Application of seaweed liquid extract improves the growth, yield, and chemical constituents of lemongrass

Abstract

The rapid increase in the adoption of seaweed-based bioproducts in crop production systems can be attributed to their unique bioactive components and significant beneficial effects. In the growing interest of sustainable agricultural practices, the present study aims to reduce the dependency on chemical fertilizers while enhancing crop productivity and quality through seaweed extract. A field experiment was carried out during 2018-2019 and 2019-2020 at CSIR-CIMAP, Allalasandra, Research Center, Bengaluru to study the influence of seaweed liquid extracts as a foliar application on growth, yield, and chemical composition of lemongrass. Results revealed that the growth, herb and essential oil yield of lemongrass was improved significantly by the application of Kappaphycus alvarezii (K sap) at 20% concentration, recording herb and oil yield of 35.86 t ha−1 year−1 and 466.70 kg ha−1 year−1, respectively when conjugated with a recommended dose of fertilizer (RDF), compared to RDF alone, 30.40% and 35.70% in herb and oil yields, respectively, were recorded in this treatment. Notably, the treatment 50% RDF + K sap applied at 7.5% concentration was statistically at par with RDF with respect to the herb as well as oil yield connoting considerable scope of reducing chemical fertilizer requirement for the lemongrass. The functional relationship between herb and oil yield of lemongrass with different concentrations of seaweed sap applied at different crop stages was found to be strongly correlated (r2=0.99 and r2=0.98, respectively). Higher amounts of citronellal (0.70%) Borneol (1.10%), α-Terpineol (1.90%), and Citronellyl acetate (0.4%) were recorded in 20% K sap spray with RDF. The study revealed that the application of marine alga Kappaphycus alvarezii foliar spray above the 10 - 20% concentration significantly increased the herb, essential oil yield, and chemical constituents of lemongrass.