Abstract

The objective of this study was to improve rice and maize yields using native Azospirillum-based biofertilizer. To reach this objective, samples of rhizosphere soil, non-rhizosphere soil and roots of maize plants were collected from the particular locations of Samanko and Bamako of the south Mali. Thirty-three different colonies of bacteria were isolated from the different samples. Based on their better growth in nitrogen free semi-solid medium, their morphological, biochemical and plant growth promotion characteristic, ten bacterial isolates were identified as Azospirillum isolates following the Bergey’s Manual of Determinative Bacteriology. Ten isolates were selected: Az1, Az2, Az3, Az4, Az5, Az6, Az7, Az8, Az9 and Az10. Strain Az6 showed great potential on both rice and maize production. Therefore, this strain is suggested for large scale rice and maize fields’ application. While the Azospirillum sp. Az5, Az6 and Az10 strains are suggested for large scale application in maize field, which may reduce production cost. Top dressing with 25% of the recommended nitrogen-fertilizer was found to decrease maize grain yield.

Key words: Azospirillum, Nitrogen-fixing bacteria, plant growth-promoting rhizobacteria (PGPR), biopesticide, maize, rice, Mali.