间伐对杉木人工林根际土壤微生物生物量的影响毕业论文_生态学毕业论文

间伐对杉木人工林根际土壤微生物生物量的影响毕业论文

2021-04-27更新

摘 要

本文以南京溧水区林场实施了11年间伐(2008年开始间伐)的31年生的杉木Cunninghamialanceolata人工林为对象,研究了不同间伐强度(强度间伐70%、中度间伐50%、弱度间伐30%、对照0%)下的根际和非根际土壤,探讨了微生物生物量在不同间伐强度下的变化机理,旨在明晰间伐对杉木人工林根际微生物生物量的影响程度,主要成果如下:

(1)中度间伐显著增加了根际微生物生物量碳、氮的含量,根际土壤含水量、全氮、可溶性有机碳、微生物生物量碳、氮含量在各间伐强度下表现均为:中度间伐>强度间伐>对照组>弱度间伐。

(2)pH值和土壤含水量与微生物生物量碳氮之间具有一定的相关性(Plt;0.1),全氮、可溶性有机碳与微生物生物量碳氮之间具有的正相关性(Plt;0.05),全磷、全钾、土壤总有机碳、速效氮与微生物生物量碳氮无相关特性。

(3)实验中根际土壤中不同形态的碳素和氮素及全磷和全钾含量都高于非根际土壤,表现出明显的正向根际效应,同时发现根际效应还能引起指标的敏感性变化,土壤可溶性有机碳和全氮在中度间伐根际土壤中全氮的含量提升量远高于非根际土壤中的。

综上所述,中度间伐能够显著提升杉木人工林微生物生物量,有利于促进土壤养分循环,可将其作为间伐强度的参考指标。

关键词:间伐强度;杉木人工林;根际微生物生物量碳、氮;根际效应

Effects of thinning on rhizosphere microbial biomass in Chinese fir plantations

ABSTRACT

Thinning is an important and widely-used silvicultural treatment to primarily improve remaining tree growth stand regeneration. Soil microbes, as an integral part of underground ecological processes, play an important role in the nutrient cycling of forest ecosystems. Therefore, the structure and function of the aboveground and underground parts of the forest were analyzed, and the effects of thinning on the microbial biomass of rhizosphere soil of Chinese fir plantation were studied to provide a reference for the sustainable management and scientific management of Chinese fir plantation. In this study, a 31-year-old Chinese fir plantation with 11 years of thinning was carried out in Nanjing Lishui Forestry Farm. The different thinning intensity (70% intensity of strong thinning, 50% in moderate thinning, 30% in weak thinning, and 0% in control group) were sampled. The rhizosphere and non-rhizosphere soils explore the regulation mechanism of thinning on rhizosphere microbial biomass and related factors. The main conclusions are as follows:

(1)Moderate thinning significantly increased the carbon and nitrogen contents of rhizosphere microbial biomass. The rhizosphere soil water content, total nitrogen, soluble organic carbon, microbial biomass carbon and nitrogen content were all under the thinning intensity: Moderate thinninggt;Strength thinninggt;Control groupgt;Weak thinning.

(2)There is a significant positive correlation between microbial biomass carbon and microbial biomass nitrogen. And similar to pH and soil water content. Total nitrogen, soluble organic carbon and microbial biomass There is a positive correlation between microbial biomass carbon and Total nitrogen, soluble organic carbon, and there is no correlation between total phosphorus, total potassium, soil total organic carbon, available nitrogen and microbial biomass carbon and nitrogen.

(3)Different forms of carbon and nitrogen and total phosphorus and total potassium in rhizosphere soil were higher than non-rhizosphere soil, showing obvious positive rhizosphere effect, and found that rhizosphere effect can also cause indicators. The change in sensitivity, soil soluble organic carbon and total nitrogen in the intermediate thinning rhizosphere soil increased the amount of total nitrogen is much higher than in non-rhizosphere soil.

In summary, moderate thinning can significantly increase the microbial biomass of Chinese fir plantation,be conducive to the promotion of soil nutrient cycling, be used as a reference indicator of thinning intensity.

Key words:Thinning;Chinese fir plantation;Rhizosphere microbial biomass;Rhizosphere effect

目录

1、选题根据及目的意义 1

2、国内外研究进展 3

2.1 土壤及土壤微生物研究现状 3

2.1.1 土壤微生物生物量的研究方法 3

2.1.2 土壤微生物活性的研究 3

2.1.3 土壤微生物生态学研究现状 3

2.2 间伐的研究现状 4

2.2.1 间伐对森林生态系统地上部分的影响 4

2.2.2 间伐对于细根的影响 4

2.2.3 间伐对于微生物量的影响 4

3、 研究区概况及研究方法 5

3.1 研究区概况 5

3.1.1 地理位置及地质地貌 5

3.1.2 气候 5

3.1.3 土壤指标 5

3.1.4 植被条件 5

3.2 样地设置 5

3.2.1 样地选取 5

3.3 样品采集 6

3.3.1 样品采集 6

3.4 研究方法 6

3.4.1 土壤含水率测定 6

3.4.2 土壤pH测定 7

3.4.3 土壤有机碳及全氮含量测定 7

3.4.4 土壤全磷含量测定 7

3.4.4 土壤速效氮含量测定 7

3.4.5 土壤可溶性有机碳含量测定 7

3.4.6 微生物生物量碳与微生物生物量氮含量测定 8

3.5 数据处理 8

3.5.1 数据处理方法 8

3.6 技术路线 9

4、 研究结果 10

4.1 间伐对微生物生物量及不同形态碳氮的影响 10

4.1.1 间伐对杉木人工林土壤含水量及土壤酸碱度的影响 10

4.1.2 间伐对杉木人工林土壤不同形态碳氮及全磷全钾的影响 11

4.1.3 间伐对杉木人工林土壤微生物生物量碳氮比的影响 18

4.2 微生物生物量碳氮与土壤理化指标相关性分析 19

4.2.1 微生物生物量碳氮与各理化指标之间之间相关性 19

5、 讨论、结论与展望 21

5.1 讨论 21

5.1.1 间伐对土壤不同形态氮及微生物生物量氮含量影响 21

5.1.2 间伐对土壤不同形态碳及微生物生物量碳含量影响 22

5.1.3 间伐对土壤理化指标和微生物生物量碳氮比影响 22

5.2 结论 23

5.3 问题与展望 24

致谢 25

参考文献 26

1、选题根据及目的意义

间伐是一种人为调控林分密度的森林经营技术,能够改善林内环境,能够以影响土壤养分转化、控制酶活性等方式调整森林生态系统的结构和功能。Bolat等发现,间伐可以提升土壤温度、土壤有机碳含量、土壤微生物生物量碳氮,同时会降低土壤湿度,土壤有机碳含量也会影响土壤微生物生物量碳氮的含量[1],间伐措施会作用于土壤微生物,也能够改善土层环境;同时,也有研究发现,间伐的作用效果和间伐措施的强度有直接关联[2],弱度间伐在对马尾松细根生物量的影响在春夏两季有显著效果,中度间伐能够在四季都起到显著作用,然而强度间伐却只能在春季起到明显效果。

根际是植物根系与微生物活动的缓冲区域,该区域受根系与微生物活性影响强烈,根际环境能够从植物根系的分泌物和掉落物攫取土壤微生物生命活动所需、易于其转化的含碳氮的有机物,改变土壤的根际营养环境,提高根际微生物数量及活性。所以,根际土壤在森林生态系统的生态化学循环方面具有重要意义。

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