Farmers find benefits in a dreaded invasive weed

In a project based on the principle that if you can’t stop it, harness it, pastoralists in the arid Baringo district have found a way to commercialise a foreign weed that has for more than 20 years invaded their land and killed their livestock.Prosopis juliflora, known as Mathenge, thrives in harsh climates and spreads rapidly in arid and semi-arid areas,covering huge tracts of land and wiping out other species along the way.

It was introduced into Baringo, Tana River, Turkana districts and other arid and semi arid areas due to its extensive root system which was intended to reverse soil erosion and deforestation.

However, the galloping weed disfigures the jaws of livestock that feed on it due to its hard pods and causes tooth decay because of the pods’ high sugar content. In serious circumstances animals have lost their tongues and even died after feeding on the weed. Its poisonous thorns also regularly cause inflammation to both humans and livestock, which takes weeks to subside, and in some cases, where infection persists untreated, has led to amputation of limbs.

However, with the help of scientists, farmers have now managed to harvest the pods and grind them into a powder to make high energy feed-blocks for livestock that can provide a supplementary feed source, rich in carbohydrate and protein, for when other grazing is limited.

Communities in the area are now mobilising on a large scale to collect and process the pods and market them. Already feed manufacturers have expressed interest in buying the product, including Unga Feeds, Tosha Feeds, Sigma Feeds and Pwani Millers.

Farmers use a machine called a hammer mill to grind the pods after they have been dried. The powder is then put in another machine that makes the final blocks.
“These pods, if you have a taste of one, you will find that it has a lot of sugar in it. The outer cover and much of it has a lot of sugar and there is also a lot of fibre in it. So there are carbohydrates, the sugar and the seed, which is actually very rich in proteins.

But the trick is that when the pod is eaten whole, the protein in the seed is not utilised because it goes through the alimentary canal without being assimilated in the body,” said Patrick Mutua, an assistant Livestock Production officer who is involved in this project. The blocks, which are high in energy, are mixed with other feeds.

This domestication of the weed is one of many ways scientists are now advocating the effective management of the invasive weed. Eradication of the plant has proven to be very difficult or sometimes impossible, as the seeds can stay dormant for as long as 10 years but germinate very aggressively once conditions are conducive.  Scientists have proposed harnessing the tree for different uses, while using techniques such as pruning and thinning of single trees.

Bee-keepers planting Mathenge’ near hives, have also benefited as its flowers are an important source of nectar and pollen for high quality honey.
A survey done by the Kenya Forestry Research Institute (KEFRI) and the Department of Forestry in 2007 showed that ‘Mathenge’ tree products could earn farmers in arid and semi-arid areas Sh155,000 per household every year if well marketed.

The first documented introductions of Prosopis juliflora to Kenya was in 1973 for the rehabilitation of quarries near the coastal city of Mombasa, with seed sourced from Brazil and Hawaii.

Written by Bob Koigi

• < Prev
• Next >