Impact of diurnal unsymmetrical warming on soil respiration in an agroecological system of the Lhasa region

Purpose
The impact of diurnal unsymmetrical rise in temperature on soil respiration (Rs) is not fully understood; thus, we explored such a warming influence on Rs in an agroecological system of the Lhasa.
Materials and methods
A field warming experiment (C: control; DW: daytime warming; NW: nighttime warming; DW+NW: daytime plus nighttime warming) was carried out in a naked barley ecological system.
Results and discussion
The DW, NW and DW+NW treatments dramatically increased soil temperature and decreased soil moisture but did not markedly modify Rs. The effects of DW and NW on soil respiration sensitivity (Q10) during the daytime and nighttime were different; they had no effects on daytime Q10 of Rs, but a significant inhibitory effect on nighttime Q10 of Rs.
Conclusions
A diurnal unsymmetrical rise in temperature brought about different results for the Q10 of Rs but did not cause changes in Rs under different experimental treatments in agroecological systems of the Lhasa.

研究背景与目的
昼夜非对称升温对土壤呼吸（soil respiration，Rs）的影响尚未得到充分阐明，因此我们在拉萨的农田生态系统中探究了此类增温对土壤呼吸的作用。
材料与方法
本研究在裸大麦农田生态系统中开展野外增温实验，设置4组处理：对照组（control，C）、日间增温组（daytime warming，DW）、夜间增温组（nighttime warming，NW）以及昼夜同时增温组（daytime plus nighttime warming，DW+NW）。
结果与讨论
日间增温、夜间增温和昼夜同时增温处理均显著提升了土壤温度，同时降低了土壤含水量，但未显著改变土壤呼吸。日间增温和夜间增温对土壤呼吸温度敏感性（Q10）的昼夜效应存在差异：二者均未对土壤呼吸的日间Q10产生显著影响，但对土壤呼吸的夜间Q10具有显著的抑制效应。
结论
在拉萨的农田生态系统中，昼夜非对称升温会对土壤呼吸的Q10产生差异化影响，但本实验的不同增温处理均未引起土壤呼吸水平的显著变化。