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Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (9): 27-37.DOI: 10.11686/cyxb2020347

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Effect of temperature changes on nitrogen mineralization in soils with different degradation gradients in Gahai Wetland

Liang-cui SONG(), Wei-wei MA(), Guang LI, Shuai-nan LIU, Gang LU   

  1. College of Forestry,Gansu Agricultural University,Lanzhou 730070,China
  • Received:2020-07-20 Revised:2020-09-09 Online:2021-08-30 Published:2021-08-30
  • Contact: Wei-wei MA

Abstract:

Nitrogen (N) mineralization is a major component in the process of soil N cycling. To further understand soil N cycling in the context of global warming, it is important to explore the effect of temperature variation on soil net nitrogen mineralization rate in alpine Wetland soils with different degradation status. In this research, Gahai Wetland was selected as a model system for study, and a methodology involving indoor incubation of soil samples for 69 days and periodic rinsing was used to study the soil N mineralization characteristics in three soil layers (0-10 cm, 10-20 cm, 20-40 cm) of a four-step soil degradation gradient (non-degraded, mildly-degraded, moderately-degraded and severely-degraded) under the condition of different temperature cultivation. The results indicate that: 1) For the same degeneration level, with increasing temperature, soil net nitrogen mineralization rate and nitrification rate rose, however, ammoniation rate initially increased and then reduced. By fitting the results with a first-order kinetic equation, we found that the maximum value of soil nitrogen mineralization occurred at a culture temperature of 35 ℃. Under the same temperature level, soil nitrogen mineralization potential (N0) showed significant differences depending on the extent of soil degradation, reflecting the potential for soil nitrogen mineralization. 2) Soil nitrogen mineralization and nitrification rates for a particular temperature, soil degradation status, and soil layer decreased with increasing duration of soil culture. Initially rates were high, and over time they slowed. 3) There was a significant difference in soil nitrogen mineralization along the degradation gradients, we ranked the net nitrogen mineralization over the 69 days of incubation for soils with different degradation status and temperature, results were: mineralization at 15 ℃<25 ℃<35 ℃. Our results indicate that temperature has a substantial influence on the process of soil nitrogen mineralization, and high temperature speeds up the process of soil nitrogen mineralization.

Key words: nitrogen mineralization, global warming, Gahai Wetland