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使用LI-840便携式土壤碳通量分析仪,测定了黄土高原典型小流域砂土(风沙土)和砂质壤土(黄土)上典型藓结皮与无结皮的呼吸速率,分析两种质地土壤上藓结皮对土壤呼吸的影响。结果显示,在小时尺度上,砂土和砂质壤土上有无藓结皮的呼吸速率均呈单峰型曲线,峰值出现在14:00时,大小分别为2.49和2.66μmol·m-2·s-1;相较于无结皮,有藓结皮的两种质地土壤的呼吸速率峰值分别降低了8.6%和5.8%。在日尺度上,有藓结皮的砂土和砂质壤土的日均呼吸速率分别较无结皮降低了9.1%和5.3%,且有藓结皮的砂土日均呼吸速率比有藓结皮的砂质壤土低7.1%。此外,两种质地土壤的呼吸速率与表层2 cm土壤温度均呈显著线性相关,表明表层土壤温度是影响生物结皮土壤呼吸的主要因素;同时,藓结皮使表层土壤温度降低0.3~0.5℃,因此推测藓结皮可能会通过降低土壤温度进而影响土壤呼吸速率。研究表明,黄土高原两种质地土壤上广泛发育的藓结皮均能显著降低土壤呼吸速率,其中砂土上的藓结皮更为突出,因此在区域碳通量估算和碳循环研究中应予以充分重视。
Using LI-840 portable soil carbon flux analyzer, the typical moss crusts and non-crusting respiration rates on sandy loam (aeolian sandy soil) and sandy loam (loess) in the typical watershed of the Loess Plateau were measured. Effect of moss crust on soil respiration. The results showed that on the hourly scale, the respiration rate of moss crust on sandy soil and sandy loam showed a unimodal curve with peak values of 2.49 and 2.66 μmol · m-2 at 14:00, respectively s-1. Compared with the non-skinned and moss-crusted soil, the peak values of soil respiration decreased by 8.6% and 5.8%, respectively. On the daily scale, the average daily respiration rate of moss crust and sandy loam decreased by 9.1% and 5.3% respectively compared with no crust, and the average daily respiration rate of moss crusted sand was lower than that of moss crust Sandy loam 7.1% lower. In addition, there was a significant linear correlation between the soil respiration rate and the soil temperature of 2 cm above the surface, indicating that the surface soil temperature was the main factor affecting the soil respiration of the biological crusts. Meanwhile, the moss crust reduced the surface soil temperature by 0.3 to 0.5 ° C , Suggesting that moss crust may affect soil respiration rate by reducing soil temperature. The results show that both moss crusts developed widely on soil of Loess Plateau can significantly reduce soil respiration rate, and the moss crust on sand is more prominent, so it should be used in the estimation of carbon flux and carbon cycle in the study area Pay full attention.