In this paper, the impact of Pontoscolex corethrurus on Acacia mangium growth and its phytoremediation efficiency in metal-contaminated soils were studied in a greenhouse pot culture under four treatments: non contaminated soil-non inoculated, control (C); non contaminated soilinoculated (NcI); contaminated soil-non inoculated (CNi); contaminated soil-inoculated (CI). The results showed that A. mangium growth performance and its Pb, Ni and Cr uptake were significantly (P<0.05) increased under CI treatment. Under CNi treatment, A. mangium uptake more Ni and Cr content in root tissue than in shoot tissue. But for Pb, the greater content was noted in shoot tissue. A. mangium noninoculated preferentially promoted the phytoimmobilization process for Cr and Ni and the phytoextraction process for Pb. However, under CI treatment, the greater content of potential toxic elements (Cr, Ni and Pb) was observed in roots tissue and A. mangium inoculated promoted the phytoimmobilization process for Cr, Ni and Pb. In addition, the phytoextraction efficiency (PEE) of A. mangium increase (ranged 0.1% under CNi to 14% under CI treatment. This study indicates that earthworms can be used to enhance the phytoremediation efficiency of metal-tolerant plant species in contaminated soil.

To generate needed information for fertility of the University's agro-pastoral farm on a large scale, three representative soil profile pits (P1, P2 and P3) were carried out, and two fixed soil layers depths (0-20, 20-40 cm) were taken (three replicates). 18 composite soil samples were airdried and passed through a 2-mm sieve prior laboratory analysis. Eutric Ferralsol-P1 (14.41 ha), Eutric Cambisol-P2 (6.53 ha) and Dystric Gleysol-P3 (8.82 ha) were found using CPCS and FAO's Guidelines for Soil. Soil reaction was strongly too slightly acid (5.0 to 6.5). Total nitrogen (TN), organic carbon (OC) and available phosphorus (Av. P) decreased with depth. OC, though being low (0.5 to 1 g.kg -1 ), whereas Tot.N was medium (0.06 to 0.16 g.kg -1 ), and, Av. P was rated as medium to high (21.0 to 47.33 mg.kg -1 ). Cation exchange capacity ranged from medium (5.12 -6.68 cmol.kg -1 ) to high (15.1 -18.2 cmol.kg -1 ). On the basis of silt/clay ratios, degree of weathering decreased from Dystric Gleysol-P3 > Eutric Ferralsol-P1 > Eutric Cambisol-P2. The soils were rated as having medium fertility and P3 was regarded as generally good agro-productive characteristics for savannah agriculture. Specific land management and cropping systems were recommended for sustainable utilization of soils.

Despite its status as the first world's cocoa producer, the cocoa production system in Côte d'Ivoire remains characterized by low yields. To solve this problem, a study was carried out on the cocoa farms of the Agricultural Society of Bandama, in southern center of Côte d'Ivoire, in the forest and savannah transition zone. It focused on determining the impact of associated forest species in cocoa farms on cocoa tree development. Thus, the associated tree species have been inventoried. The number of associated species per hectare allowed classification of the cocoa farm according to the degree of shade. From o to more than 80 trees / ha, rates of parasitic attack and mortality increase, while yield of cocoa bean decreases. For cocoa trees at the beginning of maximum yield stage (8 years old plantation), the full-sun system is more productive, with 498 kg of cocoa beans / ha. For the highest density of associated forestspecies, the yield was 127 kg / ha, with a cocoa plant success rate of 55% and a parasitic attack rate of 40%. Moreover, the parasitic attack rate of less than 20%, due to the associated trees, could lead to a reduction of almost half of the potential yield. To avoid a fall in yield and maintain the success rate at an acceptable level, in shade systems, a threshold ISSN 1857-7431 165 of 25 to 30 associated trees / ha has been established. But the parasitic attacks, responsible for the drop in yield should be controlled.European Scientific Journal January 2017 edition Vol.13, No.1 ISSN: 1857 -7881 (Print) e -Keywords: Cocoa production, density of associated forestspecies, parasitic attack, yield, Côte d 'Ivoire RésuméMalgré son rang de premier producteur mondial de cacao, la cacaoculture ivoirienne demeure caractérisée par de faibles rendements. Pour résoudre ce problème, une étude a été menée dans les parcelles de la Société Agricole du Bandama, au centre sud de la Côte d'Ivoire, en zone de transition forêt savane. Elle a porté sur la détermination de l'impact des arbres forestiers associés aux exploitations, sur le développement des cacaoyers de 8 ans (stade d'amorce de rendement maximum). Ainsi, l'inventaire de ces espèces et leur densité ont-ils permis de classifier les parcelles selon le degré d'ombrage. De o à plus de 80 arbres/ha, les taux d'attaques parasitaires et de mortalité augmentent, alors que le rendement en fève de cacao décroit. Dans les conditions de cette étude, le système sous plein soleil a été plus productif, avec 498 kg de fèves/ha, contre 127 kg/ha pour les plus fortes densités d'arbres associés, avec des taux moyens de 55 % de réussite et 40 % d'attaques parasitaire. Pour éviter la chute du rendement et maintenir le taux de réussite à un niveau acceptable, dans les systèmes sous ombrage, un seuil de 25 à 30 arbres associés/ha a été établi. Mais les attaques parasitaires, responsables de la chute du rendement, devraient être contrôlées.

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En Côte d’Ivoire, la pratique des cultures continues ont entrainé la pauvreté des sols en éléments nutritifs. Pour y remédier, des espèces biofertilisantes en occurrence des légumineuses subligneuses susceptibles d’influer sur la disponibilité des éléments nutritifs du sol sont plantées dans les jachères pour la restauration de la fertilité. Cette étude sur le recensement et les caractérisations physicochimiques du sol et des légumineuses utilisées comme biofertilisants dans les jachères a été conduite à Daloa. La caractérisation chimique de ces végétaux réalisée sur la biomasse racinaire fraîche séchée au four à 65 ° C pendant 72 heures puis broyée et tamisée à une taille de 0,5 mm, a porté sur les compositions totales en N, P, K, Ca, Mg, C. Quant à la caractérisation du sol prélevé à 0-20 cm de profondeur, le pH, la taille des particules, l'azote total, le carbone organique, la capacité d'échange de cations, le P disponible et le K ont été analysés. Les prospections réalisées dans ces jachères ont permis de recenser six légumineuses comme culture principale. Ces légumineuses sont majoritairement lianescentes (50 %) contre 33 % des herbacées et 17 % d’arbustes. Les caractéristiques chimiques des racines ont montré une différence de variation de l’azote du témoin (13 g kg-1) à Mimosa invisa (28 g kg-1). Les concentrations en N, P, K ont été maximales chez toutes les espèces à l’exception de Mimosa invisa et Crotalaria retusa. Cependant, chez Mimosa invisa , les fortes concentrations de CEC (13,8 cmolc kg-1) et de C (27 g kg-1) ont été enregistrées. Les concentrations de phosphores (3,9 g kg-1) et de potassiums (53 g kg-1 de K) sont maximales respectivement chez Crotalaria goreensis et Crotalaria retusa. L’usage de ces légumineuses semble indispensable à la reconstitution de l’horizon humifère donc susceptible de restaurer la fertilité du sol et d’influencer la croissance des cultures non fixatrice d’azote. Akedrin et al., 2020 Journal of Animal & Plant Sciences (J.Anim.Plant Sci. ISSN 2071-7024) Vol.45 (1): 7771-7782 https://doi.org/10.35759/JAnmPlSci.v45-1.2 7772 Monograph of subligneous legumes used for the biofertilization of improved fallow soils in Daloa (Côte d'Ivoire). ABSTRACT In Côte d'Ivoire, the practice of continuous cultivation has resulted in poor nutrient soils. To remedy this, biofertilizing species in the form of subligneous legumes likely to influence the availability of soil nutrients are planted in fallows to restore fertility. This study on the inventory and the physico-chemical characterization of the legume species used as biofertilizers in fallows was conducted in Daloa. The chemical characterization of these plants was carried out from fresh root biomass dried in an oven at 65 ° C for 72 hours then crushed and sieved to a size of 0.5 mm. The analyses related to the total compositions in N, P, K, Ca, Mg, and C. As for the characterization of the soil sampled at 0-20 cm depth, the pH, the size of the particles, Total nitrogen, the organic carbon, cation exchange capacity, available P and K were analyzed. Surveys carried out in these fallows have identified six legumes as the main crop. These legumes are mostly creeping (50%) compared to herbaceous (33%) and shrubs (17%). The chemical characteristics of the roots showed a difference in the variation of nitrogen from the control (13 g kg-1) to Mimosa invisa (28 g kg-1). Concentrations of N, P, and K were highest in all species except Mimosa invisa and Crotalaria retusa. However, in Mimosa invisa, high concentrations of CEC (13.8 cmolc kg-1) and C (27 g kg-1) were recorded. Similarly, the concentrations of phosphorus (3.9 g kg-1) and potassium (53 g kg-1 K) are maximum in Crotalaria goreensis and Crotalaria retusa respectively. The use of these legumes seems essential to the reconstruction of the humiferous horizon, therefore likely to restore soil fertility and influence the growth of crops that do not fix nitrogen.