摘要
选取内蒙古锡林郭勒典型草原区两种不同退化程度草原群落（轻度和重度退化草原群落）,设置氮素添加梯度实验（分别添加NH4NO30,30,50,80 g·m-2）,分析退化草原土壤有机质含量对氮素添加的响应,意图找出氮肥作用于不同退化程度草原时的最适值。结果表明,不同退化程度的草原对于氮素添加的响应不同：对于轻度退化草原,氮素添加对土壤有机质的影响主要集中在0～20 cm土层,30 g· m-2处理时土壤有机质显著高于其他3个氮素水平,氮素的添加显著提高土壤有机质含量,说明氮素是轻度退化草原主要的限制因子；对于重度退化草原,当施氮量为30 g·m-2时,0～10 cm层土壤有机质含量相对较高,但没有达到统计学上的显著差异。土壤有机质在氮素添加梯度下各层变化不显著,说明氮素不是重度退化草原的主要限制因子。
In this study we selected two communities in different degree of degraded grasslands （ lightly degraded grassland and heavily degraded grassland ） in Xilin Gol, Inner Mongolia. Then we set up nitrogen addition rate test （respectively adding NH4NO3 0g/m2, 30g/m2, 50g/m2 , 80g/m2 ） to analyze the response of the soil organic matter content on the nitrogen adding gradient,and find the optimal values of nitrogen fertilizer applied at different degree of degraded grassland. The results showed that the response of the different degree of degraded grassland to nitrogen addition is different. For lightly degraded grassland, the response of nitrogen addition on soil organic matter is mainly concentrated in the 0-20cm layer, and nitrogen addition at a rate of 30g/m2 , soil organic matter was significantly higher than the other three nitrogen levels, nitrogen addition significantly increased soil organic matter content, which meant that nitrogen is the major limiting factor in lightly degraded grassland. For heavily degraded grassland, when ni-trogen rate was 30g/m2 , 0-10cm layer of soil organic matter content is relatively high, but did not reach a statistically significant difference. Adding nitrogen gradient did not change soil or-ganic matter content significantly, which meant that nitrogen is not the main limiting factor in heavily degraded grassland.
出处
《大连民族学院学报》
CAS
2015年第3期202-206,共5页
Journal of Dalian Nationalities University
基金
国家自然科学基金项目(30771528)
国家环保公益性行业科研专项(201109025-03B)
国家火炬计划项目(2012GH531899)
辽宁省教育厅科研项目(L2012474)
中央高校基本科研业务费专项资金资助项目(DC201502070303)
关键词
退化草原
土壤有机质
氮素添加梯度
响应
degraded grassland
soil organic matter
nitrogen addition rate
response
