The fibrous component might be useful as a base for a biogas-producing system. Methane-producing bacteria require such nutrients as nitrogen, potassium, and phosphorus. Many studies have shown that the water hyacinth provides these elements in the quantity and proportion adequate for good growth of bacteria and for satisfactory gas production.
Work at NASA has demonstrated that each 2.2 lbs. of water hyacinth (dry weight) yields about 83 gallons of biogas, with an average methane content of 69 per cent. As an animal feed, it has been used fresh. In experiments with pigs in fresh water hyacinth was substituted for 20 per cent of commercial feed without toxicological problems or effects on rate of growth.
At present, an attempt is being made to introduce the leaf and/or aerial part with flowers as a source of pigments in the diets of laying hens.
Silage composed of water hyacinth can be used for ruminant diets (Any of various hoofed, even-toed, usually horned mammals, such as cattle, sheep, goats, deer, and giraffes, characteristically having a stomach divided into four compartments and chewing a cud consisting of regurgitated, partially digested food) with excellent results for acceptability, dry matter, and protein digestibility. Water hyacinths have a water content of over 90 per cent. The dry matter contains between 10 and 26 per cent of crude protein, but the leaves contain higher levels (about 38 per cent). The mineral content depends directly on the water where the hyacinth grows, but the mean value ranges from 17.0 to 26 per cent.
The fiber level averages about 20 per cent. Biological evaluation of flour made from the whole plant or any of its parts fed to rats gave good results. For leaf flour, for example, a net protein ratio (NPR) value of 3.7 was found; for petioles, the NPR was 1.7, but was expected because of the high fiber content in this part of the plant. For the total plant, the result was poor, but this can be explained on the basis of its high fiber content, and principally because of the high mineral levels in the roots.
Michael Burton Sr.
AAAA Hyacinth Harvesting