Effects of warming and nitrogen deposition on the coupling mechanism between soil nitrogen and phosphorus in Songnen Meadow Steppe, northeastern China

• Published in: Soil biology & biochemistry Vol. 65; pp. 96 - 104
• Main Authors: Zhang, Nanyi, Guo, Rui, Song, Piao, Guo, Jixun, Gao, Yingzhi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.10.2013; Elsevier
• Subjects: Agronomy. Soil science and plant productions; ammonium nitrate; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; China; Coupling mechanism; ecosystems; Fundamental and applied biological sciences. Psychology; Global change; global warming; industrialization; infrared heaters; meadows; mineralization; N addition; nitrogen; nitrogen content; phosphorus; Physics, chemistry, biochemistry and biology of agricultural and forest soils; soil heating; Soil nitrogen; soil nutrients; Soil phosphorus; soil productivity; Soil science; soil temperature; steppe soils; steppes; Warming; Asia; China; China, People's Rep; Warming; Soil phosphorus; N addition; Global change; Soil nitrogen; Coupling mechanism; Grassland; Phosphorus; Nitrogen; Soils; Steppe; Soil science; Deposition
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2013.05.015

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−2 a−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.