Differential responses of short-term soil respiration dynamics to the experimental addition of nitrogen and water in the temperate semi-arid steppe of Inner Mongolia, China

详细信息    查看全文

• 作者：Yuchun Qi^a ; ^{qiyc@igsnrr.ac.cn" class="auth_mail} ; Xinchao Liu^a ; ^b ; Yunshe Dong^a ; ^{dongys@igsnrr.ac.cn" class="auth_mail} ; Qin Peng^a ; Yating He^c ; Liangjie Sun^a ; ^b ; Junqiang Jia^a ; ^b ; Congcong Cao^a ; ^b
• 关键词：soil respiration ; short-term response ; N addition ; simulated rainfall ; temperate steppe
• 刊名：Journal of Environmental Sciences
• 出版年：1 April, 2014
• 年：2014
• 卷：26
• 期：4
• 页码：834-845
• 全文大小：621 K

文摘

We examined the effects of simulated rainfall and increasing N supply of different levels on CO₂ pulse emission from typical Inner Mongolian steppe soil using the static opaque chamber technique, respectively in a dry June and a rainy August. The treatments included NH₄NO₃ additions at rates of 0, 5, 10, and 20 g N/(m²路year) with or without water. Immediately after the experimental simulated rainfall events, the CO₂ effluxes in the watering plots without N addition (WCK) increased greatly and reached the maximum value at 2 hr. However, the efflux level reverted to the background level within 48 hr. The cumulative CO₂ effluxes in the soil rang ed from 5.60 to 6.49 g C/m² over 48 hr after a single water application, thus showing an increase of approximately 148.64% and 48.36% in the effluxes during both observation periods. By contrast, the addition of different N levels without water addition did not result in a significant change in soil respiration in the short term. Two-way ANOVA showed that the effects of the interaction between water and N addition were insignificant in short-term soil CO₂ effluxes in the soil. The cumulative soil CO₂ fluxes of different treatments over 48 hr accounted for approximately 5.34% to 6.91% and 2.36% to 2.93% of annual C emission in both experimental periods. These results stress the need for improving the sampling frequency after rainfall in future studies to ensure more accurate evaluation of the grassland C emission contribution.