Abstract: Aims Slash removal is a common practice to prepare recently harvested sites for replanting. However, little is known about its impact on soil carbon (C) dynamics in subtropical plantations. This study evaluates the effects of burning versus manual slash removal site preparation treatments on soil organic carbon (SOC), soil respiration and soil microbial community structure in a Pinus massoniana plantation in southern China.
Methods Three areas within a mature P. massoniana plantation were clearcut. Two months following harvesting, slash on one-half of each area was burned (BURN), whereas slash was manually removed (MANR) on the other portion. Slash removal treatments were also compared with adjacent uncut plantation areas (UNCUT). Soil samples, and soil respiration measurements were used to characterize soil properties and microbial communities following slash removal treatments.
Important findings Mean soil respiration rates from the MANR and BURN treatments were 26% and 17% lower, respectively, than the UNCUT treatment over 1 year. The MANR and BURN treatment resulted in soils with 27% and 9% reduction in total phospholipid fatty acids (PLFAs) and 18% and 10% reduction in bacterial PLFAs, respectively, compared with the UNCUT treatment. However, no significant differences existed between slash removal treatments with respect to soil chemical properties, SOC chemical compositions, soil respiration and microbial communities; although PLFA patterns were notably different for the burned plots. Most factors affecting C dynamics and microbial communities were not sensitive to the differences imparted to the ecosystem due to manual slash removal or burning. Our results suggested that low-intensity burning after clear-cutting might have no significant effect on soil C pool and its dynamics compared with manual slash removal in subtropical plantations.

Key words: plantation management, soil organic carbon, chemical composition, soil respiration, soil microbial community, fire