By Dr. Jolly Kabirizi

Lablab purpureus, commonly known as lablab bean, is a twining legume native to tropical and subtropical areas of Africa. It is a deep-rooted, drought-tolerant and annual to short-lived perennial. 

Highworth and Rongai are the major varieties of lablab grown in Uganda. Highworth has purple flowers and black seeds. It produces little herbage that is fibrous. Rongai has white flowers and white and brown seeds. Rongai originates from Rongai in Kenya. It produces a lot of highly palatable herbage; therefore, it has a high level of adoption as a fodder crop in Uganda.

Uses of lablab

Lablab as a food crop

In East and Central Africa, as well as parts of Asia, lablab is mostly used as a pulse crop and both the green pods and mature seeds can be consumed by humans. Lablab beans are edible if boiled well with several changes of the water. Otherwise, they are toxic due to the presence of cyanogenic glycosides that are converted to hydrogen cyanide when consumed. Signs of poisoning include weakness, vomiting, dyspnea, twitching and convulsions. The leaves are eaten raw or cooked like spinach. Young and tender leaves can be harvested, dried, milled and the powder mixed in groundnut sauce. The flowers can be eaten raw or steamed. The root can be boiled or baked for food.

Lablab purpureus cultivar Highworth

As a forage crop

Lablab leaves are a very good source of protein for cattle, goats, sheep, rabbits, pigs and poultry. 

Lablab is a very good pasture legume for cut and carry dairy cattle production system. Lablab hay or silage improves digestibility of poor-quality roughages such as grass hay and cereal stover normally fed to animals in the dry season. A mixture of sweet potato vines or napier grass and lablab silage improves the live weight gain of cattle by 25 %. At a low-performance level, lablab silage can account for 30 percent of the diet, reducing feed purchasing costs.

Processed (roasted and milled) dry lablab beans can be included up to 5% level in broiler starter and up to 10% level in broiler finisher diets without any adverse effect on the performance of the birds. It is possible to include processed lablab seeds in layer diets up to 100 and 150 g/kg in situations of acute scarcity and/or high cost of grain and concentrates. Supplementing layers with fresh lablab leaves results in slightly heavier and yellow yolk colour.

Lablab with its ability to out-yield conventional forage crops, especially during the dry season, and its enhanced nutritive value, is a fodder crop of great significance for livestock.

Cover crop/green manure

Lablab is used as nitrogen-fixing green manure to improve soil quality. It produces more dry matter than cowpea, especially during drought. It not only produces nitrogen through fixation but returns nitrogen through leaf decay. 

Lablab can be used as a cover crop. Its dense green cover during the dry season protects the soil against the action of the sun's rays and decreases erosion by wind or rain. As green manure, it provides organic matter, minerals and fixes nitrogen into the soil thereby improving crop yields in an economic and environmentally friendly manner. Lablab has an extensive root system that improves the physical condition and function of the soil. Lablab can be planted in a banana plantation to improve soil fertility and control weeds but it must be managed well because lablab plants can have a smothering effect on the banana plants thereby reducing banana yield.

Source of income

The demand for pasture seed, hay and silage for development of livestock feed resources is increasing rapidly in Uganda. Producing lablab seeds, hay or silage is a good investment for farmers and youth. Lablab seed costs sh25,000 to 35,000. Lablab hay costs sh500 per kg. Average lablab seed yield per acre per year is 800-1,200 kgs. Depending on the variety, climate, soil fertility and management of the crop.

In our next article, we will tell you on how to grow Lablab