Effects of warming and nitrogen deposition on the coupling mechanism between soil nitrogen and phosphorus in Songnen Meadow Steppe, northeastern China
Effects of warming and nitrogen deposition on the coupling mechanism between soil nitrogen and phosphorus in Songnen Meadow Steppe, northeastern China
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DOI：
10.1016/j.soilbio.2013.05.015
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发表时间：
2013-10
影响因子：
9.7
通讯作者：
N. Zhang;R. Guo;Piao Song;Jixun Guo;Yingzhi Gao
中科院分区：
文献类型：
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作者：
N. Zhang;R. Guo;Piao Song;Jixun Guo;Yingzhi Gao
松嫩草甸草原是我国东北地区的典型草原类型，受全球气候变暖和大气氮沉降增加的影响日益严重。然而，草原土壤中氮、磷对全球变暖和氮沉降双重效应的响应及其耦合机制尚不清楚。在原位条件下，研究了模拟大气变暖和氮沉降对松嫩草原土壤氮、磷的影响以及氮、磷耦合作用。自2006年以来，使用红外加热器将土壤温度提高了约1.7 °C。每年用硝酸铵水溶液以10 g m−2a−1的速率处理一次氮添加物。在为期四年的研究中，增加氮的数量增加全氮，有效氮，以及氮矿化率在土壤中。土壤全磷和速效磷含量明显降低。因此，N：P比增加，N和P之间的耦合降低。单独施氮和增温与施氮相结合的土壤N：P值相近，表明松嫩草甸草原土壤增温对土壤N：P值影响不大。随着我国工业化进程的加快，氮沉降量不断增加。松嫩草甸草原是我国东北地区的典型盐碱土分布区。因此，松嫩草甸草原土壤磷限制增加的发现对中国东北地区的生态系统具有重要意义。草地土壤养分的合理调控与管理对提高土壤生产力、促进草地生态系统的可持续利用具有重要意义。
Songnen Meadow Steppe, which is in northeast China, is increasingly affected by global warming and incremental increases in atmospheric nitrogen deposition. However, the responses of nitrogen (N) and phosphorus (P) in steppe soil, and of the coupling mechanism between them, to the dual effects of global warming and N deposition are still unknown. In this study, the effects of simulated atmospheric warming and N deposition on N and P in Songnen steppe soil, as well as on the coupling between N and P, were examined under in situ conditions. Infrared heaters were used to elevate soil temperature by approximately 1.7 °C since 2006. N additions were treated once a year with aqueous ammonium nitrate at a rate of 10 g m−2a−1. During the four-year study, addition of N increased the amount of total N, and available N, as well as the rate of N mineralization in the soil. Moreover, the amounts of total P and available P in the soil were considerably reduced. Thus, the N:P ratio increased, and the coupling between N and P decreased. Similar values for the N:P ratio were obtained for the addition of N by itself and for the combination of warming and addition of N, which indicates that a small amount of soil warming in Songnen Meadow Steppe would not have a substantial effect on the ratio. With the growth of China's industrialization, N deposition continues to increase. The study area of Songnen Meadow Steppe, and northeast China in general, are characterized by widespread distribution of saline alkali soil. Therefore, the finding of increased P limitation in the soil of Songnen Meadow Steppe has major implications for ecosystems in northeast China. Reasonable regulation and management of meadow soil nutrients will be of great importance in increasing soil productivity and promoting sustainable use of grassland ecosystems.