The distribution of soil microbial parameters based on aggregate fractions in successional grassland restoration ecosystems on the Loess Plateau

Abstract

Soil microbial biomass and microbial metabolic quotients have been identified as the most effective indicators of a response to ecosystem development and disturbance. In order to determine the effects of grassland restoration programs, we analyzed the distribution of soil microbial parameters in different aggregate fractions at 1 yr. (1 year), 10 yr. (10 years) and 30 yr (30 years). Results show that Cmic (soil microbial biomass carbon) and Pmic (soil microbial biomass phosphorus) increased with grassland succession, the greatest values were concentrated at a micro-aggregate size. However, qCO2 (soil microbial metabolic quotient) decreased as the years under restoration increased. qCO2 was significantly correlated with SOC (soil organic carbon), TN (soil total nitrogen), Pmic (negatively) and Cmic (positively). Natural succession of grassland alters soil microbial properties positively, which plays a major role in aggregate formation. The time under vegetation rehabilitation impacts soil microbial parameters at different aggregate sizes, macro-aggregate size is the key factor in soil stability improvement in the process of natural restoration, especially for the aggregate size of 2–3 mm.