Columnists

Kenya must start tighter monitoring of farm herbicides

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A fruit and vegetables market in Nyeri. FILE PHOTO | NMG

It is common for farmers in developing countries to use herbicides as a weed control measure.

The Glyphosate herbicide is particularly heavily used because it requires less field preparation and fewer expenses linked to farm machinery. In 2011, approximately 650,000 tonnes of glyphosate products were used worldwide and this figure is projected to double by 2017.

In Kenya, although there is no public data on the amount of glyphosate use, there are 28 different glyphosate-based products registered. The products are mostly applied within tea and coffee plantations as well as in beans, sugarcane, barley, baby corn and maize.

Despite the seeming economic and ecological benefits such as soil erosion prevention, organic matter loss, water evaporation and biodiversity, there is a need to question the adverse effects of extensive application of large quantities of these herbicides on human health and the environment.

In Europe, there has been heated debates between scientists, NGOs, government and industry over the past two years on the re-registration of this active ingredient.

Some argue that glyphosate is likely to cause cancer and should therefore not be re-registered, an argument that has been supported by the International Agency for Research on Cancer.

Others argue that any carcinogenic properties have not been proven conclusively and that glyphosate should thus be re-registered. The result of this discussion is unfortunately that glyphosate was on November 27, 2017 reregistered for the next five years.

In Kenya, as in many other countries, there are no discussions and no proper regulation in place.

Many farmers generally perceive the use of herbicides and other pesticides not as problematic — a perception that is mainly attributed to lack of training and awareness.

Monitoring programmes in Europe and the US show ecotoxicologically relevant glyphosate concentrations in water, urine and food (example, beer and bread), so one can expect elevated concentrations in developing countries as well.

There is no environmental monitoring programme in the country to gather information on glyphosate pollution in water, soil and air nor is there glyphosate residue monitoring in food.

Interestingly, this is not only the case for glyphosate but for all pesticides being used in this country. A paper by Rockström et al in 2009 stated that one of the biggest environmental problems is pollution, since we do not know its extent globally.

This argument was reemphasised at the just concluded United Nations Environment Assembly in Nairobi.

We should not wait until this product is forbidden or restricted but rather act now.

Integrated or organic weed management includes strategies like covering bare soil with mulch (oganic, green like dry grass and maize stalk residues); cover cropping with legumes, which then fix nitrogen from the air and help improve soil fertility.

Other possible solutions include intercropping with nitrogen fixers like caliandra, lucern, pigeon peas, agroforestry. It is certainly worth trying and implementing.

Silke Bollmohr is Environmental scientist and managing director of EcoTrac Consulting.