冀北山区华北落叶松人土林土壤酸碱度与养分含量的变化

发布时间：2018-05-19 10:24

本文选题：落叶松人工林 + 天然杨桦次生林　；参考：《河北农业大学》2015年硕士论文

【摘要】：华北落叶松是冀北山区的主要造林树种,华北落叶松人工林在木材生产、防风固沙、涵养水源、保持水土等方面发挥着重要的作用。冀北山地土壤理化性质的变化将会直接影响到该地区人工林的经营状况及木材产量。近年来,一些学者通过定位观测发现,一些地区部分树种的人工林存在明显的土壤酸化和地力下降的趋势。森林对土壤的影响与当地的气候及地形等生态因素密切相关。冀北山地华北落叶松林的土壤性质是否也存在明显的酸化及肥力下降的问题目前尚缺乏系统的研究。本研究以塞罕坝林区不同林龄阶段的天然杨桦次生林(10年、20年、30年、40年)及华北落叶松人工林(10年、20年、30年、40年、二代10年)作为研究对象,分析并比较两种不同林分类型、不同林分年龄之间土壤p H值、阳离子交换量、盐基饱和度、土壤有机质含量及土壤中主要养分元素的含量的区别及演变规律。森林植物凋落物的分解过程与林地土壤养分关系密切,本研究比较了华北落叶松及其主要伴生植物凋落物的分解对土壤p H值、有机质及各种养分含量的影响。主要得到如下结论:(1)林地土壤p H值低于无林地;林地土壤阳离子交换量、交换性盐基总量、盐基饱和度、土壤有机质含量、碱解氮含量、速效磷含量、全氮含量及全钾含量均高于无林地;林地土壤全磷含量略高于荒地,但相差不大;林地土壤速效钾含量与荒地相差不大。(2)两种林分相比,土壤速效磷含量、全氮含量及全钾含量表现为杨桦天然次生林高于落叶松人工林;土壤全磷含量落叶松人工林略高于天然杨桦次生林,但差别不大;土壤碱解氮含量10年生及20年生杨桦次生林高于相同林龄的落叶松人工林,30年生及40年生两种林分差别不大;土壤速效钾含量10年生杨桦林明显高于10年生落叶松林,20、30、40年生两种林分差异不大;其余各指标两种林分差别不大。(3)塞罕坝林区主要为弱酸性土壤,土壤p H值介于6.00~6.58之间;林地土壤p H值低于无林地,华北落叶松人工林土壤p H值略高于天然杨桦次生林;华北落叶松人工林林地土壤p H值随着林龄的增加总体呈下降的趋势;土壤p H值随土层深度的加深而上升;土壤阳离子交换量随土层深度的增加而降低,而与年龄没有明显的相关关系;土壤盐基饱和度与林龄与土层深度都没有明显的相关关系。该地区土壤盐基饱和度较高,酸化缓冲能力较强,但土壤p H值依然有所下降,该地区华北落叶松人工林存在土壤酸化的现象,在森林经营管理过程中应采取相应的措施加以控制,避免土壤继续酸化。(4)随着林龄的增加,华北落叶松人工林0~50cm土壤有机质含量先上升后下降,天然杨桦次生林无明显变化趋势;落叶松人工林土壤碱解氮、速效磷含量均大致呈递增趋势,速效钾含量呈下降趋势;杨桦天然次生林几种林龄土壤速效氮含量基本持平,速效磷含量没有表现出明显变化规律;土壤速效钾含量随林龄的增长表现出明显的下降趋势;随着林龄的增长,落叶松人工林土壤全氮含量大致呈增加的趋势,全磷含量无明显变化趋势,全钾含量呈下降趋势;天然杨桦次生林随林龄的增长土壤全氮、全磷含量无明显变化,全钾含量下降。(5)大体上来看,塞罕坝地区土壤主要处于中等肥力水平。然而,根据全国及华北地区土壤质量衡量标准,该地区土壤中氮、磷两种元素的含量较为匮乏,在森林的经营过程中应引起注意。(6)落叶松二代林土壤化学性质各指标除速效磷外,其余均明显低于一代林。具体表现为,落叶松二代10年生人工林0~50cm土壤p H值较一代10年生林下降0.23个单位,阳离子交换量下降44.43%,盐基饱和度下降9.59%,土壤有机质含量下降24.01%,土壤碱解氮含量下降20.27%,土壤速效磷含量上升8.09%,土壤速效钾含量下降28.88%,土壤全氮含量下降28.57%,全磷含量下降9.09%,速效钾含量下降16.76%。二代林土壤目前处于中等肥力水平,但相比一代林,下降趋势明显,因而在森林的经营管理过程中,应采取科学合理的措施,抑制土壤肥力的继续衰退。(7)草本、灌木植物凋落物分解对土壤化学性质有较大影响,针叶凋落物分解对土壤化学性质影响较小。另外,降水的淋溶作用对凋落物中养分的释放影响很小。
[Abstract]:North China Larix Larix is the main afforestation tree in the northern Hebei Province. The North China larch plantation plays an important role in wood production, wind protection and sand fixation, water conservation and conservation of water and soil. The change of soil physical and chemical properties in northern Hebei will directly affect the management and timber production of artificial forests in this area. In recent years, some scholars have done the same. It is found that there is an obvious trend of soil acidification and soil fertility decline in some tree species in some regions. The influence of forest on soil is closely related to the local climate and topography. In this study, the natural poplar secondary forest (10 years, 20 years, 30 years, 40 years) and North China larch plantation (10 years, 20 years, 30 years, 40 years, two generation 10 years) were used in this study to analyze and compare the P H value, cation exchange amount and salt of the soil between the two different forest types and the different stand age. The difference and evolution law of basic saturation, soil organic matter content and the content of main nutrient elements in soil. The decomposition process of forest litter is closely related to the soil nutrient of woodland. This study compared the influence of the decomposition of Larch and its main associated plant litter on P H value, organic matter and the content of various nutrients in the soil. The main conclusions are as follows: (1) the value of P H in woodland soil is lower than that of no forestland; the amount of soil cation exchange, the total amount of exchangeable salt, the saturation of salt base, the content of soil organic matter, the content of alkaline nitrogen, the content of available phosphorus, the total nitrogen content and total potassium content are higher than that of the non forestland; the total phosphorus content in the woodland is slightly higher than that in the wasteland, but the difference is not significant; the forest soil soil is small. There was little difference between the content of available K and the wasteland. (2) the content of available P, total N and total K in the two species were higher than that of larch plantation; the total P content of Larix Larix was slightly higher than that of the natural birch secondary forest, but the difference was not great; the soil alkaline nitrogen content was 10 and 20 Yang Hua secondary. Forest height is higher than the same forest age of Larix Larix artificial forest, 30 years and 40 years of two kinds of forest difference is not significant; the soil available potassium content of 10 year Yang Hualin is significantly higher than the 10 year old larch forest, 20,30,40 year two stand difference is not significant; the rest of the index two kinds of stand difference is not small. (3) the sluhan dam forest area is mainly weak acid soil, soil P H value is 6. Between.00~6.58, the value of P H in woodland soil was lower than that of no woodland, and the value of P H in the soil of North China larch plantation was slightly higher than that of natural birch secondary forest; the P H value of soil soil in North China Larix plantations decreased with the increase of forest age, and the H value of soil P increased with the depth of soil layer, and the soil cation exchange amount increased with the depth of soil layer. There is no obvious correlation between age and age. There is no obvious correlation between soil salt base saturation and soil depth. The soil salt base saturation is high, and the acidification buffer ability is strong, but the P H value of soil is still declining. The soil acidification of the North China larch plantation is the phenomenon of soil acidification and the forest management in this area. In the process of management, the corresponding measures should be taken to avoid the continuous acidification of soil. (4) with the increase of forest age, the content of soil organic matter in the 0~50cm soil of the North China larch plantation increased first and then decreased, and there was no obvious change trend in the natural poplar secondary forest. The content of soil available nitrogen in the natural secondary forest of poplar and birch was basically flat, and the content of available P did not show obvious change. The content of soil available potassium showed a obvious decreasing trend with the growth of forest age. With the growth of forest age, the total nitrogen content in soil of Larix Larix artificial forests increased roughly, and total phosphorus was increased. The content of total potassium showed a decline trend, the content of total potassium in natural poplar secondary forest increased with the growth of soil total N, total P content had no obvious change, total potassium content decreased. (5) in general, the soil in the sahhan dam area was mainly in the middle fertility level. The content of two elements of nitrogen and phosphorus in the soil is scarce and should be paid attention to in the process of forest management. (6) the chemical properties of the soil of the two generation of Larch two generation forest are obviously lower than that of the one generation forest. The specific performance is that the P H value of the two generation plantation of Larch 10 year old plantation is 0.23 units lower than that of the one generation 10 year forest. The sub exchange rate decreased 44.43%, the salt base saturation decreased by 9.59%, the soil organic matter content decreased by 24.01%, the soil alkali hydrolysable nitrogen content decreased 20.27%, the soil available phosphorus content increased 8.09%, the soil quick available potassium content decreased 28.88%, the soil total nitrogen content dropped 28.57%, the total phosphorus content decreased 9.09%, the available potassium content decreased by 16.76%. two generation soil at present in the soil at present in the soil of the generation forest soil at present in the soil at present in the soil at 16.76%. two generation soil at two generation soil now in the soil soil soil soil at present. In the course of forest management, scientific and reasonable measures should be taken to restrain the continued decline of soil fertility. (7) the litter decomposition of shrubs has a great influence on the chemical properties of soil, and the decomposition of coniferous litter has little influence on the chemical properties of soil. The leaching of precipitation has little effect on the release of nutrients in litters.
【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714

【参考文献】