黑河下游五种不同植被类型土壤呼吸的差异性解析

Analytic differences on soil respiration of various vegetation types in the lower reaches of Heihe River Basin

土壤呼吸的微小变化会对大气CO_2浓度产生重大影响,尤其在极端干旱区。通过对黑河下游额济纳旗四道桥的混合林、胡杨、柽柳、农田及裸地的土壤呼吸进行研究,结果表明:2014年夏季5种不同植被类型的土壤呼吸速率大小排序:胡杨柽柳混合林>柽柳>农田>胡杨>裸地,各类型的5 cm处土壤温度和湿度无明显变化规律,土壤温度在22~35℃,土壤湿度集中在13%~61%的变化范围。探究了5种不同植被类型的土壤呼吸速率与土壤温度、土壤湿度、地表温度、空气温度及空气湿度的线性相关关系,发现它们的土壤呼吸速率与土壤温度、土壤湿度、空气温度、空气湿度之间无显著相关(P>0.05),表明水热因子对土壤呼吸的影响具有很大的不确定性。

Slight changes in soil respiration can have significant impacts on atmospheric CO2 concentrations, es- pecially in extreme arid regions. In this paper, the soil respiration of different vegetation cover types, including forest （Populus euphratica）, shrub （Tamarix chinensis）, mixed forest （Populus euphratica mixed with Tamarix chinensis） , farmland and bare soil were measured at Sidaoqiao, Ejin County, Inner Mongolia, China in lower reaches of Heihe River during the summer of 2014. Results indicated that soil respiration rate for the five differ- ent vegetation types were descending ordered： Mixed forest〉 T. chinensis〉Farmland〉P, euphratica 〉 Bare land. The soil temperature and soil moisture at 5 cm changed insignificantly, soil moisture ranging from 13% to 61% with soil temperature varying from 22 to 35 ℃ （there was a rain during the experiment period）. The linear rela- tionships between soil respiration and environmental factors including soil temperature, soil moisture, surface temperature, air temperature and air humidity of five different types vegetation were explored. It was found that there was no significant correlation （P〉 0.05 ） between the four environmental factors. Besides, the effects of hy- drothermal factors on soil respiration were with high uncertainty. The results could provide scientific support and basic data for the study of the changes of soil respiration and carbon cycle in desert riparian forest. In the future, we need to deeply analyze the impact mechanism of hydrothermal factors on soil respiration in the extreme arid area.