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了解果园土壤呼吸变化及其影响因素,有利于深入理解退耕还果条件下黄土高原地区土壤碳源汇功能.在长武农田生态系统国家野外站,以盛产期果园(2000年建成)为对象,利用土壤碳通量测量系统(Li-COR,Lincoln,NE,USA)于2011、2012年监测了果树冠幅下距树干不同距离处土壤呼吸、土壤水分和温度变化,分析了土壤呼吸的时空变化及其影响因素.结果表明:①土壤呼吸速率随着距树干距离延长而降低.与2 m处相比,0.5 m处土壤累积呼吸量2011年提高20%,2012年提高31%;0.5 m和2 m处土壤呼吸的温度敏感性(Q10)2011年相应依次为1.79和1.56,2012年依次为1.79和1.38.②距树干2 m处温度和水分稍高于0.5 m处,但差异不显著(P>0.05).土壤呼吸与土壤温度均呈显著的指数关系,而与土壤水分的相关性不显著.温度变化可解释土壤呼吸的季节性变化,但并不能解释距离树干不同处的差异.③距离树干不同位置处的根系密度差异是影响果园土壤呼吸空间变化及其温度敏感性的重要生物因素;④冠幅下土壤呼吸的变异系数为23%~31%.估算果园土壤呼吸需考虑其距离树干的空间差异性.
Knowing the change of soil respiration in orchards and its influencing factors is conducive to a deeper understanding of soil carbon sink function in the Loess Plateau Rehabilitation Project.On the field station of Changwu farmland ecosystem in the rich orchard (built in 2000) Changes of soil respiration, soil moisture and temperature at different distances from tree trunks were monitored using a soil carbon flux measurement system (Li-COR, Lincoln, NE, USA) in 2011 and 2012. Spatio-temporal variations of soil respiration The results showed that: (1) The soil respiration rate decreased with the distance from the trunk, and the accumulated soil respiration at 0.5 m increased by 20% in 2011 and 31% in 2012 compared with 2 m, 0.5 m and The temperature sensitivities of soil respiration at 2 m (Q10) were 1.79 and 1.56 in 2011, followed by 1.79 and 1.38 in 2012. ② The temperature and water at 2 m from the trunk were slightly higher than 0.5 m with no significant difference P> 0.05) .And soil respiration had a significant exponential relationship with soil temperature, but no significant correlation with soil moisture.Changes in temperature explained the seasonal changes of soil respiration, but did not explain the differences at different distances from the trunk.③ Different location from the trunk Of root system density is an important biological factor that affects soil respiration spatial variability and temperature sensitivity in orchard soil; ④The coefficient of variation of soil respiration under crown amplitude is 23% ~ 31% .To estimate orchard soil respiration, .