Changes in soil aggregation and microbial community structure control carbon sequestration after afforestation of semiarid shrublands

摘要: Abstract Changes in plant cover after afforestation induce variations litter inputs and soil microbial community structure activity, which may promote the accrual physical-chemical protection of organic carbon (SOC) within aggregates. In a long-term experiment (20 years) we have studied effects, on aggregation SOC stabilization, two techniques: a) amended terraces with refuse (AT), b) without amendment (T). We used adjacent shrubland (S) as control. Twenty years stand establishment, aggregate distribution (including microaggregates larger aggregates), sensitive slow (OC) fractions, basal respiration macroaggregates, were measured. The main changes occurred top layer (0–5 cm), where: i) both OC fractions increased AT compared to S T, ii) percentage content macroaggregates (Mm) higher than iii) was also AT, iv) significant fungal (rather bacterial) observed afforested soils (AT T) – soil. These results suggest that increase pools linked activity structure, afforestation, promoted formation acted nucleus for stabilization OC-enriched microaggregates.