Appui à la production durable d'ignames adaptée à la demande des marchés urbains

Integration of yam in cover crop-based cropping system: constraints and potential

Denis Cornet¹, Philippe Vernier², Firmin Amadji³ and Robert Asiedu⁴

Abstract

Yam is a demanding crop in terms of organic matter and soil fertility, especially the most appreciated and market-valued cultivars (early maturing Dioscorea rotundata) used to prepare the popular dish futu (pounded yam).

Traditionally cultivated in slash and burn cropping systems after a long fallow period in West Africa, yam cultivation is now confronted with a scarcity of fertile soil available for clearing. Hence there is an urgent need to develop improved cropping systems for yam that allow sustainable cultivation and reduce land pressure on the remaining forest area.

Conservation agriculture using direct seeding mulch-based cropping systems is a promising way to develop sustainable agriculture in the tropics. Nevertheless such techniques have been generally grain-oriented (cereals, legumes) and very little has been done on root and tuber crop based systems. This paper presents the results of experiments carried out in the Republic of Benin over 2 years in order to assess the capability and the potential of a direct planting yam cropping system in Pueraria mulch under the conditions of smallholder farms. Three yam types - D. rotundata (1) early and (2) late maturing, and (3) D. alata - were cultivated in three cropping systems: (i) after long duration natural fallow on mounds, as a traditional control; (ii) direct planting in live and (iii) dead Pueraria mulch. Planting in mulch had a positive impact on yield for all yam cultivars, the best results having been achieved with live mulch.

Keywords : yam, cover-crop, Dioscorea, direct planting, Benin

¹ CIRAD Research Unit Genetic Improvement of Vegetatively Propagated Crops, 34398 Montpellier Cedex 5, France; CIRAD-IITA Yam Research Co-ordination Unit, 08BP0932 Cotonou, Republic of Benin; denis.cornet@cirad.fr.

² CIRAD, Research Unit Horticulture, Montpellier, France.

³ INRAB, Centre de Recherche Centre, Save, Republic of Benin.

⁴ International Institute of Tropical Agriculture, Ibadan, Oyo State, Nigeria.

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