Dados do Trabalho

Título

SMART N FERTILIZER POTENTIAL TO INCREASE SOIL C SEQUESTRATION

Resumo

Our world is currently facing a crisis, two planetary boundaries have been surpassed by human activities, where agriculture has been the major driver of their transgression. Diazotrophic bacteria has attracted attention as an alternative to develop smart fertilizer, due to being capable to convert N-atmospheric into ammonia, which can be used by plants. The aims of this study were to develop a bacteria consortium microencapsulated to promote the biological N-fixing (BNF) and, to evaluate two C-rich carrier materials on foster terrestrial C sequestration and stabilization for the smart fertilizer development. Soil incubations were conducted for 8 weeks to evaluate the BNF capacity. Total N content was digested through sulfuric acid Kjeldahl method and determined by spectrophotometry at 425 nm using Nessler's reagent. To evaluate the C dynamic of two C-rich carrier materials (composted wheat straw and spent mushroom substrate), one-year soil decomposition experiments were conducted to determine C release and storage, with two levels of carrier materials input low and high-rate incorporation in order to increase 1 g and 0.5 g of soil C. Results reported that bacteria consortium microencapsulated (CMC) seems to be the best alternative for BNF able to fix ~1 g N per 1 kg of soil up to 60 days. The C dynamic showed that cumulative carbon dioxide emission increased with C-rich residue amendments at low and high rate incorporation up to 120 to 1340 mg CO2 (100 g soil)-1, being composted wheat straw at high rate incorporation with the major emission. Respiration analysis reports a low total C loss from the different treatment between 3 to 5.9 % of the initial C, suggesting C stabilization.  Finally, the C-rich carrier materials and CMC could be a great alternative for smart fertilizers engineering with the potential to increase C sequestration and fix around 1.7-ton N ha-1 in an Andisol with a density around 0.85 kg/m3 at 20 cm depth.

Palavras-chave

Food security; climate change; soil microorganisms; agrucultural waste

Instituição financiadora

ANID/FONDECYT

Agradecimentos

To ANID/FONDECYT Regular project N° 1201375 and iniciacion project N° 11201107