不同森林经营模式对深层土壤氮素的影响毕业论文_生态学毕业论文

不同森林经营模式对深层土壤氮素的影响毕业论文

2021-04-27更新

摘 要

氮素不仅是土壤肥力的重要表征,同时也是影响植物生长发育的关键因素,在森林生态系统养分循环中起到重要作用。土壤深层氮素若由于不当的森林经营模式而挥发、淋溶、流失,不仅会造成肥料,能源的浪费,还会对环境产生污染,氮经径流和淋溶进入水体,将会加重水体富营养化,造成地下水污染并危机人类健康。所以将不同森林经营模式下深层土壤氮素的各项指标进行统筹分析,研究不同经营模式对深层土壤氮素的影响,旨在为杨树人工林的可持续经营及科学管理提供参考依据。本研究以江苏省宜兴市周铁镇沙塘港村2009年1月份营造的杨树人工林为对象,研究了不同森林经营模式(杨树纯林,杨树-红叶石楠混交林,杨树-大叶女贞混交林)下的深层土壤,旨在明晰不同森林经营模式对深层土壤的硝态氮,铵态氮,总氮,含水率以及它们之间的相关性造成的影响。主要结果如下。

(1)与杨树纯林相比深层土壤铵态氮与总氮含量都会随混交林模式而增加,如杨树×大叶女贞混交林中深层土壤铵态氮含量显著增加,而杨树×红叶石楠混交林中深层土壤总氮含量显著增加,混交林经营模式对深层土壤铵态氮和深层土壤总氮含量有显著影响。杨树×红叶石楠混交林中深层土壤硝态氮含量显著降低。

(2)杨树×大叶女贞与杨树×红叶石楠经营模式对深层土壤含水率无明显影响,通过单因素方差分析,更佐证了这个结论,

(3)相关性方面,深层土壤硝态氮与深层土壤总氮含量呈显著负相关。深层土壤硝态氮与深层土壤含水率呈显著负相关。深层土壤铵态氮含量与深层土壤含水率不相关,深层土壤铵态氮含量与深层土壤总氮含量不相关,深层土壤铵态氮含量与深层土壤硝态氮含量不相关,深层土壤总氮含量与深层土壤含水率不相关。

综上所述,采用杨树与红叶石楠或大叶女贞混交的经营模式能显著提升深层土壤铵态氮含量与总氮含量,有利于促进土壤养分循环,可将其作为森林经营模式的选择参考。

关键词:杨树人工林,森林经营模式,深层土壤氮素

Effects of different forest management models on nitrogen in deep soil

ABSTRACT

Nitrogen is not only an important indicator of soil fertility, but also a key factor affecting plant growth and development, and plays an important role in the nutrient cycle of forest ecosystem. If the soil deep nitrogen volatilizes, leaches and loses due to improper forest management mode, it will not only cause waste of fertilizer and energy, but also cause environmental pollution. When nitrogen enters water body through runoff and leached, it will aggravate water eutrophication, cause groundwater pollution and endanger human health. Therefore, various indexes of deep soil nitrogen under different forest management modes were comprehensively analyzed to study the effects of different management modes on deep soil nitrogen, so as to provide reference for the sustainable management and scientific management of poplar plantation. This study in Yixing city of Jiangsu province ZhouTie Town sand pond village of port construction of poplar plantation in January 2009, as the object, studies the different forest management mode (pure forest of poplar, poplar – photinia x mixed forest, poplar – big leaf privet mixed) under the deep soil, aims to clarify different forest management model of deep soil no3 — n, ammonium nitrogen, total nitrogen, the effects of moisture content and the correlation between them. The main results are as follows.

(1) Compared with pure forest of poplar deep soil ammonium nitrogen and total nitrogen content increases with mixed mode, such as poplar x big leaf privet deep soil ammonium nitrogen content in the mixed forest increased significantly, and poplar x photinia x deep soil total nitrogen content increased significantly in the mixed forest, mixed forest management pattern of deep soil ammonium nitrogen and deep has remarkable effect on soil total nitrogen content.

(2) Poplar × privet and poplar × photinia have no significant impact on the nitrate nitrogen content and water content of deep soil. This conclusion is further supported by one-way analysis of variance.

(3) In terms of correlation, there was a significant negative correlation between nitrate nitrogen in deep soil and total nitrogen content in deep soil. There was a significant negative correlation between nitrate nitrogen and water content in deep soil. The content of ammonium nitrogen in deep soil is not correlated with the content of water content in deep soil, the content of ammonium nitrogen in deep soil is not correlated with the content of nitrate nitrogen in deep soil, and the content of total nitrogen in deep soil is not correlated with the content of water content in deep soil.

In conclusion, the mixed management mode of poplar with red heather or privet major can significantly increase the ammonium nitrogen content and total nitrogen content in deep soil, which is conducive to promoting soil nutrient cycle, and can be used as a reference for forest management mode selection.

Key words:Poplar plantation;Forest management model;Deep soil nitrogen

目录

1 研究背景 1 –

2 国内外研究进展 2 –

2.1土壤氮素及其转化 2 –

2.1.1土壤氮素 2 –

2.1.2深层土壤氮素的转化 2 –

2.2不同因素对深层土壤氮素的影响 2 –

2.2.1施肥模式对深层土壤氮素的影响 2 –

2.2.2植物及其经营模式对深层土壤氮素的影响 3 –

3 研究区概况及研究方法 6 –

3.1研究区概况 6 –

3.1.1地理位置 6 –

3.1.2气候 6 –

3.1.3土壤指标 6 –

3.1.4降雨 6 –

3.2样地设置 6 –

3.2.1样地选取 6 –

3.3样品采集 7 –

3.3.1样品采集 7 –

3.4研究方法 7 –

3.4.1土壤含水率测定 7 –

3.4.2土壤总氮测定 7 –

3.4.3土壤硝态氮测定 8 –

3.4.4土壤铵态氮测定 8 –

3.5数据处理 9 –

3.5.1数据处理方法 9 –

3.6技术路线 10 –

4 研究结果 11 –

4.1不同森林经营模式对深层土壤各指标的影响 11 –

4.1.1不同森林经营模式对深层土壤含水率的影响 11 –

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