Enrichment of organic compost with beneficial microorganisms and yield performance of corn and wheat /Enriquecimento de composto organico com microrganismos beneficos e desempenho produtivo do milho e trigo

• Published in: Revista brasileira de engenharia agrícola e ambiental 2021-05, Vol.25 (5), p.332
• Main Authors: Andrade, Francine C, Fernandes, Fernando, Junior, Adilson Oliveira, Rondina, Artur B.L, Hungria, Mariangela, Nogueira, Marco A
• Format: Article
• Language: Spanish
• ISSN: 1415-4366
• DOI: 10.1590/1807-1929/agriambi.v25n5p332-339

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 Dacteria, 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.sup.-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. Key words: composting, arbuscular mycorrhizal fungus, Rhizophagus clarus, Urochloa brizantha O enriquecimento com microrganismos beneficos pode aumentar os beneficios do composto organico. Este estudo teve o objetivo de avaliar o enriquecimento de um composto maturado com quatro bacterias promotoras de crescimento de plantas e fungo micorrizico (Rhizophagus clarus) usando braquiaria (Urochloa brizantha) como planta hospedeira, compreendendo sete tratamentos: controle (composto sem braquiaria, bacterias ou fungo micorrizico); composto + braquiaria; composto + braquiaria + fungo micorrizico; composto + braquiaria + fungo micorrizico + Azorhizobium sp.; composto + braquiaria + fungo micorrizico + Azoarcus sp.; composto + braquiaria + fungo micorrizico + Bacillus subtilis; e composto + braquiaria + fungo micorrizico + Azotobacter sp., em delineamento inteiramente casualizado com tres rep