Knowledge Resource Center for Ecological Environment in Arid Area
| 河西走廊荒漠草地碳、氮、磷化学计量特征研究 | |
| 其他题名 | Carbon, nitrogen, and phosphorus stoichiometry characteristics in desert grassland of the Hexi Corridor |
| 张珂 | |
| 出版年 | 2017 |
| 学位类型 | 博士 |
| 导师 | 苏永中 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 荒漠草地面积约占我国北方草地面积的47.4%，其水分、养分循环的稳定维持对我国北方地区的生态安全至关重要。在干旱荒漠生态系统中，植被的生长不仅受有限降水的影响，而且受土壤中氮、磷营养元素的限制。同时，凋落物数量、质量及分解速率等又是影响土壤中养分元素含量及有效性的重要因素。因此，对荒漠草地生态系统中植物、凋落物及土壤养分循环的研究可以深入认识荒漠生态系统中的养分分布特征和调控因素，揭示养分元素之间的相互作用及平衡制约关系，从而为荒漠草地生态系统的植被管理和恢复提供新的思路和理论依据。生态化学计量学是研究区域尺度上碳、氮、磷养分循环及平衡的重要理论工具，近年来得到了广泛的应用。本文以河西走廊荒漠草地为研究对象，调查了荒漠草地物种及土壤颗粒组成，分析了荒漠草地植物、凋落物及土壤中碳、氮、磷化学计量特征及其影响因素，并进一步讨论了荒漠草地植被氮、磷的内稳性特征，主要结果和结论如下：（1）河西走廊荒漠草地主要由67种物种组成，分属20科53属，物种多样性较低且分布不均匀。草地土壤为砂质土壤且有大量的砾石分布。随年均降水量及植被盖度的增加，土壤粉粒、粘粒含量显著增加。（2）荒漠草地土壤有机碳（SOC）、全氮（TN）和全磷（TP）的化学计量特征主要受年均降水量及年均温度的影响。随土壤深度的增加，土壤SOC、TN、TP、C:P和N:P逐渐降低，而C:N的变化幅度较小。0-30 cm土壤中SOC、TN和TP含量分别占0-100 cm 土壤中SOC、TN和TP含量的83.9%、83.4%和81.3%。土壤SOC、C:N及C:P在空间分布上变异较大，且土壤SOC是决定土壤C:N和C:P变异的重要因素。土壤SOC、TN、TP及C:N:P均与盖度、生物量和干旱指数呈显著的正相关，土壤SOC、TN、TP、C:P和N:P与土壤粉粒+粘粒和年均降水量呈显著的正相关，C:N与年均温度呈显著的负相关。（3）荒漠草地植物叶片C、N和P的化学计量特征主要受降水量或土壤水分的影响。叶片C、N和P平均含量分别为369.06 mg g-1、20.80 mg g-1和1.36 mg g-1，变化范围分别为247.77~517.16 mg g-1、4.99 ~49.42 mg g-1和0.59~3.09 mg g-1；C:N、C:P和N:P平均值分别为21.00、294.73和15.59，变化范围分别为8.39~75.50、151.73~697.33和4.20~29.93。在不同器官中，N、P含量在叶片中最高，在根中最低；C含量在根中最高，在叶片中最低。叶片C与N和P呈负相关，但不显著，N和P呈显著的正相关。叶片N与C:N和P与C:P的相关系数较大，N与N:P呈显著的正相关，而P与N:P无显著的相关关系。叶片C含量与SOC、年均降水量、经度、土壤含水量及干旱指数呈显著的正相关，与纬度呈显著的负相关；叶片N含量和N:P与土壤含水量和经度呈显著的负相关；叶片P含量与土壤含水量和经度呈负相关，但不显著。（4）荒漠草地凋落物C、N和P的化学计量特征主要受年均降水量的影响。凋落物C、N和P的平均含量分别为393.16 mg g-1、11.00 mg g-1和0.79 mg g-1，变化范围为134.96~477.35 mg g-1、2.21~36.64 mg g-1和0.17~2.15 mg g-1；C:N、C:P和N:P平均值分别为40.74、578.13和14.99，变化范围分别为9.51~112.96、171.30~2610.32和3.69~43.67。凋落物C含量的变异系数较小。凋落物C与N无显著相关关系，C与P呈显著负相关，N与P呈显著正相关关系。凋落物C与土壤水分、粉粒+粘粒、经度呈显著负相关，与纬度呈显著正相关；N、P含量与植被盖度、土壤养分、粉粒+粘粒、经度、海拔高度、年均降水量呈正相关，与土壤容重及年均温度呈负相关。 （5）荒漠草地地上生物量及养分储量高于地下，且地下生物量和养分储量主要集中在0-30 cm。凋落物生物量和养分储量最低。生物量与C储量的相关系数最大。C、N、P储量在地上、凋落物和地下均呈显著的相关关系。C、P储量在地上、凋落物和地下三者间均呈等速增长；N储量在地上的增长速率小于地下，N储量在地上与凋落物、凋落物与地下均呈等速增长。土壤、地理及气候因子解释了地上、凋落物、地下生物量及养分储量变化的72.3%。 （6）植物地上部分N、P和N:P内稳性指数分别为4.76、4.35和5.88；地下部分N、P和N:P内稳性指数分别为3.85、25.00和2.24。灌木优势样地N和N:P内稳性高于草本样地且草本优势样地地上和地下P不具有内稳性。群落P的内稳性指数与物种丰富度、多样性指数及均与度呈显著的正相关关系，而群落N和N:P的内稳性指数与群落特征无显著关系。 |
| 英文摘要 | Desert grassland accounts for about 47.4% of the north grassland in China. The stability of water and nutrient cycles in desert grassland plays a critical role on the ecological security of the north China. In the arid desert ecosystem, plant growth is not only limited by limited precipitation, also controlled by the limited nutrient, especially for nitrogen and phosphorus in soils. Meanwhile, the quantity, quality, and decomposition rate of litter have great effects on soil nutrient concentration and nutrient availability. Therefore, it will provide a deeper understanding on the distribution of elements and the regulation of related factors in desert grassland ecosystem by studying the element cycles in plant, litter, and soil. Meanwhile, it is helpful to reveal the interaction and the balance mechanism of nutrient in desert grassland ecosystem. As a result, it will provide new perspectives and important theoretical basis for the management and recovery of desert grassland ecosystem. Currently, as an important theoretical instrument to study the cycle of carbon, nitrogen, and phosphorus, ecological stoichiometry was widely applied at regional scale. In present study, we investigated the species and soil particles composition in desert grassland of Hexi Corridor. And then, we analyzed the stoichiometric characteristics of carbon, nitrogen, and phosphorus in plant, litter, and soil in the desert grassland ecosystem of Hexi Corridor. Furthermore, we discussed the homeostasis characteristics of nitrogen and phosphorus. The main results and conclusions are shown below.(1) Desert grassland of Hexi Corridor was composed by 67 species, belonging to 20 families and 53 genera, with lower species diversity and uneven distribution. The soil was mainly sandy soil with large amounts of gravel. With the increase of mean annual precipitation and vegetation coverage, soil silt and clay content increased. (2) The stoichiometric characteristics of soil organic carbon (SOC), total nitrogen (TN) , and total phosphorus (TP) were mainly influenced by mean annual precipitation and temperature. With the increase of soil depth, SOC, TN, TP, C:P, and N:P decreased significantly, however, soil C:N showed a narrow variation. At 0-30 cm, SOC, TN, and TP accounted for 83.9%, 83.4%, and 81.3% of those in 0-100 cm, respectively. SOC, C:N, and C:P displayed widely variation in the regional distribution and SOC played a key role in the variation of C:N and C:P. SOC, TN, TP, and their ratios showed significant positive correlation with coverage, biomass, and the the aridity degree. SOC, TN, TP, C:P, and N:P also showed significant positive correlation with soil silt and clay content, mean annual precipitation. C:N showed significant negative correlation with mean annual temperature. (3) The stoichiometric characteristics of leaf C, N, and P were mainly influenced by mean annual precipitation or soil water content. Leaf C, N, P, C:N, C:P and N:P were 369.06 mg g-1, 20.80 mg g-1, 1.36 mg g-1, 21.00, 294.73 and 15.59, respectively. The variations were 247.77~517.16 mg g-1 for C, 4.99 ~49.42 mg g-1 for N, 0.59~3.09 mg g-1 for P, 8.39~75.50 for C:N, 151.73~697.33 for C:P, and 4.20~29.93 for N:P, respectively. Roots had lowest N and P content and highest C content. Leaf N had significant positive relationship with N:P and leaf P had no significant relationship with N:P. Leaf C showed significant positive correlation relationships with SOC, mean annual precipitation, longitude, soil water content and aridity degree. Leaf C showed significant negative correlation relationship with latitude. Leaf N and N:P showed significant negative correlation relationships with soil water content and longitude. Leaf P showed negative correlation relationships with soil water content and longitude.(4) The stoichiometric characteristics of litter C, N, and P were mainly influenced by mean annual precipitation. Litter C, N, P, C:N, C:P and N:P were 393.16 mg g-1, 11.00 mg g-1, 0.79 mg g-1, 40.74, 578.31 and 14.99, respectively. The variations were 2134.96~477.35 mg g-1 for C, 2.21~36.64 mg g-1 for N, 0.17~2.15 mg g-1 for P, 9.51~112.96 for C:N, 171.30~2610.32 for C:P, and 3.69~43.67 for N:P, respectively Litter C had a narrow variation. Litter C had no significant relationship with litter N, but had significant negative relationship with litter P. Litter N and P showed significant positive relationship. Litter C content showed significant negative relationship with soil water content, silt+clay and longitude. Litter N and P showed significant positive relationship with coverage, soil water content, silt+clay, longitude, altitude, and mean annual precipitation, meanwhile, showed negative correlation with soil bulk density and mean annual temperature. (5) Shoot had higher biomass and nutrient storage than roots and litter. Litter had lowest biomass and nutrient storage. Roots biomass and nutrient storage mainly concentrated on 0-30 cm. C, N, and P storage in shoot, litter, and roots had significant relationships. Scaling relationships of C and P storage in shoot, litter, and root were isometric. N storage in root increased faster than it in shoot. Scaling relationships of N storage in shoot and litter and in litter and root were isometric. Environment factors explained 72.3% variation of biomass and nutrient storage. (6) The homeostasis value of shoot N, P, and N:P were 4.76, 4.35, and 5.88. Homeostasis of root N, P, and N:P were 3.85, 25.00, and 2.24. Shrub had higher homeostasis value of N, P, and N:P than grass. At the community level, the homeostasis value of P showed significant positive correlation with species richness, diversity, and evenness. |
| 中文关键词 | 荒漠草地 ; 物种组成 ; 养分化学计量特征 ; 内稳性 |
| 英文关键词 | desert grassland species composition nutrient stoichiometric characteristics homeostasis |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287939 |
| 推荐引用方式 GB/T 7714 | 张珂. 河西走廊荒漠草地碳、氮、磷化学计量特征研究[D]. 中国科学院大学,2017. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [张珂]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [张珂]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [张珂]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
