Estimated values for selected water hyacinth by-products

Abstract

By-products which can be made from water hyacinths as suggested by the literature were considered and attempts were made to measure the demand for selected by-products—compost, soil amendment, and feed ingredient in beef cattle diets. Using data from a firm in Florida, an upper limit on the value of water hyacinths was determined to be $6.42 per wet ton when used in a compost blend. There was no basis for determining if the actual value was near this bound or how many hyacinths would be demanded at this price. However, one would suspect that only a very limited quantity could be used in this way. An estimate of the value of water hyacinth as a soil amendment was made. It is doubtful that the value as a soil amendment would cover the costs of transporting and spreading hyacinths on the land. Chopped and ensiled water hyacinths were treated as different feed ingredients for cows weighing 400 kilograms and nursing calves and for finishing steer calves weighing 300 kilograms. A least-cost diet model was used to determine a value for water hyacinths in these diets. The diets were run for three time periods to show how the demand for water hyacinths as a feed ingredient has changed in the last two years as other feed prices have increased. The results agree with theoretical expectations that there has been an increased potential demand for water hyacinths as a feed ingredient due to the increased prices of other feed ingredients. But even with the increased potential demand for water hyacinths the quantity demanded is not very significant. For example, if all the cattle in Florida were fed year around with a diet including water hyacinths at the highest rate estimated in the least-cost diets, then all of the demand could be taken care of by a small percentage (less than 3) of the total infested area in the state in any month during the growing season.