Articles

Influences of Historical and Anthropogenic Factors on the Dynamics of Reconstitution of Post-Cultivation Vegetation in the Sub-Sudanese Zone: The Case of the Department of Dianra, North-West Côte D’ivoire

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Prior knowledge of vegetation dynamics, including post-crop recovery dynamics, is necessary for rational and sustainable management of land assets. This study was initiated to assess the influence of historical and anthropogenic factors on post-cultivation reconstitution in the Dianra Department. To this end, information on the history and post-cultivation human activities was collected from farmers. The Phytoecological and dendrometric data were collected using the surface botanical method in the post-cultivation plots. In total, 105 plots of 400 m² were planted in post-cultivation plots between 1 and 32 years old. The influence of historical and anthropogenic factors was assessed using an Analysis of Covariance (ANCOVA), in which the functional traits of the species and the structural attributes of the plots were considered as the variables to be explained and the historical and anthropogenic factors as the explanatory variables. This analysis shows that post-cultivation reconstitution in the sub-Sudanese environment is subject to the influence of several factors, the most perceptible of which are: age, number of years of cultivation, grazed area, cultivation history, groundnut cultivation as the last crop, and cultivation technique by horse and cart. The age, groundnut cultivation as the last crop and the Open Forest/Wooded Savannah cultivation history favoured reconstitution. In contrast, a high number of years of cultivation, grazing and ploughing by horse and cart were unfavourable to reconstitution.

Influence of Rainfall and Water Deficit in the Efficiency of Potassium Fertilizer on the Productivity of Oil Palm (Elaeis Guineensis Jacq.), Grown in Southeastern Côte d’Ivoire

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In Côte d’Ivoire, palm oil occupies a preponderant position in agricultural production, in the economy, as well as consumer fats. Yield remains low, even with improved plant material being popularized whose productivity is estimated at more than 25 tons/ha/year. Trials have been set up in La Mé and Ehania (South-east Côte d’Ivoire), to help improve oil palm productivity, through a comparative study of the efficiency of potassium fertilization applied according to the locality. The experiments were conducted in Fisher blocks, including 5 treatments and 4 repetitions. The treatments included 5 doses of potassium fertilizer (T1, T2, T3, T4, T5) corresponding, respectively, to 1; 1.5; 2; 2.5; 3 kg KCl/tree/year. The results showed that the rainfall recorded in the locality of Ehania was significantly higher than that of La Mé. The average annual rainfall was 2000 mm of water in Ehania against, approximately, 1700 mm of water in La Mé. The yield and its components (weight of the bunch and number of bunches) were gradually improved according to the locality of cultivation by the different doses of fertilizer applied. This improvement was significantly higher on the Ehania plantation compared to that of La Mé. This improvement was approximately 30% and 27% compared to the standard dose of 1 kg KCl/tree/year, respectively, in Ehania and La Mé. It appears that the locality intervenes in the efficiency of potassium fertilizers, in the improvement of yield and its components. Rainfall appears, as, a main factor of productivity observed on the plot of the oil palm. Strict compliance with the choices of suitable areas, combined with reasoned potassium fertilization, will allow a better expression of the production potential of new oil palm plant material, currently being popularized.