踩踏对亚热带沟叶结缕草草坪冬季休眠期土壤呼吸的影响

随着城市化进程加快,城市绿地也在迅速扩张,人为踩踏是城市绿地重要干扰因素,其可能对草坪土壤呼吸产生显著影响,进而影响城市草坪碳循环。因此,在典型亚热带沟叶结缕草草坪内选取人为踩踏和对照处理,采用Li-8100土壤碳通量分析仪对冬季结缕草草坪土壤呼吸速率进行动态连续测定。结果表明,亚热带沟叶结缕草草坪冬季休眠期土壤呼吸动态呈单峰曲线,先降低后升高;人为踩踏显著降低了沟叶结缕草草坪休眠期土壤呼吸速率和土壤呼吸温度敏感性(Q₁₀);休眠期土壤呼吸速率主要受温度控制,而与土壤水分无关;试验期间,踩踏平均使土壤呼吸速率下降53.6%;踩踏引发的土壤物理特性和植物生长的变化综合作用而导致沟叶结缕草草坪土壤呼吸速率下调。

Effects of stepping on soil respiration of Zoysia matrella lawn during the winter dormancy period

With the acceleration of urbanization, urban green areas are rapidly expanding. Human stepping is one of the important disturbances impacting on urban green space and may affect the soil respiration and carbon cycle of lawns. Therefore, we choose stepping and control plots in a typical subtropical Zoysia matrella lawn. Soil respiration rates were continuously measured during the winter dormant period using a Li-8100 automatic instrument. Seasonal variations in soil respiration was characterized by a pattern of mono-peak curves, initially decreasing but then increasing. Human stepping significantly reduced the soil respiration rate and temperature sensitivity of soil respiration (Q₁₀) in the Z. matrella lawn during the period of dormancy. Soil respiration of Z. matrella lawn was controlled more by soil temperature than soil moisture over the dormant period. Stepping reduced soil respiration rate of Z. matrella lawn by 53.6% on average. Stepping-induced changes in soil physical properties and growth of Z. matrella might interactively cause the decline in soil respiration.