Eichhornia crassipes

Water hyacinth, million dollar weed

A free-floating water plant whose leaves are above the water surface. A most troublesome weed as it multiplies rapidly; clogging lakes, rivers and ponds and seriously obstructing traffic on waterways. Extremely difficult to eradicate much research has been devoted to its use in animal feeding; the plant has been the subject of an FAO study (ref. 153).

Being a floating plant it is easily harvested with nets. The fresh plant contains prickly crystals which make it unpalatable. The fresh leaves are sometimes eaten when other feeds are scarce, but normally more than 25% fresh water hyacinth in the feed reduces intake. Furthermore, the high water content of the plant imposes a limitation on the amount of dry matter an animal is capable of ingesting, and the danger of spreading the weed through seeds in the faeces is great. Usually 2:4-D is used to control the plant. The feeding of sprayed plants should be avoided. Although 2:4-d is not toxic to livestock, sprayed plants may accumulate lethal doses of nitrates.

Boiled water hyacinth is used in Southeast Asia as a feed for pigs. The plants are chopped and sometimes mixed with other vegetable wastes, such as banana stems, and boiled slowly for a few hours until the ingredients turn into a paste, to which oil cake, rice bran and sometimes maize and salt are added. The cooked mixture is good for only three days, after which it turns sour. A common formula is 40 kg of water hyacinth, 15 kg of rice bran, 2.5 kg of fish meal and 5 kg of coconut meal. The physical structure of the plant makes it unsuitable for the normal methods of making hay and silage. The plants dry rather quickly in the sun, but the neck between the petiole and the lamina is very brittle. The lamina shrinks and breaks off with handling, leaving only the petiole which remains round and full of air. The hay is therefore very bulky, and it is not palatable to cattle unless mixed with at least 20% molasses. Urea may be included to increase the content of crude protein. The nutritive value per unit of dry natter is too low to warrant the cost of artificial drying.

Because of the high moisture content of water hyacinth it should be wilted in the shade for forty-eight hours and lacerated before ensiling. Molasses should be added, and sodium chloride and urea are reported to increase the nutritive value and quality of the silage. It has also been ensiled with rice straw (4:1 water hyacinth to rice straw) with good results. These silages have been accepted when gradually included in the ration.

The plant juice has also been used for the production of leaf protein concentrate and as a substrate for yeast production.

					As % of dry matter
				DM	CP	CF	Ash	EE	NFE	Ca	P	Ref
Fresh, green part,
India				5.9	13.1	18.2	15.3	1.3	52.1	2.16	0.41	436
Fresh, green part,
Philippines				7.8	12.8	24.6	11.9	3.3	47.4			299
Hay, India					11.6	24.2	17.8	0.7	45.7	2.19	0.64	357
Silage, Philippines				10.1	9.9	19.7	19.0	1.5	49.9			299
Haylage, India				33.5	11.4	24.5	20.1	1.4	42.6	2.02	0.23	357
Haylage with 2%
salt, India				46.8	13.9	17.4	18.9	1.5	48.3	1.70	0.21	"
Dried root, Sudan				92.7	5.8	20.5	3.7	0.9	69.1			93
							Digestibility (%)
					Animal		CP	CF	EE	NFE	ME	Ref
Hay					Zebu		37.9	62.1	53.4	60.4	1.76	357
Silage					Sheep		56.1	57.1	76.2	78.5	2.15	299