Monday, March 28, 2011

Communicating weed management strategies

AfricaRice scientists and their national partners are collaborating to find socially and economically acceptable and effective weed management options for inland valleys, which have high potential of rice production in West Africa.

They are studying farmers’ knowledge of weed problems and mitigation methods. Using participatory approaches they are also optimizing crop establishment methods with respect to weed suppression and input levels.

Though the scientific results of this work have yet to be analyzed, a direct result of the interventions can already be noted in Bende village in Umuahia region of eastern
Nigeria. Here rice farmers have already adopted the practice of line transplanting. This was suggested by AfricaRice to facilitate weed management operations and to reduce weed pressure due to higher planting densities.

An important component of the integrated weed management approach is the use of herbicides. In the past years, the proper use of herbicides, including selection of effective products and application times, was studied as part of an integrated crop management strategy.

This has resulted in a set of practical and effective recommendations which are currently being followed by thousands of farmers in the irrigated production schemes in the Sahel.
AfricaRice is training farmers on appropriate herbicide use through the development of modules as part of participatory learning and action research (PLAR).

Thousands of rice farmers in eight countries in West Africa and two in East Africa, have been exposed to this farmer-participatory approach. More recently these modules have been converted into radio scripts and learning videos that should encourage farmers to improve their weed management strategy.

Establishing communication linkages with farmers is a must when dealing with weeds. It is necessary to know which weeds are emerging, and also to gain insights into farmers’ understanding of the problems as well as local management strategies. AfricaRice has been discussing with farmers through field-level meetings, and through PLAR activities.

Rice farmers in inland valleys in Benin, Nigeria, Côte d’Ivoire and Burkina Faso have been interviewed on their knowledge on weed biology and control. This information is currently being analyzed and will be used to set priorities and fine-tune future research endeavors.

There are also times when farmers find value for weeds. Many of the wild plant species found in rice fields also have their usefulness. A study by AfricaRice and Wageningen University found that farmers in Benin and Togo distinguish between undisputable weeds and plants which have some value. Farmers let the useful plants stay during hand weeding.

While developing acceptable weed management strategies, AfricaRice intends to address this dual role of wild plants in farmers’ fields.

Further reading :

Rodenburg J, Meinke H, Johnson, DE, 2010. Challenges for weed management in African rice systems in a changing climate. The Journal of Agricultural Science, in press (doi:10.1017/S0021859611000207).

Rodenburg J, Riches CR, Kayeke JM, 2010. Addressing current and future problems of parasitic weeds in rice. Crop Protection 29, 210-221.

Rodenburg J, Johnson DE, 2009. Weed management in rice-based cropping systems in Africa. Advances in Agronomy, 103, 149-218.

Please contact Dr J. Rodenburg, Weed Scientist at AfricaRice, for reprints and further information.

Also visit :

Participatory Learning and Action Research (PLAR) for Integrated Rice Management (IRM) in Inland Valleys of Sub-Saharan Africa: Technical Manual ;
Afroweeds website :
AfroWeedsBook :
Rice Videos :
Rural Radio : Rice farmers use an integrated approach for success in weed management