Enrichment of organic compost with beneficial microorganisms and yield performance of corn and wheat

Abstract

Enrichment with beneficial microorganisms may increase the benefits of organic compost. The aim of this study was to evaluate the enrichment of a mature compost with plant growth-promoting bacteria and arbuscular mycorrhizal fungus (Rhizophagus clarus), using brachiaria (Urochloa brizantha) as host plant, totaling seven treatments: control (compost with no bacteria, brachiaria or mycorrhizal fungus); compost + brachiaria; compost + brachiaria + mycorrhizal fungus; compost + brachiaria + mycorrhizal fungus + Azorhizobium sp.; compost + brachiaria + mycorrhizal fungus + Azoarcus sp.; compost + brachiaria + mycorrhizal fungus + Bacillus subtilis; and compost + brachiaria + mycorrhizal fungus + Azotobacter sp., in a completely randomized design with three replicates. Brachiaria shoot biomass, N and P concentrations, mycorrhizal colonization, and chemical characteristics of the compost were assessed five times over 183 days. B. subtilis and Azotobacter increased ammonium-N concentration in the compost in two and three sampling dates, respectively. In contrast, Azotobacter and Azoarcus decreased the concentrations of nitrate-N in at least one sampling. Despite high P availability in the compost (951-2927 mg kg-1), mycorrhizal colonization reached up to 53%. In a field trial with the produced composts, in a randomized block design with six repetitions, the composts with brachiaria doubled the mycorrhizal colonization of corn (Zea mays) and wheat (Triticum aestivum), independent of the growth-promoting bacteria and, depending on the associated bacteria, increased grain yields.

Potential of Compost Enriched with Bacillus velezensis B-27 and Bacillus cereus RC76 for the Management of Twisted Disease on Shallots

“…Recently, a combination of microbes and compost has also been studied in the management of diseases caused by Fusarium (Fu et al, 2016(Fu et al, , 2017Huang et al, 2019). Enrichment of compost with beneficial microbes is carried out as an effort to increase the benefits of compost in increasing soil fertility (Andrade et al, 2021). Fengycin suppresses mycelium growth of the pathogenic fungus F. solani that causes basal stem rot disease in passion fruit plants.…”