单 位：
甘肃民勤荒漠草地生态系统国家野外科学观测研究站;甘肃省治沙研究所甘肃省荒漠化与风沙灾害防治国家重点实验室培育基地
关键词：
白刺;灌丛沙堆;土壤呼吸;空间异质性;日动态
摘 要：
[目的]对干旱区白刺灌丛沙堆不同生育期土壤呼吸空间异质性进行研究,为今后估算绿洲荒漠区土壤CO2排放量以及区域碳收支状况提供科学依据。[方法]利用Li-8100土壤呼吸测定系统,于2014年在巴丹吉林沙漠南缘绿洲—荒漠过渡带对白刺灌丛沙堆不同部位的土壤呼吸速率进行野外观测,分析沙堆上不同位点土壤呼吸日动态变化、不同生长时期的季节变化特征。[结果](1)白刺灌丛沙堆在不同生长时期各部位土壤呼吸日动态变化曲线不同,生长初期和生长休眠期各部位日变化呈"单峰"曲线变化,在生长旺盛期各部位变化既有"单峰"曲线又有"双峰"曲线;同时,日变化峰值出现的时间不一致:生长初期各位点的峰值出现在上午11:00左右,旺盛期上午出现在10:00前后,下午出现在17:00左右,休眠期出现在下午14:00前后。(2)沙堆上不同部位土壤呼吸速率具有时空异质性,生长初期和休眠期各部位土壤呼吸速率异质性不显著(p>0.05),旺盛期各部位空间差异显著(p<0.01),异质性增强;沙堆各时期平均土壤呼吸速率差异显著(p<0.01),大小排序为:旺盛期>生长初期>生长休眠期。[结论]白刺灌丛沙堆上不同部位的土壤呼吸速率日动态变化在不同的生长时期表现不同,具有明显的时空异质性,主要是沙堆不同部位近地表层大气水分条件、土壤20cm深处的温度和水分含量的差异共同作用导致了各个位点土壤呼吸通量具有明显的差异性。
译 名：
Spatial Heterogeneity of Soil Respiration of Nitraria Tangutorum Nebkhas During Different Growing Period in Arid Areas
作 者：
SUN Tao;HAN Fugui;GUO Shujiang;DUAN Xiaofeng;ZHANG Yunian;Gansu Desert Control Research Institute,State Key Laboratory of Desertification and Aeolian Sand Disaster Combating;Minqin National Research Station for Desert Steppe Ecosystem;
关键词：
Nitraria tangutorum;;nabkhas;;soil respiration;;spatial heterogeneity;;daily change
摘 要：
[Objective]The spatial heterogeneity of soil respiration in different growing period of Nitraria tangutorumin dryland was demonstrated to provide a scientific basis for the estimation of CO2 emission and for the regional carbon budget in oasis.[Methods]Using Li-8100 soil respiration measurement system,we made field observation of soil respiration rate of Nitraria tangutorum nebkhas dominated dunes in 2014.The dunes located in the oasis-desert ecotone on the southern fringe of Badanjara Desert.We measured the daily change at different positions of Nitraria tangutorum along growing period,and studied the spatial heterogeneity of soil respiration of Nitraria tangutorum at different position and their seasonal variability.[Results](1)The daily change of soil respiration rate of Nitraria tangutorum at different positions and in different growing period were different.It exhibited an unimodal variation both at the beginning of the growing period and at the dormancy season.In flourishing period,both unimodal and bimodal existed for daily respiration.Besides that,the peaks of soil respiration in different growth periods were different:the peak occurred ataround 11:00in beginning growth period,the peak of the flourishing period occurred at around 10:00or17:00.The peak in dormancy period delayed and occurred at 14:00.(2)There was different spatial heterogeneity of soil respiration rate at different positions on the sand mound.No significant difference(p>0.05)existed for the observations at different dune positions at the beginning of the growing period and at the dormancy period.Whereas there was a significant spatial difference(p<0.01)at the flourishing period.The average soil respiration rate at different growing period varied significantly,had a rank of flourishing period>beginning of the growing period>dormancy period.[Conclusion]Soil respiration rate of Nitraria tangutorum at different positions and in different growing period showed significantly spatial heterogeneity,which was mainly resulted from the interaction of near-surface water condition,the temperature and water content above 20 cm soil of Nitraria tangutorum at different positions.
