Effect of drought and haze on the performance of oil palm

One of the most important events occurring during 1997, which affected oil palm cultivation, is related to the "El Nino" phenomenon. This climatic incident resulted in a dramatic drought in many parts of South East Asia. Subsequently uncontrolled development of fires in Indonesia led to the development of haze which spread across neighbouring countries of the region. The first part of the paper presents a tentative estimate of the impact of the drought on future yields (1998 and 1999) of the palms, based on several studies made in the recent past in West Africa and Indonesia. These studies used statistical models about the relationship between the water deficit calculated on a determined period, and the subsequent production of the palms. Seasonal variations are considered, in relation with periods of particular susceptibility of inflorescences during their development. It appears that the age of the palms is also an important factor to take into consideration. The second part of the study deals with the impact of the haze on the performance of oil palms. An estimate of the negative effect on yield is proposed, using an agro-climatic model set up by CIRAD's physiologists. A major short-term impact of the haze was the significant negative effect on oil extraction rate (OER) observed at factories. A statistical model of OER variations according to global radiation is presented and discussed. Although drought and haze occurred during the same period, a tentative split of the corresponding effects has been made. (Résumé d'auteur