Development of Nutrient-Rich Media Through Cyanobacterial Amendment and Their Characterization

Abstract

Exogenous addition of growth stimulants or other chemicals to soil-less medium is a common practice for enhancing biomass and productivity, and a promising amendment option can be cyanobacteria, a ubiquitous group of photosynthetic, plant growth promoting and agriculturally beneficial microorganisms, used as biofertilizers in agriculture. The performance of three nitrogen-fixing cyanobacterial cultures- Anabaena torulosa (BF1), Anabaena doliolum (BF4) and Anabaena laxa (RPAN8), through amendment to two media - namely rooting mix (cocopeat, vermiculite and perlite in 3:1:1) and sand contained in Pro-Trays was evaluated at fortnightly intervals up to 30 days. An enhancement, up to 2- to 3-fold in chlorophyll (as an index of photosynthetic biomass) and 30–45% IAA was observed in the extracts of cyanobacterium–amended media, over control; rooting mix was more promising as compared to sand. The addition of cyanobacteria also brought a significant enhancement of 30–40% in the availability of nitrogen and micronutrients–Mn, Cu, Zn and Fe in both media. Phytotoxicity studies with seeds of mustard, radish, maize and wheat, revealed no inhibition, highlighting the promise of these fortified rooting mixes as organic inputs in nursery propagation.