兰州大学机构库 >生态学院
陇中黄土高原主要人工防护林植物-土壤互馈作用研究
Alternative TitlePlant-soil Interaction of Main Artificial Protective Forest in the Longzhong Loess Plateau
姚文秀
Subtype博士
Thesis Advisor赵长明
2023-09-02
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name理学博士
Degree Discipline生态学
Keyword陇中黄土高原 The Longzhong Loess Plateau 人工防护林 Artificial Protective Forest 植物-土壤互馈 Plant-soil interaction 土壤质量 Soil quality 土壤微生物 Soil microorganism
Abstract

植物-土壤互馈主要指植物生长改变了其生长环境中土壤的生物和非生物属性,而改变后的土壤属性再反作用于植物生长的过程,其核心是揭示植物与土壤生物和非生物环境间相互作用关系。植物-土壤互馈被广泛应用于解释植物地上-地下关系、种群动态变化、群落构建过程和生物多样性维持等。人工林是森林生态系统的重要组成部分,在木材生产、固碳释氧、水土保持、防风固沙、生物多样性维持等方面发挥重要作用。陇中黄土高原是黄河流域生态保护和高质量发展国家战略实施的关键区,也是典型的半干旱生态脆弱区以及水土流失防治的重点区。自上世纪60年代以来该区进行了大规模人工植树造林特别是水土保持防护林的建设,人工防护林植物-土壤互馈作用研究是评估人工防护林稳定性及其功能质量,预测人工林生态系统演变方向的关键,其对生态脆弱区生态恢复与林业可持续发展具有重要意义。为深入理解陇中黄土高原主要人工防护林植物-土壤互馈作用关系,本研究以柽柳(Tamarix chinensis)、河北杨(Populus hopeiensis)、油松(Pinus tabuliformis)及山杏(Prunus sibirica)4种黄土高原主要人工乔木防护林和不同造林年限(13年、35年、55年)柠条(Caragana korshinskii)灌木防护林为研究对象,通过野外调查采样和室内测试分析,以期明确不同类型人工乔木林及不同林龄柠条灌木林对土壤理化性质和土壤质量的影响,进而揭示土壤属性的改变与人工防护林根和叶功能性状特征的关系,最后根据人工乔木林土壤微生物群落特征变化探讨人工防护林植物-土壤互馈作用机制。主要研究结果如下:

(1)4种人工乔木防护林对土壤质地类型、土壤容重、含水率、pH等土壤物理性质的影响大小依次为河北杨>油松>山杏>柽柳,土壤全碳和有机碳含量也表现为河北杨>油松>山杏>柽柳,而土壤全氮和速效氮含量依次为河北杨>山杏>油松>柽柳,土壤全磷含量则油松>山杏>河北杨>柽柳,土壤速效磷含量依次为油松>柽柳>山杏>河北杨;人工柠条灌木林下土壤随着造林年限增加,土壤中黏粒和粉粒含量均显著增加,而砂粒含量则显著下降,土壤容重和pH逐渐降低,土壤全碳含量、有机碳含量、全氮含量、全磷含量和速效磷含量均随造林年限增加呈递增趋势,而速效氮则呈先减后增趋势。同时,人工乔木防护林土壤质量指数范围为0.56-1.46,且河北杨>油松>山杏>柽柳,而人工灌木柠条土壤质量指数范围为0.60-2.40,且随造林年限增加土壤质量指数显著增加趋势,造林年限越长土壤质量提升愈加明显。

(2)4种人工乔木防护林土壤有机碳含量、全氮含量、全磷含量、总孔隙度与叶片碳含量、干物质量、平均叶面积、细根碳含量以及比根长呈正相关,土壤容重与细根氮含量、细根磷含量和细根干物质量间呈正相关,且土壤总孔隙度与细根碳含量和比根长也呈正相关;人工柠条灌木林土壤养分与叶片磷含量、叶片干物质含量、细根碳含量、细根氮含量以及细根干物质量间呈正相关,土壤容重与叶片氮含量、叶片磷含量、比叶面积、平均叶面积、比根长和细根磷含量也呈正相关,而与细根氮含量、细根碳含量呈负相关。土壤有机碳、土壤氮含量和磷含量是影响柽柳、河北杨、油松和山杏叶片功能性状的主要因素,而柠条叶片功能性状较少受土壤养分含量的影响;细根功能性状主要受土壤容重与土壤孔隙度的影响,但柠条细根功能性状受土壤容重与土壤孔隙度的影响小于人工乔木防护林树种。

(3)4种人工乔木防护林土壤中共检测到33个细菌门,以放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)和芽单胞菌门(Gemmatimonadetes)为优势菌门,其相对丰度占细菌群落的84.31-88.41%。土壤细菌多样性和群落组成在不同树种间存在显著差异,土壤细菌群落主要受到确定性的异质选择作用调控,而土壤酶活性、盐度和有机质含量是影响细菌群落的主要环境因素。共现网络分析发现,4种人工乔木防护林土壤细菌物种间的负相关连接数均高于正相关连接数,表明土壤细菌群落中的物种对不同乔木林土壤的异质性表现出异步的、互补的适应响应。结合共现网络的多个拓扑属性发现,共现网络结构的复杂程度依次为油松>柽柳>河北杨>山杏,表明陇中黄土高原油松人工林土壤细菌群落更加稳定,进而更有利的促进该区域植被-土壤细菌-土壤肥力间的反馈循环。

(4)4种人工乔木防护林土壤中共检测到6个真菌门,以担子菌门(Basidiomycota)、子囊菌门(Ascomycota)和毛霉亚门(Mucoromycotina)为优势类群,其相对丰度占真菌群落的85.56-92.26%。土壤真菌多样性和群落组成在不同人工林树种间同样具有明显差异。不同于细菌群落,随机性过程主要驱动了土壤真菌的群落构建,且确定性过程的作用较弱。共现网络分析发现,4种乔木林土壤真菌物种间的负相关连接数同样均高于正相关。结合网络结构的拓扑特征发现,网络的复杂程度和稳定性依次为柽柳>河北杨>山杏>油松,表明在陇中黄土高原柽柳人工林在稳定土壤真菌群落且增强植被-土壤真菌-土壤肥力间的互馈作用方面优于其他三个树种。

综上所述,不同类型人工乔木防护林土壤肥力存在明显差异,且人工柠条灌木林随造林年限增加,其对土壤质量提升作用愈强,土壤肥力亦可反向影响人工防护林的叶和根功能性状特征,人工防护林土壤理化特征及肥力是影响微生物群落结构的主要因素,油松人工林能形成更为稳定的土壤细菌微生物群落而柽柳人工林则形成更为稳定的土壤真菌群落。以上研究结果不仅加深了黄土高原主要人工防护林植物-土壤互馈作用机制的认识,并可为该区人工防护林建设和管理提供了重要科技支撑。

Other Abstract

Plant-soil interaction mainly refers to the process in which plant growth changes the biological and abiotic properties of the soil in its growth environment, and the changed soil properties then react on plant growth. Its core is to reveal the interaction relationship between plants and soil biological and abiotic environments. Plant-soil interaction is widely used to explain plant aboveground underground relationships, population dynamics, community construction processes, and biodiversity maintenance. Artificial forests are an important component of forest ecosystems, playing an important role in wood production, carbon and oxygen fixation, soil and water conservation, wind and sand prevention, and biodiversity maintenance. The Longzhong Loess Plateau is a key area for the implementation of the national strategy for ecological protection and high-quality development in the Yellow River Basin, as well as a typical semi-arid ecological fragile area and a key area for soil erosion prevention and control. Since the 1960s, the area has undergone large-scale artificial afforestation, especially the construction of soil and water conservation protective forests. The study of plant-soil interaction in artificial protective forests is crucial for evaluating the stability and functional quality of artificial protective forests, predicting the evolution direction of artificial forest ecosystems, and is of great significance for ecological restoration and sustainable development of forestry in ecologically fragile areas. In order to gain a deeper understanding of the plant-soil interaction relationship in the main artificial protective forests on the Longzhong Loess Plateau, this study focuses on four types of main artificial tree protective forests on the Loess Plateau: T. chinensis, P. hopeiensis, P. tabuliformis and P. sibirica, as well as C. korshinskii shrub protective forests with different afforestation years (13, 35, 55 years). Through field investigation, sampling, and indoor testing analysis, the aim is to clarify the effects of different types of artificial tree forests and different ages of caragana shrub forests on soil physicochemical properties and soil quality, and to reveal the relationship between changes in soil properties and the functional characteristics of roots and leaves of artificial protective forests. Finally, based on the changes in soil microbial community characteristics of artificial tree forests, the mechanism of plant soil interaction in artificial protective forests is explored. The main research findings are as follows:

(1)The impacts of four artificial arbor forests types on soil physical properties (soil texture, bulk density, moisture content, pH) were ranked as follows: P. hopeiensis > P. tabuliformis > P. sibirica > T. chinensis. The content of soil total carbon and organic carbon decreased in the following order: P. hopeiensis > P. tabuliformis > P. sibirica > T. chinensis. The content of soil total nitrogen and available nitrogen decreased in the following order: P. hopeiensis > P. sibirica > P. tabuliformis > T. chinensis. The content of soil total phosphorus decreased in the following order: P. tabuliformis > P. sibirica > P. hopeiensis > T. chinensis. The content of soil available phosphorus decreased in the following order: P. tabuliformis > T. chinensis > P. sibirica > P. hopeiensis.With the increase of afforestation years, the content of clay and powder particles in the soil under the artificial C. korshinskii shrub forest significantly increased, while the content of sand particles significantly decreased. The soil bulk density and pH gradually decreased. The total carbon content, organic carbon content, total nitrogen content, total phosphorus content, and available phosphorus content of the soil all showed a decreasing trend with the increase of afforestation years, while the available nitrogen showing a first decreasing and then increasing trend. At the same time, the soil quality index of artificial arbor forest ranged from 0.56 to 1.46, and the soil quality index range of P. hopeiensis > P. tabuliformis > P. sibirica > T. chinensis, while the soil quality index range of artificial shrub C. korshinskii was 0.60-2.40, showing a significant increase with increasing afforestation years. The longer the afforestation years, the more obvious the improvement of soil quality.

(2) There was a positive correlation between soil organic carbon content, total nitrogen content, total phosphorus content, total porosity and leaf carbon content, dry matter quality, average leaf area, fine root carbon content, and specific root length in four types of artificial arbor forests. There was a positive correlation between soil bulk density and fine root nitrogen content, fine root phosphorus content, and fine root dry matter quality. Additionally, there was a positive correlation between soil total porosity and fine root carbon content and specific root length; There was a positive correlation between soil nutrients and leaf phosphorus content, leaf dry matter content, fine root carbon content, fine root nitrogen content, and fine root dry matter quality in artificial C. korshinskii shrub forests. Soil bulk density was also positively correlated with leaf nitrogen content, leaf phosphorus content, specific leaf area, average leaf area, specific root length, and fine root phosphorus content, while it was negatively correlated with fine root nitrogen content and fine root carbon content. Soil organic carbon, soil nitrogen content, and phosphorus content were the main factors affecting the functional traits of T. chinensis, P. hopeiensis, P. tabuliformis and P. sibirica, while C. korshinskii leaves were less affected by soil nutrient content; The fine root functional traits were mainly influenced by soil bulk density and soil porosity, but the influence of soil bulk density and soil porosity on the fine root functional traits of C. korshinskii was smaller than that of artificial tree protection forest species.

(3) A total of 33 bacterial phyla were detected in the soil of four artificial arbor forests, with Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Gemmatimonadetes as the dominant phyla, accounting for 84.31-88.41% of the bacterial community's relative abundance. There were significant differences in soil bacterial diversity and community composition among different tree species. Soil bacterial communities were mainly regulated by deterministic heterogeneous selection, and soil enzyme activity, salinity, and organic matter content are the main environmental factors affecting bacterial communities. The co-occurrence network analysis found that the negative correlation connection number among soil bacterial species in the four artificial tree protection forests was higher than the positive correlation connection number, indicating that the species in the soil bacterial community showed asynchronous and complementary adaptive responses to the heterogeneity of soil in different tree forests. Based on the multiple topological properties of the co-occurrence network, it was found that the complexity of the co-occurrence network structure was in the order of P. tabuliformis > T. chinensis > P. hopeiensis > P. sibirica, indicating that the soil bacterial community of P. tabuliformis artificial forest in the Longzhong Loess Plateau was more stable, which was more conducive to promoting the feedback cycle between vegetation, soil bacteria, and soil fertility in the region.

(4) A total of 6 fungal phyla were detected in the soil of 4 artificial arbor forests, with Basidiomycota, Ascomycota, and Mucor mycotina as the dominant groups, accounting for 85.56-92.26% of the fungal community's relative abundance. The diversity and community composition of soil fungi also showed significant differences among different artificial forest species. Unlike bacterial communities, stochastic processes mainly drive the construction of soil fungal communities, and the role of deterministic processes was relatively weak. The co-occurrence network analysis found that the negative correlation connections between soil fungal species in the four tree forests were also higher than the positive correlation. Based on the topological characteristics of the network structure, it was found that the complexity and stability of the network were in the order of T. chinensis > P. hopeiensis > P. sibirica > P. tabuliformis, indicating that T. chinensis artificial forest in the Longzhong Loess Plateau was superior to the other three tree species in stabilizing soil fungal communities and enhancing the mutual feedback between vegetation, soil fungi, and soil fertility.

In summary, there were significant differences in soil fertility among different types of artificial arbor forests, and as the afforestation years increase, the artificial C. korshinskii shrub forest has a stronger effect on improving soil quality. Soil fertility can also reverse affect the leaf and root functional characteristics of artificial protective forests. The physical and chemical characteristics and fertility of artificial protective forest soil are the main factors affecting the structure of microbial communities, The P. tabuliformis plantation can form a more stable soil bacterial and microbial community, while T. chinensis plantation can form a more stable soil fungal community. The above research results not only deepen the understanding of the plant soil interaction mechanism of the main artificial protective forests in the Loess Plateau, but also provide important technological support for the construction and management of artificial protective forests in the region.

MOST Discipline Catalogue理学 - 生态学
URL查看原文
Language中文
Other Code262010_120190905310
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/539770
Collection生态学院
Affiliation
兰州大学生态学院
Recommended Citation
GB/T 7714
姚文秀. 陇中黄土高原主要人工防护林植物-土壤互馈作用研究[D]. 兰州. 兰州大学,2023.
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