Effects of liming on soil respiration and its sensitivity to temperature in Cunninghamia lanceolata plantations.

Abstract

The primary distribution area of acid deposition coincides with areas of Chinese fir (Cunninghamia lanceolata) plantations. Liming is an effective method of restoring acidified soil. To understand the effects of liming on soil respiration and temperature sensitivity within the context of acid deposition, we measured soil respiration and its components in Chinese fir plantations for one year beginning in June 2020, with 0, 1 and 5 t·hm-2 calcium oxide being added in 2018. The results showed that liming considerably increased soil pH and exchangeable Ca2+ concentration, and that there was no significant difference among different levels of lime application. Soil respiration rate and components in the Chinese fir plantations exhibited seasonal variations, with the highest values during the summer and the lowest values during the winter. Although liming did not alter seasonal dynamics, it strongly inhibited heterotrophic respiration rate and increased autotrophic respiration rate of soil, with minor effect on total soil respiration. The monthly dynamics of soil respiration and temperature were largely consistent. There was a clear exponential relationship between soil respiration and soil temperature. Liming increased temperature sensitivity Q10 of soil respiration and autotrophic respiration but reduced that of soil heterotrophic respiration. In conclusion, liming promoted soil autotrophic respiration and strongly inhibited soil heterotrophic respiration in Chinese fir plantations, which would facilitate soil carbon sequestration.