Feng Wei, Zhang Yu-qing, Wu Bin, Zha Tian-shan, Jia Xin, Qin Shu-gao, Shao Chen-xi, Liu Jia-bin, Lai Zong-rui, Fa Ke-yu
Yanchi Research Station, College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
ScientificWorldJournal. 2013 Dec 18;2013:408560. doi: 10.1155/2013/408560. eCollection 2013.
Soil respiration (Rs) is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer. We measured Rs in three types of disturbed and undisturbed crusted soils (algae, lichen, and moss), as well as bare land from April to August, 2010, in Mu Us desert, northwest China. Rs was similar among undisturbed soils but increased significantly in disturbed moss and algae crusted soils. The variation of Rs in undisturbed and disturbed soil was related to soil bulk density. Disturbance also led to changes in soil organic carbon and fine particles contents, including declines of 60-70% in surface soil C and N, relative to predisturbance values. Once BSCs were disturbed, Q 10 increased. Our findings indicate that a loss of BSCs cover will lead to greater soil C loss through respiration. Given these results, understanding the disturbance sensitivity impact on Rs could be helpful to modify soil management practices which promote carbon sequestration.
土壤呼吸（Rs）是碳循环的主要途径，是一个涉及非生物和生物因素的复杂过程。生物土壤结皮（BSCs）是全球沙漠生态系统的关键生物组成部分。在沙漠生态系统中，土壤受到生物土壤结皮的保护而免受地表干扰，但尚不清楚土壤呼吸是否会受到这种结皮层干扰的影响。2010年4月至8月，我们在中国西北毛乌素沙漠测量了三种受干扰和未受干扰的结皮土壤（藻类、地衣和苔藓）以及裸地的土壤呼吸。未受干扰的土壤中土壤呼吸相似，但在受干扰的苔藓和藻类结皮土壤中显著增加。未受干扰和受干扰土壤中土壤呼吸的变化与土壤容重有关。干扰还导致土壤有机碳和细颗粒含量的变化，包括表层土壤碳和氮相对于干扰前值下降60-70%。一旦生物土壤结皮受到干扰，Q10增加。我们的研究结果表明，生物土壤结皮覆盖的丧失将导致通过呼吸作用造成更大的土壤碳损失。基于这些结果，了解干扰敏感性对土壤呼吸的影响可能有助于改进促进碳固存的土壤管理措施。
