Mathenge weed invades grazing fields in Turkana county

Proposis juliflora (Mathenge) vegetation at Marigat, Baringo County on June 23, 2017. [Caroline Chebet, Standard]

Mathenge weed (Prosopis juliflora) has invaded grazing fields and farms in Turkana County.

The weed that is spreading at an alarming rate has extended into Lake Turkana and sections of rivers, blocking the flow of water to irrigation schemes.

Residents of flood-prone Napetet sub-location on the outskirts of Lodwar town have now resorted to clearing dense thickets of the thorny weed, which encourages siltation of Kawalase river, forcing it to direct water to their homes whenever it floods.

"Frequent destructive flooding of the 100-metre wide river was contributed to by the thicket and heavy siltation that blocked the original water channel. Our homes are always submerged whenever the river swells," said Esther Korima.

Governor Josphat Nanok said large tracts of arable land at Lotikipi Basin have a large concentration of Mathenge shrubs. He has appealed to the Ministry of Environment and Forestry to work with his administration to stem the spread of the shrub.

"More needs to be done to combat prosopis invasion in Lotikipi aquifer, shores of Lake Turkana, and Turkwel and Kerio riverine," said Nanok.

Jesse Owino, a research scientist at Kenya Forestry Research Institute, said the weed was introduced in the county in the 1980s and early 1990s to address desertification in drought-prone regions like Turkana and Baringo counties by increasing forest cover but "its invasive nature is currently a nightmare to locals".

"In some areas, the plant has forced residents to migrate from their ancestral homes after it depleted the sub-soil water, making the land not viable for agriculture," Dr Owino said.

He proposed support for environmental groups in the county to turn Mathenge trees into a source of income through charcoal burning.

Charles Ekidor, a pastoralist, said the thorn of green Mathenge is poisonous as it can disfigure the part of the body that it pricks.

"The seed pods are harmful to livestock. When consumed in large quantities, they interfere with the digestive system and that can be fatal," said Ekidor.