氮素添加对内蒙古退化草原生产力的短期影响

发布时间：2018-03-25 06:48

本文选题：退化草原　切入点：氮添加　出处：《植物生态学报》2016年10期

【摘要】：不合理的土地利用方式以及气候变化导致我国草原生态系统普遍退化,主要表现在土壤养分降低、植被覆盖度减少、生产力下降。外源氮素添加是促进退化草原尽快恢复的一项重要措施,尤其是对那些退化较为严重的草原。该研究选取内蒙古东乌珠穆沁旗不同退化程度(轻度、中度和重度)的草原群落,于2014 2015年开展连续两年的氮素添加实验,设置对照(不添加)、低水平(5.0 g N·m~( 2)·a~( 1))、中水平(10.0 g N·m~( 2)·a~( 1))和高水平(20.0 g N·m~( 2)·a~( 1))4种氮素添加处理,探讨退化草原群落生产力在恢复过程中对不同水平氮素添加的响应。结果显示:(1)高、中水平氮素添加显著提高了轻度退化群落的地上生物量,分别比对照增加了53.1%、51.6%,氮素各水平添加对中度、重度群落地上生物量无显著影响;(2)高、中水平氮素添加显著提高了轻度退化群落中多年生根茎型禾草地上生物量,分别比对照增加了45.1%、47.7%,而多年生杂类草地上生物量分别比对照减少了37.4%、42.1%,但中度和重度退化群落各功能群生物量的响应不显著;(3)三种水平氮素添加对轻、中、重度退化群落物种丰富度在试验期间均没有显著影响。研究结果表明氮素添加有助于提高轻度退化草原中多年生根茎型禾草的生物量,进而提高群落的生物量,但多年生杂类草会被逐渐替代,导致生物量降低,可见施氮对草原恢复的影响取决于草原退化程度。
[Abstract]:Unreasonable land use patterns and climate change lead to the general degradation of grassland ecosystem in China, which is mainly reflected in the decrease of soil nutrients and vegetation coverage. Exogenous nitrogen supplementation is an important measure to promote the restoration of degraded grasslands, especially for the degraded steppes. The study selected different degrees of degradation (mild, mild) in East Wuzhumqin Banner, Inner Mongolia. Two consecutive years of nitrogen supplementation experiments were conducted in moderate and severe grassland communities in 2014 to 2015. Four nitrogen supplementation treatments were set up under the control (no addition, low level of 5. 0 g Nm ~ (2)) ~ (1) N ~ (2), medium and high levels of 10. 0 g N ~ (2) N ~ (2) A ~ (1) a ~ (1), and 20. 0 g N ~ m (2 ~ 2) a ~ (1) a ~ (1) N ~ (1), respectively. The response of productivity of degraded grassland community to nitrogen supplementation at different levels during restoration was studied. The results showed that the addition of middle level nitrogen significantly increased the aboveground biomass of the degraded community. Compared with the control, the addition of nitrogen increased 53.1% and 51.6, respectively. The addition of nitrogen levels had no significant effect on the aboveground biomass of moderate and severe communities. The addition of medium level nitrogen significantly increased the biomass of perennial rhizomatous grass grassland in mildly degraded communities. Compared with the control, the biomass increased by 45.1 and 47.7, respectively, and the biomass on the perennial hybrid grassland was decreased by 37.4% and 42.1%, respectively, but the response of the biomass of the functional groups of the moderately degraded communities to the biomass of the functional groups in the moderately degraded communities was not significantly different from that of the control, and the response of the three levels of nitrogen supplementation to the biomass of the functional groups in the degraded communities was not significant. The results showed that nitrogen supplementation could increase the biomass of perennial rhizomatous grasses in mildly degraded steppe, and then increase the biomass of the community. But the perennial grasses will be gradually replaced, resulting in a decrease in biomass. It is clear that the effect of nitrogen application on grassland restoration depends on the degree of grassland degradation.
【作者单位】：中国科学院植物研究所植被与环境变化国家重点实验室;中国科学院大学生命科学学院;
【基金】：国家自然科学基金(31670483和31430016) 中国科学院战略性先导科技专项(XDB15010401)
【分类号】：S812

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