Soil organic carbon, nitrogen and microbial properties in contrasting forest ecosystems of north-east China under different regeneration scenarios

Abstract

We compared soil organic carbon (SOC), nitrogen (N), and microbial populations and biomass in a natural Pinus koraiensis forest, a secondary (regenerated) forest, and P. koraiensis and Larix gmelinii plantations in Liangshui Nature Reserve, northeast China. Surface SOC, total N and microbial populations and biomass from the P. koraiensis plantation were significantly lower compared to natural and regenerated forests. Although surface SOC from the L. gmelinii plantation was not significantly different from either the natural and secondary forests, surface soil microbial populations and biomass from the L. gmelinii plantation were significantly lower. Differences among sites became less pronounced in subsoils (10Á20 and 20Á30 cm). There were positive and significant correlations between SOC, total N and microbial populations and biomass.The study showed that the tested soil characteristics, both abiotic and biological, from a naturally regenerated forest were more similar to those of an intact, natural forest, than either of the plantations. The P. koraiensis plantation demonstrated more impacts (e.g., lower microbial densities and reduced SOC) than the L. gmelinii plantation. Soil microbial properties appeared to be more sensitive than SOC or total N as indicators of damage to the soil microcosm.Keywords: Natural Pinus koraiensis and natural regeneration forests, Pinus koraiensis and Larix gmelinii plantations, soil organic carbon and total nitrogen, microbial populations and biomass.