Dados do Trabalho

Título

THE POTENTIAL OF NITROGEN-FIXING BACTERIA ISOLATES FROM VOLCANIC DEPOSITS OF THE LLAIMA VOLCANO OF CHILE IN AGRICULTURAL SOIL NITROGEN-FIXATION

Resumo

Global food production systems are calling for deep changes. At the early 2023 FAO, published its statistical report “Food and Agriculture”, which informed the use of inorganic fertilizers reached 200 million tonnes at the 2020, of which 56% correspond to nitrogen (N) fertilizers. Due to its low use efficiency, around 50-60% of N is mainly losses, leading to disruptions in the N biochemical cycle as well as environmental impact. A natural process to input soil N is the biological N fixation (BNF), leaded by bacteria N fixers or diazotrophs which involves the reduction of N2 to NH4+. The aims of this work were to isolate N-fixing bacteria from soil-formation of volcanic deposits of Llaima Volcano eruption at 1751 and to evaluate their potential for biofertilizer development. Soil samples were collected in formation in volcanic deposits in the Chilean Conguillio National Park for bacteria isolation. Four N-free cultures medium (LGI, JNFb, Baz and RM) were used to carried out the isolation according to reported by Baldai et., (2014). To evaluate its potential for biofertilizer application Plant Grow Promoting Bacteria (PGPB) activities were evaluated. A total of 33 bacteria isolates was obtained, which 16 from JNFb and 17 from RM medium. PGPB results report 21 isolated with indole acetic acid activity, 20 isolates with phosphate solubilization activity and 9 isolates shown sulphur oxidation. Better PGPB activities were observed in bacteria isolates from JNFb medium, from which 8 bacteria isolates were selected based on their excellent PGPB capacities. Then, to evaluate their soil N-fixing capacity, 4 weeks of soil incubation were carried out, evidencing that two isolates JN4 and JN5 increase the soil fixed N ~ 10% respect to the soil, showing a higher capacity than the positive control Azospirillum oryzae Coc8. Preliminary results allow us to demonstrate a great potential of these two bacteria isolates for the development of N biofertilizers.

Palavras-chave

biological nitrogen fixation; food production; diazotrophs; smart climate agriculture; N fertilizers

Instituição financiadora

Agencia Nacional de Investigación y Desarrollo de Chile (ANID)

Agradecimentos

To ANID/FONDECYT Regular project N° 1201375