Effects of litter treatments on soil respiration of Pinus armandii plantation

The aim of this study was to investigate the effects of litter addition and removal on soil respiration rate, in order to provide the theoretical basis for soil carbon pool management of plantation.

Pinus armandii plantation in Shennongjia was taken as the research object. The soil respiration rate (R_s), soil temperature and soil water content were determined with Li-8100A soil carbon flux measurement system from April 2021 to March 2022, and the effects of litter treatment on R_s were studied by setting up three treatments: control (CK), litter removal (LR) and litter addition (LA).

1) There was no significant difference in soil temperature and soil moisture content among the three treatments (P > 0.05). The R_s was consistent with the trend of soil temperature, the maximum value appeared in July and the minimum value appeared in February; 2) The average value of R_s of the three treatments was LA (2.17 μmol·m^-2·s^-1) > CK (1.69 μmol·m^-2·s^-1) > LR (1.25 μmol·m^-2·s^-1), the R_s was lower by 26.02% with LR than that of CK; while the R_s was higher by 29.48% with LA than that of CK; 3) A significant positively correlation was found between R_s and the soil temperature under different litter treatments (P < 0.01). Soil temperature explained 97.31%, 99.18% and 95.37% variation of soil respiration rate under CK, LR and LA treatments respectively. The correlation between soil respiration rate and soil water content was not significant (P > 0.05), and soil temperature was the main influencing factor of soil respiration in P. armandii plantation; 4) The soil respiration temperature sensitivity index (Q₁₀) under three treatments was CK (2.98) > LR (2.91) > LA (2.88), both litter removal and litter addition decreased soil temperature sensitivity.

The change of litter input has an important impact on soil respiration rate, and different treatment methods have different effects on soil respiration.