模拟增温对土壤电导率的影响

Effect of simulated warming on soil conductivity

为研究模拟增温对土壤电导率的影响,为气候变化背景下高寒草地土壤盐渍化趋势动态研究提供理论基础。本研究选择位于青藏高原腹地的三江源草地生态系统监测定位站开展试验,自2015年9月至2017年9月对OTC增温室内外0~15 cm和15~30 cm土壤温度、含水量以及电导率进行同步测定并分析其变化特征。结果表明:①OTC的模拟增温效果明显,与未采用OTC的对照相比,0~15 cm和15~30 cm土壤温度分别增加2. 41℃和1. 27℃;增温导致0~15 cm和15~30 cm的土壤含水量分别增加27. 65%和32. 17%;0~15 cm土壤电导率,增温处理和对照的观测值分别为45. 67μS·m^-1和45. 75μS·m^-1,而15~30 cm土壤电导率增温比对照高158. 09%。②相关性分析表明,在土壤冻结期,土壤温度对土壤电导率的贡献大于土壤湿度,与对照相比,模拟增温条件下土壤含水量与电导率的相关性增加;在土壤消融期,与对照相比,模拟增温条件下0~15 cm和15~30 cm土层土壤温度与电导率的相关性增加,土壤含水量与电导率的相关性随土层深度而不同,0~15 cm土层土壤含水量与电导率的相关性增加,15~30 cm土层土壤含水量与电导率的相关性变化不大。土壤温度对土壤电导率的贡献率高于土壤含水量。

In order to study the effect of simulated warming on soil conductivity,we developed a theoretical basis for the dynamic study of soil salinization trends in alpine grassland affected by climate change. We used the Sanjiangyuan grassland ecosystem monitoring and locating station located in the hinterland of the Qinghai-Tibet Plateau as a focus for our analyses. From September 2015 to September 2017,OTC warming for small indoor and outdoor 0-15 cm and 15-30 cm soil temperatures,water content,and conductivity were measured simultaneously and analyzed for changes. The results showed obvious simulated temperature increases of OTC. Compared with the control without OTC,soil temperature at 0-15 cm and 15-30 cm increased by 2. 41 ℃ and 1. 27 ℃,respectively. These temperature increases resulted in 0-15 cm and 15-30 cm soil water contents increasing by 27. 65% and 32. 17% respectively. For soil conductivity at 0-15 cm and 15-30 cm,the observed values of temperature increase treatment and control were 45. 67 μS·m^-1 and 45. 75 μS·m^-1,respectively. The increase in conductivity was 158. 09% higher than the control. Correlation analysis showed that soil temperature contributed more to soil conductivity than soil moisture during soil freezing periods. Compared with the control experiment,soil water content and conductivity under simulated warming conditions showed rate increases. During the soil ablation period,a correlation between soil temperature and conductivity for the 0-15 cm and 15-30 cm soil layers increased under simulated warming,and the correlative relationship between soil water content and conductivity increased. The nature of the soil varies with depth. The correlation between soil water content and conductivity increases in the 0-15 cm soil layer,and the correlation between soil water content and conductivity in 15-30 cm soil layer is not significant. The contribution of soil temperature to soil conductivity is higher than the contribution of soil water content.