1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China;
2 Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China;
3 College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China
Interactive effects of soil temperature and moisture on soil N mineralization in the Stipa krylovii grassland in Inner Mongolia, China
1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China;
2 Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China;
3 College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China
摘要 Determining soil N mineralization response to soil temperature and moisture changes is challenging in the field due to complicated effects from other factors. In the laboratory, N mineralization is highly dependent on temperature, moisture and sample size. In this study, a laboratory incubation experiment was carefully designed and conducted under controlled conditions to examine the effects of soil temperature and moisture on soil N mineralization using soil samples obtained from the Stipa krylovii grassland in Inner Mongolia, China. Five temperature (i.e. 9°C, 14°C, 22°C, 30°C and 40°C) and five moisture levels (i.e. 20%, 40%, 60%, 80% and 100% WHC, where WHC is the soil water holding capacity) were included in a full-factorial design. During the 71-day incubation period, microbial biomass carbon (MBC), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) were measured approximately every 18 days; soil basal respiration for qCO2 index was measured once every 2 days (once a week near the end of the incubation period). The results showed that the mineral N production and net N mineralization rates were positively correlated with temperature; the strongest correlation was observed for temperatures between 30°C and 40°C. The relationships between moisture levels and both the mineral N production and net N mineralization rates were quadratic. The interaction between soil temperature and moisture was significant on N mineralization, i.e. increasing temperatures (moisture) enhanced the sensitivity of N mineralization to moisture (temperature). Our results also showed a positive correlation between the net nitrification rate and temperature, while the correlation between the NH4+-N content and temperature was insignificant. The net nitrification rate was negatively correlated with high NH4+-N contents at 80%–100% WHC, suggesting an active denitrification in moist conditions. Moreover, qCO2 index was positively correlated with temperature, especially at 80% WHC. With a low net nitrification rate and high soil basal respiration rate, it was likely that the denitrification concealed the microbial gross min-eralization activity; therefore, active soil N mineralization occurred in 60%–80% WHC conditions.
Abstract: Determining soil N mineralization response to soil temperature and moisture changes is challenging in the field due to complicated effects from other factors. In the laboratory, N mineralization is highly dependent on temperature, moisture and sample size. In this study, a laboratory incubation experiment was carefully designed and conducted under controlled conditions to examine the effects of soil temperature and moisture on soil N mineralization using soil samples obtained from the Stipa krylovii grassland in Inner Mongolia, China. Five temperature (i.e. 9°C, 14°C, 22°C, 30°C and 40°C) and five moisture levels (i.e. 20%, 40%, 60%, 80% and 100% WHC, where WHC is the soil water holding capacity) were included in a full-factorial design. During the 71-day incubation period, microbial biomass carbon (MBC), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) were measured approximately every 18 days; soil basal respiration for qCO2 index was measured once every 2 days (once a week near the end of the incubation period). The results showed that the mineral N production and net N mineralization rates were positively correlated with temperature; the strongest correlation was observed for temperatures between 30°C and 40°C. The relationships between moisture levels and both the mineral N production and net N mineralization rates were quadratic. The interaction between soil temperature and moisture was significant on N mineralization, i.e. increasing temperatures (moisture) enhanced the sensitivity of N mineralization to moisture (temperature). Our results also showed a positive correlation between the net nitrification rate and temperature, while the correlation between the NH4+-N content and temperature was insignificant. The net nitrification rate was negatively correlated with high NH4+-N contents at 80%–100% WHC, suggesting an active denitrification in moist conditions. Moreover, qCO2 index was positively correlated with temperature, especially at 80% WHC. With a low net nitrification rate and high soil basal respiration rate, it was likely that the denitrification concealed the microbial gross min-eralization activity; therefore, active soil N mineralization occurred in 60%–80% WHC conditions.
This work was funded by the National Natural Science Foun-dation of China (31270500, 31240002), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA05050602), and the Open Research Fund of the Key Laboratory of Vegetation Restoration and Management of De-graded Ecosystems, Chinese Academy of Sciences.
通讯作者:
YingHui LIU
E-mail: lyh@bnu.edu.cn
引用本文:
Yue LI, YingHui LIU, YaLin WANG, Lei NIU, Xia XU, YuQiang TIAN. Interactive effects of soil temperature and moisture on soil N mineralization in the Stipa krylovii grassland in Inner Mongolia, China[J]. 干旱区科学, 2014, 6(5): 571-580.
Yue LI, YingHui LIU, YaLin WANG, Lei NIU, Xia XU, YuQiang TIAN. Interactive effects of soil temperature and moisture on soil N mineralization in the Stipa krylovii grassland in Inner Mongolia, China. Journal of Arid Land, 2014, 6(5): 571-580.
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2014, Vol. 6 
