Prospecting cyanobacterial formulations as plant-growth-promoting agents for maize hybrids

Abstract

Cyanobacteria represent environment-friendly inputs that can lead to savings of nitrogenous fertilisers, in addition to improving plant growth and soil fertility. The present investigation aimed to evaluate the potential of cyanobacteria inoculants as nutrient-management and plant-growth-promoting options for maize hybrids, which require high inputs of fertilisers. Four types of inoculants comprising consortia of cyanobacteria or cyanobacterium–bacterium and biofilmed preparations using Anabaena were evaluated for 11 maize hybrids. The microbial inoculants performed significantly better than the uninoculated control by bringing about 10–15% enhancement in Soil Plant Analysis Development (SPAD) value, plant height and available nitrogen (N) in the soil, which also led to a saving of 40 kg N ha⁻¹. An additional enrichment of 40–50 kg N ha⁻¹ in the soil was recorded in the treatments A1 (Anabaena–Providencia formulation) and A3 (Anabaena–Trichoderma biofilmed formulation). The cyanobacterial formulations A4 (Anabaena–Azotobacter biofilmed formulation) and A3 in conjunction with B10 (PMH-1), B8 (Bio-9681) and B9 (HM-8) proved to be superior associations. This is the first report on identification of promising cyanobacteria–maize genotype combinations as plant-growth-promoting and N-saving options. These results emphasise the significance of including cyanobacteria formulations in integrated nutrient management practices for this fertiliser-intensive crop.

Keywords: biofertilisers, biofilms, cyanobacteria, maize, nutrient sequestration