The role of organic/bio-fertilizer amendment on aggregate stability and organic carbon content in different aggregate scales

This study investigated the effects of different organic and bio-fertilizer (alone or in combination) applications on aggregate stability and organic carbon (OC) content in macro (2-1 mm) and micro (0.25-0.050 mm) aggregate sizes of clay loam (Typic Xerofiuvent) textured soil. In addition, correlation between OC content and aggregate stability was determined. The study was conducted as a pot experiment under greenhouse conditions and was arranged in a completely randomized design with three replications. The treatments were: control (no fertilizer) (C), inorganic fertilizer (15:15:15 compound fertilizer + ammonium nitrate, 33% N) (F), mycorrhizal fungi (Glomus spp.) (M), microalgae (Chlorella spp.) (A), bacteria (Bacillus megaterium KBA-10 +Pantoea agglomerans RK-134 +Pseudomonasf/uorescens FDG-37) (BMF), bacteria (Bacillus subtilis PA1 +Paenibacillus azotofixans PA2) (BCP), vermicompost (V), vermicompost + mycorrhizal fungi (VM), vermicompost + microalgae (VA), vermicompost+ bacteria (VBMF) and vermicompost + bacteria (VBCP) applied in 90 days incubation period. At the end of the 90-day incubation period, organic and bio-fertilizer amendments had an increasing impact on aggregate stability and OC content in macro-and micro-aggregate scale. Especially, bio-fertilizers in combination with vermicompost mostly had stronger effects on stability and OC content of aggregates of both size classes in comparison with control and bio-fertilizer treatments alone. In addition, significant (p < 0.05) and positive correlations were observed between stability and OC contents of macro (2-1 mm) and micro (0.25-0.050 mm) aggregates size classes in each treatment. (C) 2017 Elsevier B.V. All rights reserved.