Greater stimulation of greenhouse gas emissions by stored yak urine than urea in an alpine steppe soil from the Qinghai-Tibetan Plateau: A laboratory study
Greater stimulation of greenhouse gas emissions by stored yak urine than urea in an alpine steppe soil from the Qinghai-Tibetan Plateau: A laboratory study
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青藏高原高寒草原土壤中储存的牦牛尿比尿素对温室气体排放的刺激更大：一项实验室研究
DOI：
10.1111/grs.12164
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发表时间：
2017
影响因子：
1.3
通讯作者：
Liu Xiuping
中科院分区：
文献类型：
--
作者：
Cai Yanjiang;Du Ziyin;Yan Yan;Wang Xiaodan;Liu Xiuping
放牧动物尿液沉积以尿素为主要成分，是草地生态系统中重要的氮(N)源，并可能影响三种强效温室气体（ghg）的产生：一氧化二氮（N2O）、甲烷（CH4）和二氧化碳（CO2）。然而，由于尿液具有更大的化学复杂性，尿液对温室气体排放的影响可能与尿素不同，这种差异尚未得到很好的报道。与不施氮相比，尿素对土壤铵态氮（NH4+ -N）浓度的增加幅度更大，而牦牛尿对土壤溶解有机碳浓度的增加幅度更大。60% WHC条件下累积N2O和ch4排放量大于20% WHC条件下（P<0.05），但土壤含水量对co2排放没有影响（P<0.05）。两种N添加速率之间N2O或ch4的排放差异无统计学意义（P>0.05），无论N类型如何。添加氮后，尿液中N2O和ch4排放量的增加大于尿素处理，特别是在60% WHC下。两种土壤含水量处理的平均co2排放量随氮添加量的增加而增加，但两种尿素处理的平均值与对照相似。储存牦牛尿液处理中较大的温室气体排放可能是由于固有有机碳的存在。
Urine deposition by grazing animals, with urea as the major constituent, is an important nitrogen (N) source in grassland ecosystems and may affect the production of three potent greenhouse gases (GHGs): nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). However, owing to the greater chemical complexity of urine, the effect of urine on GHG emissions may differ from that of urea, and this difference has not been well reported. A short‐term laboratory study was conducted to examine the influence of stored yak urine and urea at addition rates of 350 and 700 mg N m−1soil on GHG emissions at 20 and 60% water holding capacity (WHC) in an alpine steppe soil from the Qinghai‐Tibetan Plateau. Compared with no N addition, urea led to greater increases in soil ammonium N (NH4+–N) concentrations, while yak urine resulted in a greater increase in soil dissolved organic carbon concentrations. Greater (P<0.05) cumulative N2O and CH4emissions occurred under 60% than 20% WHC, but soil moisture content did not affect CO2emissions (P>0.05). There were no statistically significant (P>0.05) differences in N2O or CH4emissions between the two N‐addition rates, regardless of N type. The increases in N2O and CH4emissions after N addition were greater in the urine than in the urea treatments, particularly under 60% WHC. The average CO2emissions for the two soil moisture contents in the urine treatments increased with increasing N‐addition rate, but the two urea treatments showed similar values to the control. The greater GHG emissions in the stored yak urine treatments were probably due to the existence of intrinsic organic carbon. Our results suggest that fresh yak urine may also possibly cause more GHG losses than urea under equivalent N application rates in alpine steppe soil on the Qinghai‐Tibetan Plateau.