氮磷添加对北方草原生态系统群落和碳氮磷化学计量特征的影响
李冬冬
Subtype硕士
Thesis Advisor焦峰
2020-05-25
Degree Grantor中国科学院大学(中国科学院教育部水土保持与生态环境研究中心)
Place of Conferral北京
Degree Name农学硕士
Degree Discipline水土保持与荒漠化防治
Keyword氮磷添加 物种多样性 生物量 根冠比 生态化学计量特征
Abstract

    由于人们在工业生产和农业种植过程中过渡的依赖化石燃料和化肥,导致全球范围内大气氮沉降的含量连年上升,草地生态系统可能由氮限制慢慢转化为受其他营养元素限制。氮磷在植物代谢中存在协同作用,磷对植物营养浓度的影响与氮添加相关。本研究以内蒙古自治区3种草原类型区(草甸草原、典型草原、荒漠草原)为研究对象,研究氮磷添加对不同草原类型区草原生物量及根冠比,物种多样性和生产力,土壤、叶片和根系CNP及化学计量比的影响,主要结论如下:

1通过对3种草原类型区站点草地群落科的种数分布组成分析,均以禾本科、菊科和豆科三大科为主;而且物种丰富度指数随着氮素或磷素添加浓度呈现降低的趋势,依次为荒漠草原>草甸草原>典型草原。对于物种多样性指数而言,无论氮素或磷素添加对3种草原类型区的Shannon-Wiener指数远远大于Simpson指数和Pielou指数,而且Simpson指数和Pielou指数的大小基本接近,且呈现出相似的变化趋势。物种丰富度指数与年均温和生长季月均温均呈显著负相关(P < 0.05),与年降水量(P < 0.05)和生长季月降水量(P < 0.01)呈显著或极显著的正相关关系。

2氮磷添加试验显著提高了草甸草原和荒漠草原草地群落地上生物量,并且随着施氮浓度越高,地上生物量呈现上升变化趋势,而对典型草原草地群落地上生物量影响不显著(P > 0.05);NP添加显著提高了典型草原和荒漠草原草地群落地下生物量,而对草甸草原草地群落地下生物量略微下降趋势(P > 0.05)。

3)不同N添加水平对三种不同草原类型区草地群落生物量存在正相关关系,同时植物生物量还明显受到年降雨量和干旱指数的影响。不同P添加水平对三种不同草原类型区草地群落地上生物量、地下生物量和总生物量均没有明显的相关关系。NP添加对草原类型区各个生物量也存在一定的差异性(P < 0.05),地下、地下/地上和总生物量的空间分布存差异性最显著。

4)氮添加处理下,对3种不同草原类型区0-10 cm10-30 cm的土壤有机碳和全氮没有显著影响。典型草原类型区0-10 cm10-30 cm土壤C:N均表现为先上升后下降的趋势,其他类型不同土层土壤C:N的基本不变,总体上对土壤C:N影响不显著;草甸草原类型区0-10 cm土壤C:PN:P均下降的趋势,而其它类型区的0-10 cm10-30 cm土壤C:PN:P呈现上升趋势。

5)在氮添加条件下,叶片、根系的CNP各元素之间的相关性相对较弱,相比而言叶片与根系之间的相关性较显著。在氮添加处理下,3种草原类型区叶片-根系的CN之间的相关性比较强,各元素化学计量比相关性相对较弱。在磷添加处理下,典型草原整体相关性比较弱,而草甸草原和荒漠草原相关性比较显著。

由于人们在工业生产和农业种植过程中过渡的依赖化石燃料和化肥,导致全球范围内大气氮沉降的含量连年上升,草地生态系统可能由氮限制慢慢转化为受其他营养元素限制。氮磷在植物代谢中存在协同作用,磷对植物营养浓度的影响与氮添加相关。本研究以内蒙古自治区3种草原类型区(草甸草原、典型草原、荒漠草原)为研究对象,研究氮磷添加对不同草原类型区草原生物量及根冠比,物种多样性和生产力,土壤、叶片和根系CNP及化学计量比的影响,主要结论如下:

1通过对3种草原类型区站点草地群落科的种数分布组成分析,均以禾本科、菊科和豆科三大科为主;而且物种丰富度指数随着氮素或磷素添加浓度呈现降低的趋势,依次为荒漠草原>草甸草原>典型草原。对于物种多样性指数而言,无论氮素或磷素添加对3种草原类型区的Shannon-Wiener指数远远大于Simpson指数和Pielou指数,而且Simpson指数和Pielou指数的大小基本接近,且呈现出相似的变化趋势。物种丰富度指数与年均温和生长季月均温均呈显著负相关(P < 0.05),与年降水量(P < 0.05)和生长季月降水量(P < 0.01)呈显著或极显著的正相关关系。

2氮磷添加试验显著提高了草甸草原和荒漠草原草地群落地上生物量,并且随着施氮浓度越高,地上生物量呈现上升变化趋势,而对典型草原草地群落地上生物量影响不显著(P > 0.05);NP添加显著提高了典型草原和荒漠草原草地群落地下生物量,而对草甸草原草地群落地下生物量略微下降趋势(P > 0.05)。

3)不同N添加水平对三种不同草原类型区草地群落生物量存在正相关关系,同时植物生物量还明显受到年降雨量和干旱指数的影响。不同P添加水平对三种不同草原类型区草地群落地上生物量、地下生物量和总生物量均没有明显的相关关系。NP添加对草原类型区各个生物量也存在一定的差异性(P < 0.05),地下、地下/地上和总生物量的空间分布存差异性最显著。

4)氮添加处理下,对3种不同草原类型区0-10 cm10-30 cm的土壤有机碳和全氮没有显著影响。典型草原类型区0-10 cm10-30 cm土壤C:N均表现为先上升后下降的趋势,其他类型不同土层土壤C:N的基本不变,总体上对土壤C:N影响不显著;草甸草原类型区0-10 cm土壤C:PN:P均下降的趋势,而其它类型区的0-10 cm10-30 cm土壤C:PN:P呈现上升趋势。

5)在氮添加条件下,叶片、根系的CNP各元素之间的相关性相对较弱,相比而言叶片与根系之间的相关性较显著。在氮添加处理下,3种草原类型区叶片-根系的CN之间的相关性比较强,各元素化学计量比相关性相对较弱。在磷添加处理下,典型草原整体相关性比较弱,而草甸草原和荒漠草原相关性比较显著。

由于人们在工业生产和农业种植过程中过渡的依赖化石燃料和化肥,导致全球范围内大气氮沉降的含量连年上升,草地生态系统可能由氮限制慢慢转化为受其他营养元素限制。氮磷在植物代谢中存在协同作用,磷对植物营养浓度的影响与氮添加相关。本研究以内蒙古自治区3种草原类型区(草甸草原、典型草原、荒漠草原)为研究对象,研究氮磷添加对不同草原类型区草原生物量及根冠比,物种多样性和生产力,土壤、叶片和根系CNP及化学计量比的影响,主要结论如下:

1通过对3种草原类型区站点草地群落科的种数分布组成分析,均以禾本科、菊科和豆科三大科为主;而且物种丰富度指数随着氮素或磷素添加浓度呈现降低的趋势,依次为荒漠草原>草甸草原>典型草原。对于物种多样性指数而言,无论氮素或磷素添加对3种草原类型区的Shannon-Wiener指数远远大于Simpson指数和Pielou指数,而且Simpson指数和Pielou指数的大小基本接近,且呈现出相似的变化趋势。物种丰富度指数与年均温和生长季月均温均呈显著负相关(P < 0.05),与年降水量(P < 0.05)和生长季月降水量(P < 0.01)呈显著或极显著的正相关关系。

2氮磷添加试验显著提高了草甸草原和荒漠草原草地群落地上生物量,并且随着施氮浓度越高,地上生物量呈现上升变化趋势,而对典型草原草地群落地上生物量影响不显著(P > 0.05);NP添加显著提高了典型草原和荒漠草原草地群落地下生物量,而对草甸草原草地群落地下生物量略微下降趋势(P > 0.05)。

3)不同N添加水平对三种不同草原类型区草地群落生物量存在正相关关系,同时植物生物量还明显受到年降雨量和干旱指数的影响。不同P添加水平对三种不同草原类型区草地群落地上生物量、地下生物量和总生物量均没有明显的相关关系。NP添加对草原类型区各个生物量也存在一定的差异性(P < 0.05),地下、地下/地上和总生物量的空间分布存差异性最显著。

4)氮添加处理下,对3种不同草原类型区0-10 cm10-30 cm的土壤有机碳和全氮没有显著影响。典型草原类型区0-10 cm10-30 cm土壤C:N均表现为先上升后下降的趋势,其他类型不同土层土壤C:N的基本不变,总体上对土壤C:N影响不显著;草甸草原类型区0-10 cm土壤C:PN:P均下降的趋势,而其它类型区的0-10 cm10-30 cm土壤C:PN:P呈现上升趋势。

5)在氮添加条件下,叶片、根系的CNP各元素之间的相关性相对较弱,相比而言叶片与根系之间的相关性较显著。在氮添加处理下,3种草原类型区叶片-根系的CN之间的相关性比较强,各元素化学计量比相关性相对较弱。在磷添加处理下,典型草原整体相关性比较弱,而草甸草原和荒漠草原相关性比较显著。

Other Abstract

    Due to the large use of chemical fertilizer and fossil fuel combustion, the global atmospheric nitrogen deposition increases year by year, and the grassland ecosystem may be slowly transformed from nitrogen limitation to other nutrients limitation. There is synergism between nitrogen and phosphorus in plant metabolism. The effect of phosphorus on plant nutrient concentration is related to N addition. In this study, three steppe types (meadow grassland, typical grassland, desert grassland) in Inner Mongolia were selected as the research objects to study the effects of nitrogen and phosphorus addition on grassland biomass, root-shoot ratio, species diversity and productivity, soil, leaf and root C, N, P and stoichiometric ratio in different Steppe types. The main conclusions are as follows:

1Based on the analysis of the species distribution and composition of the grassland community families in the three grassland types, Gramineae, Compositae and Leguminosae were the main families, and the species richness index decreased with the concentration of nitrogen or phosphorus, which was followed by desert grassland > meadow grassland > typical grassland. For species diversity index, the Shannon Wiener index of three grassland types was much higher than Simpson index and Pielou index, and the size of Simpson index and Pielou index was similar, and showed similar trend. The species richness index showed a significant negative correlation (P < 0.05) with the annual average temperature and the monthly average temperature in the growth season, and a significant or extremely significant positive correlation with the annual precipitation (P < 0.05) and the monthly precipitation in the growth season (P < 0.01).

2The above ground biomass of meadow steppe and desert steppe community was significantly increased by the experiment of nitrogen and phosphorus addition, and the above ground biomass increased with the higher nitrogen application concentration, but the above ground biomass of typical steppe community was not significantly affected (P > 0.05) N and P increased the underground biomass of typical grassland and desert grassland, but decreased slightly (P > 0.05).

3There was a positive correlation between N addition level and biomass of grassland community in three different grassland types, and plant biomass was also significantly affected by annual rainfall and drought index. There was no significant correlation between the aboveground biomass, the underground biomass and the total biomass of grassland communities in three different grassland types. N and P addition also had a certain difference (P < 0.05) in each biomass of grassland type area, and the spatial distribution of underground, underground/above ground and total biomass had the most significant difference.

4The soil organic carbon and total nitrogen of 0-10 cm and 10-30 cm were not significantly affected by nitrogen addition. The C:N of 0-10 cm and 10-30 cm soils in typical steppe type areas showed a trend of rising first and then declining, while the C:N of other types of soils remained basically unchanged, which had no significant effect on the C:N of soils in general; the C:P and N:P of 0-10 cm soils in meadow steppe type areas decreased, while the C:P and N:P of 0-10 cm and 10-30 cm soils in other types areas showed an upward trend.

5Under the condition of nitrogen addition, the correlation between the elements of C, N and P in leaves and roots is relatively weak, and the correlation between leaves and roots is relatively significant. Under the treatment of nitrogen addition, the correlation between C and N of leaves and roots in three grassland types was strong, and the correlation between the stoichiometric ratio of each element was relatively weak. Under the treatment of phosphorus addition, the overall correlation of typical grassland was weak, while the correlation between meadow grassland and desert grassland was significant.

MOST Discipline Catalogue农学 ; 农学::林学
Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/9198
Collection水保所2018--2020届毕业生论文(学位论文、期刊论文)
Recommended Citation
GB/T 7714
李冬冬. 氮磷添加对北方草原生态系统群落和碳氮磷化学计量特征的影响[D]. 北京. 中国科学院大学(中国科学院教育部水土保持与生态环境研究中心),2020.
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