Maize is among the most important crops in the world. This plant species can be colonized by diazotrophic bacteria able to convert atmospheric N into ammonium under natural conditions. This study aimed to investigate the effect of inoculation of the diazotrophic bacterium Herbaspirillum seropedicae (ZAE94) and isolate new strains of plant growth-promoting bacteria in maize grown in Vitória da Conquista, Bahia, Brazil. The study was conducted in a greenhouse at the Experimental Area of the Universidade Estadual do Sudoeste da Bahia. Inoculation was performed with peat substrate, with and without inoculation containing strain ZAE94 of H. seropedicae and four rates of N, in the form of ammonium sulfate (0, 60, 100, and 140 kg ha -1 N). After 45 days, plant height, dry matter accumulation in shoots, percentage of N, and total N (NTotal) were evaluated. The bacteria were isolated from root and shoot fragments of the absolute control; the technique of the most probable number and identification of bacteria were used. The new isolates were physiologically characterized for production of indole acetic acid (IAA) and nitrogenase activity. We obtained 30 isolates from maize plants. Inoculation with strain ZAE94 promoted an increase of 14.3 % in shoot dry mass and of 44.3 % in NTotal when associated with the rate 60 kg ha -1 N. The strains N11 and N13 performed best with regard to IAA production and J06, J08, J10, and N15 stood out in acetylene reduction activity, demonstrating potential for inoculation of maize.

A B S T R A C TThis work aimed to evaluate the influence of green fertilization and the compost on the production of radish, cv. 'Cometa' . The experimental design was randomized blocks with 6 treatments and 4 replicates: T1 -Leucaena, T2 -'Madeira-nova' , T3 -Compost (maize straw and composted cattle manure), T4 -'Sempre verde' grass + compost and T5 -'Sempre verde' grass and T6 -control without fertilization, totaling 24 experimental plots. The total area of the experimental plot was 1.44 m 2 , with useful area of 0.80 m 2 and 21.0 t ha -1 of fertilizer (dry basis) were incorporated in each treatment. The radish crop was directly sown in the beds, in 2-to 3-cm-deep holes, leaving one plant at spacing of 20 cm between rows and 5 cm between plants. Twenty-nine days after planting, plants were evaluated for total yield, commercial yield, percentages of commercial roots (%) and waste roots (%), fresh and dry matter of shoots and roots, total and individual leaf area and the SPAD index. The incorporation of Leucaena at the amount of 21.0 t ha -1 (dry basis) promoted the highest increments for the analyzed characteristics.Uso de coberturas mortas e seus efeitos para cultura do rabanete R E S U M O Objetivou-se, neste estudo, avaliar a influência da adubação verde e do composto na produção do rabanete cv. Cometa. O delineamento experimental adotado foi em blocos casualizados com 6 tratamentos e 4 repetições sendo T1 -Leucena, T2 -Madeira-nova, T3 -composto (palha de milho e esterco bovino compostado), T4 -capim sempre verde + palha de milho e esterco bovino compostado e T5 -capim sempre verde e T6 -testemunha sem adubação totalizando 24 parcelas experimentais. A área total da parcela experimental foi de 1,44 m 2 , com área útil de 0,80 m 2 e para cada tratamento foram incorporadas 21,0 t ha -1 de adubo em base seca. A semeadura do rabanete foi diretamente nos canteiros em berços de 2 a 3 cm de profundidade deixando uma planta no espaçamento de 20 cm entre linhas e 5 cm entre plantas; aos 29 dias após plantio foram avaliados a produtividade total, produtividade comercial, a porcentagem de raízes comercial (%) e de refugo (%), massa fresca e seca da parte aérea e das raízes, área foliar total e individual e o índice SPAD. A incorporação da leucaena na quantidade de 21,0 t ha -1 em base seca ao solo proporcionou os maiores acréscimos para as características analisadas.