Etude Du Fonctionnement Physiologique D'Un Couvert De Dioscorea Alata Pour Une Utilisation Plus Rationnelle Des Engrais Chimiques

Yam is a very demanding plant in term of soil fertility. Nevertheless in spite of the very large acceptance of this affirmation, little information is available on the real nutriments requirements of yam and how to satisfy them. For instance, numerous mineral fertilization recommendations are provided and the recommended doses are more often important (mainly calculated on the quantity of nutrients exported by harvest). Although there seems to be an increase in yield to fertilizer application, the general picture is confusing. Bibliographic review of the fertilization experiments shows contrasted and more often statistically non-significant responses. Then, it is necessary to conclude that a lot of leachable elements are lost and/or misused by yams. In order to benefit more of the chemical fertilization and to reduce losses by leaching, it is important to better understand the growth and development of yam. In 2004, an experiment was carried out on the effects of mineral fertilization, on the growth and yield of the yam (Dioscorea alata). A "Monteith" type of growth analysis has been implemented : crop cycle, leaf area development, biomass production and distribution and final yield have been studied. Part of the results obtained is presented here under the mineral nutrition point of view.