Biomass Production of Azolla microphylla in Rainwater Solution of Coconut Husk

The present work reports the use of rainwater solution of coconut husk (CCH) as growth media of Azolla microphylla in Thailand. A series of seven experiments were conducted to test the hypothesis that water solution of CCH may be used as growth media of A. microphylla for biomass production. The media treatments of the seven experiments consisted of tap water (TW), rainwater (RW), fertile soil (S), water buffalo manure (M), and CCH depending on experimental conditions. TW and RW were used as media or solvent in the media treatments tested in this study. The fern was grown on the media in 23 L containers under a greenhouse covered with 60% black shade cloth and biomass at least four weeks of growth was evaluated. The results showed that the fern had four to five times greater biomass after four and 12 weeks of growth in the medium RW. The fern had 14‐time greater biomass after four weeks of growth in the media RW solutions of CCH at 10:1–10:9 by volume. Biomass tended to be greater in the media RW solutions of CCH than the medium RW. Biomass was small in the media TW solutions of CCH. To conclude, RW solutions of CCH at 10:1–10:9 by volume can be used as growth media of A. microphylla for biomass production.