。由于人为破坏、自身生物学特性及自然环境等因素综合作用,格氏栲资源已趋于枯竭。目前,格氏栲林林窗数量增多,格氏栲种群数量下降,幼苗更新困难,如何促进格氏栲更新已成为当务之急。而林窗大小会影响凋落物难分解物质、凋落物养分与土壤养分等,为研究格氏栲更新问题提供了契机,同时,生态化学计量特征主要研究生态过程中化学元素的比例关系,为研究凋落物与土壤化学元素的耦合关系提供了一种综合方法。因此,将林窗分为大(150 m2)、中(50～100 m2)、小(30～50m2),并在林窗内设置不同方位,研究凋落物难易分解物质与土壤生态化学计量特征,以期深入了解林窗凋落物和土壤养分分布格局,揭示凋落物和土壤生态化学计量特征的关系,探讨样养分循环规律,为格氏栲人工栽培和土壤肥力管理提供参考。结果表明:(1)林窗大小对凋落物碳(C)、氮(N)、磷(P)、钾(K)生态化学计量特征具有显著性影响。大林窗凋落物C、N含量显著高于中、小林窗;小林窗P、K含量显著高于大、中林窗。大、中林窗凋落物C:N、C:P和N:P显著高于小林窗,大林窗C:K、N:K显著高于中、小林窗,小林窗凋落物P:K显著高于大、中林窗。林窗和非林窗不同方位的凋落物养分含量高值区分布规律不明显,其生态化学计量特征低值区多分布于林窗中央。由于N:P较低会加速凋落物分解,中、小林窗和林窗中央凋落物分解较快,增加了土壤肥力,促进地下土壤生态系统养分循环。(2)在乙醇浓度为70%,提取温度为80℃,乙醇-水溶液体积为15mL的条件下,单宁提取效果最佳,提取含量为30.58 g.kg-1。大林窗纤维素、木质素、单宁、总酚含量显著高于中、小林窗。林窗凋落物难分解物质多集中于西(W)方向,而林窗中央(O方向)含量较低。非林窗凋落物难分解物质多集中于西北(NW)方向,而北(N)方向含量较低。因此,林窗中央和非林窗北(N)方向难分解物质含量较低,具有较大的养分供给潜力。同时,可采取适当措施促进林窗西(W)方向和非林窗西北(NW)方向的难分解物质降解,维持林地内养分平衡。.(3)大林窗土壤全碳(C)、全氮(N)、全磷(P)、全钾(K)含量和C:N显著高于中、小林窗。小林窗土壤C:P、C:K、N:P、N:.K与P:K均显著高于大、中林窗。林窗和非林窗内C和N含量的高值区多为东南(SE)方向,而林窗中央(O方向)土壤P和K含量较高。C:P与N:P变化趋势相似,低值区多为林窗中央(O方向);C:K与N:K变化趋势相似,多表现为不同方位间差异不明显。因此,大、中林窗和林窗中央土壤肥力较高,为植物生长提供较高的养分供给潜力。(4)凋落物难易分解物质与土壤生态化学计量特征的pearson相关性分析与冗余分析(RDA)的结果表明:大林窗内凋落物纤维素、单宁含量与土壤C、N含量呈显著正相关关系。大、中林窗凋落物C:P、N:P与土壤P、K含量呈显著正相关关系,与土壤C:P、C:K、N:P和N:K多呈显著负相关关系。林窗不同方位上,凋落物C、单宁、总酚含量与土壤C、N、P、K呈显著正相关,与C:N、C:P、C:K、N:P、N:K、P:K呈显著负相关关系,尤其林窗中央表现更加明显。因此,大、中林窗和林窗中央难分解物质含量低,凋落物分解较快,土壤肥力高,为植物生长发育提供了适宜场所。
[Abstract]:Castanopsis kawakamii Hayata (Castanopsis kankam) is a rare and endangered plant with narrow natural distribution. The natural forest of Castanopsis kankam is rare in the small lake area of Sanming, which has nearly 700 hm2 in pure forest. The resources of Castanopsis fargesii have become exhausted because of human destruction, its biological characteristics and natural environment, and the number of Castanopsis Castanopsis forest windows is increasing. In addition, the population of Castanopsis kankam declined and the seedling regeneration was difficult. How to promote the regeneration of Castanopsis kankam has become an urgent matter. The size of the forest window will affect the litter decomposition material, litter nutrient and soil nutrients, which provide an opportunity to study the problem of the regeneration of Castanopsis kankam. At the same time, the biological stoichiometric characteristics mainly study the chemical elements in the ecological process. The proportion relationship provides a comprehensive method for studying the coupling relationship between litter and soil chemical elements. Therefore, the forest windows are divided into large (150 m2), medium (50~100 m2), small (30 to 50m2), and different azimuths are set in the forest windows to study the characteristics of the litter's difficult and easy to decompose material and the Soil Eco chemical measurement, in order to understand the litter fall in depth. The distribution pattern of soil nutrients revealed the relationship between litter and Soil Eco chemical measurement characteristics, explored the regularity of nutrient cycling, and provided reference for the artificial cultivation of Castanopsis kamkamii and soil fertility management. The results showed that: (1) the forest window size had significant influence on the ecological chemical measurement characteristics of litter carbon (C), nitrogen (N), phosphorus (P), and potassium (K). The Dalin window withered The contents of C and N were significantly higher than that in the middle window; the P, the K content of the forest window was significantly higher than that of the large, medium window, middle forest window litter, C:N, C:P and N:P significantly higher than the small forest window, the Dalin window C:K, and the N:K significantly higher than the middle, the small forest window and the small forest window litter P:K significantly higher than the large, middle forest window. The high value distinction of the litter nutrient content in the different directions of forest windows and non forest windows The low value area of its eco chemical measurement characteristics is mostly distributed in the middle of the forest window. Because the low N:P will accelerate the decomposition of litter, the litter decomposition in the middle of the forest window and the central forest window is fast decomposed, the soil fertility is increased and the nutrient cycling in the underground soil ecosystem is promoted. (2) the ethanol concentration is 70%, the extraction temperature is 80, ethanol water solution. Under the condition of 15mL, the extraction effect of tannin was the best, the extraction content was 30.58 g.kg-1. Dalin window cellulose, the lignin, tannin and total phenol content was significantly higher than that in the forest window. The refractory material in the forest window litter was mostly concentrated in the West (W) direction, but the content of the central (O direction) in the forest window was lower. The non forest window litter decomposition material was mostly concentrated in the Northwest (NW ) in the direction, the North (N) direction is low. Therefore, the hard decomposable material content in the central and the North (N) direction of the forest window is lower and has a great potential for nutrient supply. At the same time, appropriate measures can be taken to promote the degradation of the refractory material in the direction of West (W) and the Northwest (NW) of the forest window, and maintain the nutrient balance in the woodland. (3) the whole carbon of the Dalin window soil. (C), total nitrogen (N), total phosphorus (P), total potassium (K) content and C:N were significantly higher than that in the middle, small forest windows, C:P, C:K, N:P, N:.K and P:K were significantly higher than the large, middle forest window. The high value area of C and N content in the forest window and the non forest windows is more than the southeast. In the middle of the window (O direction), the change trend of C:K and N:K was similar, and the difference between different azimuth was not obvious. Therefore, the high fertility of the middle forest window and the central forest window was higher, and the high nutrient supply potential for the plant growth. (4) the Pearson correlation analysis and redundancy analysis of the litter and soil biostoichiometric characteristics were analyzed and analyzed (RD The results of A) showed that the content of tannin in the Dalin window had a significant positive correlation with the content of C and N in soil. Large, medium window litter C:P, N:P and soil P, K content had a significant positive correlation with soil C:P, C:K, N:P and N:K in soil, and litter C, tannin, total phenol content and soil There was a significant positive correlation with C:N, C:P, C:K, N:P, N:K, P:K, especially in the middle of the forest window, especially in the middle of the forest window. Therefore, the medium in the middle and forest windows had a low decomposition material content, the litter decomposition was faster and the soil fertility was high, which provided the suitable place for the plant growth and development.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714

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