Some Interesting Questions About Velvet Beans

Ursula Thomi, working in Chad, asked some interesting questions about the velvet beans she obtained from our seedbank (see ECHO’s book Amaranth to Zai Holes [A-Z] p 169, 289 for more information about velvet beans). We thought the answers would interest others.

QUESTION: The velvet beans we planted do not begin to flower until early October, when it is too dry for the plant to form seeds. Also, intercropping with millet does not work well because the vigorous legume climbs the millet stalks, causing them to bend and making harvesting difficult. Can you suggest a solution?

REPLY: The velvet bean that most workers in the tropics and subtropics use requires short days to bloom. Here in Florida, no matter when this type is planted, the vines begin to bloom around November.

However, in the early 1900’s another type of velvet bean was developed by the U.S. Department of Agriculture and became a major crop in the southeastern part of the United States. The “tropical” velvet bean would never set seed in states other than Florida, because winter would come just about the time the plants would be ready to bloom. Varieties were developed that would produce seed farther north, essentially throughout the “cotton belt.” The beans were grown along with corn for forage and for the nitrogen and organic matter they added to the soil. Farmers used what is called “90-day” or “120-day” velvet bean. Flowering date for this variety seems to depend on how long the plant has been growing and is independent of daylength. Farmers apparently stopped growing them when fertilizers and mechanical corn pickers became common.

ECHO has seldom sent the “90-day” variety to our overseas network because growth appears to be less vigorous and the pods have a bit more itch-producing fuzz than the tropical kind. (The itch problem is still only a fraction of that caused by dreaded wild velvet beans.) Dopamine content appears to by a bit lower in this type than in most selections.

In Chad, the insensitivity to daylength of the “90-day” variety might mean that farmers could produce their own seed before the dry season becomes too severe. Also, because the vigorous growth is a problem, the lesser vigor of the “90-day” variety may be an advantage. Seeds for the “90-day” variety are available from ECHO. Trial packets are free to those working with small farmers overseas; others please send $2.50/packet.

As for intercropping with millet or sorghum, we suggested Thomi try planting the velvet bean a few weeks after these grains, to give the grain a chance to get started before competition begins. In Central America, many farmers actually plant velvet beans near the end of the grain growing season, then let them grow up and cover the harvested grain stalks. We realize this might be too near the dry season to work in her situation.

A 1922 USDA extension bulletin (# 1276), The Velvet Bean, states “The yield of corn is decreased by the beans, depending on the rate and date of planting the beans and soil fertility. When corn is planted several weeks earlier than the beans, little damage occurs as the vines do not make sufficient growth to pull it down before the ears are nearly mature….Even though the yield of corn is decreased, the value of the beans for green manure or feeding will offset the loss to the corn crop. The cost of picking the corn, however, is greater….”

QUESTION: Velvet bean seeds contain dopamine, which can be harmful to animals in large doses. “Do leaves also contain dopamine, or can they be used for animal feeding? Fresh or as hay?”

REPLY: At ECHO, we’ve never seen any reference to whether leaves contain dopamine. However, we would not be surprised if it is found only in the seeds. According to the USDA bulletin quoted above, both leaves and seeds can be used as animal feed within guidelines. It states that large quantities were used for animal feed (in 1922):

“The value of velvet beans as a winter pasture, either for carrying cattle through the winter or for fattening them, is well established…. The crop may also be used for silage and hay,” though “velvet beans are seldom used for hay because of the difficulty in handling the long tangled vines. If hay is to be made it must be harvested before many of the pods mature because the leaves shatter rapidly as the pods approach maturity. The hay is coarse and rough at best and is not relished by horses and mules.”

“The most important use of the velvet bean is as a grazing crop for cattle and hogs in the autumn and winter. …Hogs should be allowed to follow cattle to consume the beans which they have wasted [see later caution on using too much in pig rations]….A good stand of velvet beans should produce about 200 pounds [91 kg] of beef and 100 pounds [45 kg] of pork per acre.”

“As velvet bean [plants and seeds] are very high in digestible protein, great care should be exercised in feeding them to livestock, especially at first. After the animals become accustomed to the beans they should be kept in the field for only a short period each day until the crop is somewhat reduced, as excessive consumption is a waste of concentrated feed. In addition, overfeeding sometimes has a laxative effect.”

The bulletin reports that velvet bean meal was a common feedstuff for some animals, though feeding experiments indicated that “little benefit is derived from grinding the beans for cattle and…winter grazing will probably replace the picking of the beans for grinding.” “In the manufacture of velvet bean meal the beans and pods were crushed together. Because it is not good to feed them alone, a common mixture was to grind velvet beans in the pods with corn in the shuck. "In horse feeds velvet bean meal seldom forms more than 25% of the mixture, whereas for dairy cows it may run as high as 70%. A popular dairy feed is 15% cottonseed meal, 45% corn-and-cob meal and 40% velvet bean meal.”

The protein content of velvet beans is 23%; of pods is 5%; beans and pods ground together 18%. By comparison corn is about 9% protein. “It requires about 2 ½ pounds [1.1 kg] of velvet bean meal [pods and beans] or 1 ½ pounds [0.68 kg] of ground beans to equal the feeding value of 1 pound [0.45 kg] of cottonseed meal.”

Apparently farmers in those days had trouble with spoilage of ground beans. “Ground velvet beans heat quickly, become rancid and mold readily. Whole velvet beans, either dry or soaked, are much more palatable than dry ground velvet beans, which are so unpalatable that steers will not eat enough to make good gains.”

“While [the seeds] usually give good results with cattle and sheep, even when fed in considerable amounts, they are generally unsatisfactory for swine when forming any considerable part of the ration and may even cause severe vomiting and diarrhea. …When velvet beans do not form more than one-fourth of the ration, and an efficient protein supplement…is included, fair results may be obtained.

"At the Florida research station, corn and cracked velvet beans in various proportions were compared with corn alone as feed for pigs. In all cases the pigs made more rapid and cheaper grains on the corn and velvet bean mixture than on corn alone.” In another test shelled corn and soaked velvet bean meal were fed to three hogs, the proportion of velvet bean meal being gradually increased from one-fourth to two-thirds by weight. The hogs made very satisfactory gains, and it was found that the feed produced hard pork.

“Velvet beans cannot be recommended for poultry, based on four years of experiments in North Carolina. When 22½% ground velvet beans was fed in the ratio, it produced a harmful [Ed: unspecified] effect on the health and performance of the birds.” There is little doubt, based on what we now know about the high dopamine content of velvet bean [A-Z page 289 ff], that dopamine was causing the problems with poultry and pigs.

The 1922 bulletin concludes with mention of a human feeding trial. “At the Florida station six persons tested the edibility of velvet bean seed prepared as baked beans. They were found to be very palatable but caused purging and vomiting. The three persons who ate only about half as many of the beans as they would have eaten of baked navy beans were thus affected. The other three, who ate very sparingly, suffered no ill effects. In some sections of the southern states it is reported that when the beans are boiled like peas and the water changed, they make an excellent food and produce no ill effects.”