Effect of lime application on soil respiration is modulated by understory vegetation in subtropical Eucalyptus L'Her. plantations

ObjectiveLime application and understory plant clearance are two common forest management methods employed to increase forest productivity in subtropical regions. However, the effect of these two management methods, or their combined application, on soil respiration in forest plantation settings is still not fully understood. MethodsHere, a field experiment was conducted to determine how lime application, understory clearance, and their combined application, would impact total soil respiration (R-s), autotrophic respiration (R-a), and heterotrophic respiration (R-h) in a Chinese subtropical Eucalyptus plantation. Changes in soil microclimate and microbial community (PLFAs), as well as Eucalyptus fine root biomass were also assessed. ResultsLime application stimulated R-h, but decreased R-a of understory vegetation (primarily Dicranopteris dichotoma), thus consequently inhibiting R-s. Understory clearance also reduced R-s, primarily due to reductions in soil PLFAs and associated R-h, and R-a of understory vegetation. Since the increase in R-h induced by lime application was greater than the decrease in R-h caused by understory clearance, the combined application of lime application and understory clearance decreased R-s primarily by reducing understory root respiration. ConclusionOur observations suggest that understory plants can modulate the effect of lime application on R-s, highlighting the important role of understory vegetation in regulating soil carbon cycling in subtropical Eucalyptus plantations. We concluded that the potential interactive effects should be considered in developing management practices that optimize the yield and sustainability of subtropical plantations.