不同林龄杉木人工林土壤理化性质变化毕业论文_林学毕业论文

不同林龄杉木人工林土壤理化性质变化毕业论文

2021-04-19更新

摘 要

作为中国杉木人工林的中心区域,江西省近年来森林总储量和林业总产量方面十分突出,但杉木产业日益增长的背后却出现一系列问题,例如土壤养分下降、土壤退化等问题,使得杉木产量逐年下降。因此,为提高木材产量和为人工林管理以及可持续发展提供依据;防止出现人工林生态系统退化、土壤效力低下等问题,必须结合江西省林地特性与林业现状,有针对性的进行研究。

本文通过江西省永丰县几代官山林场和不同龄级杉木人工林为研究对象确定土壤养分和化学性质。研究结果表明:

(1)不同林龄杉木人工林土壤有效养分变化表明幼龄林相对较高,到中林龄养分含量明显下降,到成熟林又有所回升。这说明在杉木人工林生长到中林龄阶段所需养分最多,到成熟林阶段后为维持正常光合作用、呼吸作用等,所需养分就有所下降,使得土壤肥力有所上升。

(2)从整个杉木生长周期来看,磷、钾元素含量明显降低,尤其是P,其含量远低于杉木生长发育所需的临界值,长期处于缺乏状态,K元素为表现出缺乏,因此建议在生产中增加磷肥,以保证杉木的正常生长发育,提高产量。

(3)土壤pH值与总酸度在不同林龄、土层均表现出及显著差异,且随着杉木生长,土壤的酸性也越来越强。结果表明,杉木的年龄越大,对土壤性质的影响越强。

关键字:杉木人工林;土壤养分;影响因素;研究方法

Changes of soil nutrients in Chinese fir plantations of different age

ABSTRACT

Jiangxi province is the center of China’s Chinese fir plantations. In recent years, the total forest volume and the total output value of the forestry are among the best in China. However, with the continuous development of Chinese fir industry, some regions have experienced the decline of soil fertility and the gradual slowing down of Chinese fir growth.Therefore, the research on the evolution of soil quality of Chinese fir plantation forest land, especially the systematic research on the characteristics of forest land and the present situation of forestry development in jiangxi province, needs to be further deepened.Therefore, the law of soil fertility evolution in Chinese fir plantation is not only conducive to the rational use of soil, the prevention of forest ecosystem degradation and the protection of ecological environment, but also provides a basis for forest soil management and sustainable development regulation.

In this paper, several generations of continuous cultivation in guanshan forest field of yongfeng county, jiangxi province and artificial pure forests of Chinese fir of different ages were taken as the research object, soil nutrients and chemical properties were determined and analyzed, and the results showed that:

(1) the change of soil available nutrients in Chinese fir plantations of different age indicated that the young forest was relatively high, and the nutrient content decreased obviously at medium age, and then increased to mature forest.This indicates that during the growth of Chinese fir plantation to medium forest age, the required nutrients are the most, and after the growth to mature forest stage, in order to maintain normal photosynthesis, respiration and so on, the required nutrients decline, making the soil fertility increase.

(2) from the point of the whole Chinese fir growth cycle, phosphorus, potassium content is significantly reduced, especially in P, its content is far lower than the threshold needed for the Chinese fir growth, in the lack of state for a long time, to show a lack of K element, it is recommended that increasing P fertilizer application in the production, to ensure the normal growth and development of Chinese fir, increase production.

(3) Soil pH value and total acidity were significantly different in different forest ages and soil layers, and the soil became more acidic with the growth of Chinese fir.This indicated that the older the cedar stand was, the stronger the effect on soil properties was.

Key words : Chinese fir plantation;Soil nutrients;Influence factor;Research technique

目录

1研究背景 – 1 –

1.1研究的目的与意义 – 1 –

2 研究进展 – 2 –

2.1杉木概述 – 2 –

2.1.1杉木的主要用途 – 2 –

2.2 杉木人工林土壤概况 – 3 –

2.2.1杉木人工林林下土壤物理性质 – 3 –

2.2.2杉木人工林土壤化学性质 – 3 –

2.3导致杉木人工林土壤效力低下原因 – 4 –

2.3.1栽植制度 – 4 –

2.3.2营林活动 – 4 –

2.3.3肥料的施用 – 5 –

3研究地概况与研究方法 – 6 –

3.1研究地概况 – 6 –

3.2研究方法 – 7 –

3.2.1样地设置以及样品采集 – 7 –

3.2.2实验项目与分析方法 – 7 –

4结果与分析 – 8 –

4.1不同林龄杉木人工林土壤全磷变化 – 8 –

4.2不同林龄杉木人工林土壤全钾变化 – 9 –

4.3不同林龄杉木人工林pH值、水解性总酸度变化 – 11 –

结论 – 14 –

致 谢 – 15 –

参考文献 – 16 –

1研究背景

1.1研究的目的与意义

早在19世纪初,中国林业人提出人工林土壤肥力衰退的相关问题,当时这种衰退现象在被称为为“第二代效应”。这是因为在种植园的栽培和栽培过程中土壤形成过程和土壤成熟过程已经发生变化,结果,土壤性质恶化,不能很好的满足林木生长需求,出现土壤理化性质退变、土壤生物多样性减少、土壤肥力下降、林分生产力降低等现象[1]。杉木(Cunninghamia lanceolata)作为我国特有的速生丰产树种,因其生长迅速和材质优良的特点深受林农的青睐[2]。但近年来,由于杉木人工林的不正确的营林措施以及为实现增产行使连载制度,使得林地土壤出现地理衰退、微生物含量降低、土壤中毒等问题,导致木材产量下降,现已严重威胁到我国杉木的生长生产[3]。因此改善杉木低效用材林是解决南方低效人工林改造问题的主要研究方面。

杉木不仅是我国南方速生及优材树种,而且森林固碳方面发挥着重要作用[4]。其优质的材料质量和快速生长的特性深受林农的青睐。近年来,长期的林业生产实践表明,由于杉木人工林自身的生物学特性以及杉木林结构单一,杉木全垦整地,炼山,纯林短期轮伐、多代栽植,生态系统结构简单,抵抗力日益降低导致土壤板结等问题,因此杉木纯林地力衰退和生产力下降现象日益突出,土壤养分含量急剧下降,土壤质量严重下降。如何改善人工林林地质量以及如何提高人工林产量成为一直困扰大家的问题。土壤理化性质是体现杉木人工林生长的重要因子;所以明确杉木人工林各年龄阶段林下土壤特性以及整体变化状况;有针对性的对不同阶段杉木人工林实施治理,以此有针对性的来提高土壤肥力,林地生产力,为杉木纯林健康持续经营提供科学的理论依据以及实践指导意义。

2 研究进展

2.1杉木概述

杉木是中国特有的,杉木的生长对温度,降水和土壤有要求。具有喜光的特点。要求年平均气温在16到19摄氏度,降水量要分布均匀且年平均降水量要达到1300到1800毫米之间,土地不仅要足够肥沃和疏松,还要求有良好的排水。另外,阴坡和连绵的山区更符合杉木的生长环境,对杉木的生长也更有利。大多数林农和投资者在营造速生丰产林时都会选择杉木作为首选树种,这是因为杉木的生长比较快,材质也较好,产生的经济效益也比较可观。选择气温、降雨量、湿度和土壤等条件适宜的地方进行杉木的栽培十分重要,土质为红粘土的丘陵和岗地较适合杉木栽培,土质为黄壤、黄红壤和黄棕土壤的山地也比较适宜杉木的生长[5]

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