Zhang Yan-Jun
Key Laboratory of Disaster Monitoring and Mechanism Simulation, Baoji University of Arts and Sciences, Baoji 721013, China.
College of Geography and Environmental Engineering, Baoji University of Arts and Sciences, Baoji 721013, China.
Huan Jing Ke Xue. 2017 Aug 8;38(8):3497-3506. doi: 10.13227/j.hjkx.201612097.
Surface litter respiration is a major component of soil respiration in the carbon cycle of terrestrial ecosystems, and studying the variation in the temperature sensitivity of surface litter respiration and its influencing factors is important for the accurate understanding of the regional soil carbon cycle. In a typical locust plantation ( L.) ecosystem in a small watershed in Wang Donggou of Loess Plateau, China, three surface litter control treatments were established: ① control treatment, ② litter removal treatment, and ③ doubled litter treatment, for studying the interannual variation (2009-2013) in the temperature sensitivity of surface litter respiration and its influencing factors. The interannual variability in the temperature sensitivity of surface litter respiration was statistically significant (<0.05). It ranged from 4.15 in 2012 to 6.67 in 2010, with mean value of 5.10 and a coefficient of variation of 19% in the control treatment, and from 1.77 to 6.52, with mean value of 3.36 and a coefficient of variation of 56% in the doubled litter treatment. It was closely related with annual surface litter biomass, annual mean soil moisture content, and the interplay between annual surface litter biomass and annual mean soil moisture content (<0.01). Moreover, the contribution to temperature sensitivity of surface litter respiration from soil moisture was greater than that from surface litter biomass (control treatment: 2.68 vs. 2.04, respectively; doubled litter treatment: 1.37 vs. 0.69, respectively). Additionally, under the doubled litter treatment, temperature sensitivity of surface litter respiration decreased by 34%. In the artificial locust plantation ecosystem, over 50% of surface litter carbon was kept under the control treatment [215 g·(m·a) vs. 113 g·(m·a)], but only 24% of surface litter carbon was kept under the doubled litter treatment [430 g·(m·a) vs. 326 g·(m·a)], which implied that the soil carbon reserves in the plantation ecosystem will not increase with an increase of surface litter biomass in the Loess Plateau, China. Therefore, investigating the relationships among soil moisture, surface litter biomass, and surface litter biomass control measures are useful for the accurate understanding of the regional soil carbon cycle.
地表凋落物呼吸是陆地生态系统碳循环中土壤呼吸的主要组成部分，研究地表凋落物呼吸温度敏感性的变化及其影响因素对于准确理解区域土壤碳循环具有重要意义。在中国黄土高原王东沟小流域典型的刺槐人工林生态系统中，设置了三种地表凋落物控制处理：①对照处理；②去除凋落物处理；③加倍凋落物处理，以研究地表凋落物呼吸温度敏感性及其影响因素的年际变化（2009—2013年）。地表凋落物呼吸温度敏感性的年际变异性具有统计学意义（<0.05）。在对照处理中，其范围为2012年的4.15至2010年的6.67，平均值为5.10，变异系数为19%；在加倍凋落物处理中，范围为1.77至6.52，平均值为3.36，变异系数为56%。它与年地表凋落物生物量、年平均土壤含水量以及年地表凋落物生物量与年平均土壤含水量之间的相互作用密切相关（<0.01）。此外，土壤水分对地表凋落物呼吸温度敏感性的贡献大于地表凋落物生物量（对照处理分别为2.68和2.04；加倍凋落物处理分别为1.37和0.69）。此外，在加倍凋落物处理下，地表凋落物呼吸温度敏感性下降了34%。在人工刺槐林生态系统中，对照处理下超过50%的地表凋落物碳被保留[215 g·(m·a)对113 g·(m·a)]，但加倍凋落物处理下仅24%的地表凋落物碳被保留[430 g·(m·a)对326 g·(m·a)]，这意味着在中国黄土高原，人工林生态系统中的土壤碳储量不会随着地表凋落物生物量的增加而增加。因此，研究土壤水分、地表凋落物生物量和地表凋落物生物量控制措施之间的关系有助于准确理解区域土壤碳循环。
