The Invasion of Chromolaena odorata (L.) King & Robinson (ex Eupatorium odoratum), and Competition with the Native Flora, in a Rain Forest Zone, South-West Cote d'Ivoire

1991 ◽  
Vol 18 (1) ◽  
pp. 13 ◽  
Author(s):  
Anneke de Rouw
2020 ◽  
Vol 5 (6) ◽  
pp. 1659-1667
Author(s):  
Franck Zokou Oro ◽  
Hermann-Desiré Lallie ◽  
Nahoua Koné ◽  
Juslin Kouadio ◽  
Hortense Atta Diallo

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252770
Author(s):  
Pascal O. Aigbedion-Atalor ◽  
Itohan Idemudia ◽  
Medetissi Adom ◽  
Ethelyn E. Forchibe ◽  
Hospice Tossou ◽  
...  

The Neotropical invasive plant Chromolaena odorata R.M. King and H. Robinson (Asteraceae) is a serious weed in West and Central Africa and two biological control agents that have been introduced into West Africa to help reduce its impacts on agriculture and biodiversity, have established. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), has spread widely across West Africa since its release in only Côte d’Ivoire, occurring in six countries. This study aimed to investigate whether the gall fly had spread further across West Africa and into Central Africa. Here, we surveyed C. odorata for C. connexa galls in Cameroon between October 2018 and October 2020, along roadsides, on farms, residential areas, and abandoned plots, encompassing various vegetation types. Additional surveys were conducted across four countries (Ghana, Togo, Benin Republic and Nigeria) in West Africa that we considered the probable pathway for the spread of the gall fly into Central Africa. Cecidochares connexa was present at five of the six locations surveyed in Cameroon, albeit in varying abundance. In Africa, these findings represent the first-ever report of C. connexa outside of West Africa. In West Africa, we recorded significant expansion in the geographic range of C. connexa, as reflected in the absent-present record of C. connexa in two locations in Nigeria and one in Ghana, as well as its occurrence in all locations surveyed in Benin Republic and Togo. Clearly, Ghana, Togo, Benin Republic and Nigeria served as the dispersal pathway of C. connexa from the release sites in Côte d’Ivoire into Cameroon, covering over 2,300 km. Following the spread and establishment of C. connexa into Cameroon, we anticipate that it will continue to spread further into other parts of Central Africa which are climatically suitable. Cecidochares connexa is currently the only biological control agent for C. odorata in Central Africa. Given that it has significantly reduced populations of C. odorata in other countries where it has established, it is expected to have a similar impact in Central Africa.


2020 ◽  
Vol 14 (1) ◽  
pp. 289-305
Author(s):  
Edwige-Gwladys Kawojou Gnimassoun ◽  
Jean Baptiste Djétchi Ettien ◽  
Dominique Masse

En Côte d’Ivoire, la pauvreté des sols est une contrainte pour la productivité agricole. L’objectif de cette étude était de produire un compost à base de rafles de palmier afin d’améliorer les propriétés physicochimiques des sols pauvres en matières organiques. Quatre traitements T0 (720 kg de rafles + 0 kg de fientes de volaille), T1 (720 kg de rafles + 200 kg de fientes de volaille), T2 (720 kg de rafles + 400 kg de fientes de volaille) et T3 (720 kg de rafles + 600 kg de fientes de volaille), ont été compostés durant 6 mois. Les teneurs en nutriments et éléments traces métalliques (ETM) dans chacun des traitements ont été évaluées et comparées les unes par rapport aux autres. Le traitement T3 a révélé des teneurs élevées en N (14840 mg.kg-1), P (6327,5 mg.kg-1), K (19930 mg.kg-1), Mg (14160 mg.kg-1) et Ca (4140 mg.kg-1) et des concentrations en ETM en deçà des seuils de toxicité avec Pb : 88,5 mg.kg-1, Zn : 167,5 mg.kg-1et Cr : 58 mg.kg-1). Ce compost pourrait donc être utilisé comme amendement pour ces ferralsols marginaux dans le Sud-Ouest de la Côte d’Ivoire. © 2020 International Formulae Group. All rights reserved. Mots clés: Rafles de palmier, compost, fertilité des sols, ETM, Côte d’Ivoire English Title: Characterization of the physicochemical and chemical properties of a compost issued from a mixture of palm empty fruit bunch and chicken manure in South West of Côte d’Ivoire English Abstract In Côte d’Ivoire, soil poverty reduces agricultural productivity. The aim of this study is to produce compost based on palm stalks to improve the physico-chemical properties of sandy soils with low organic matter content. Four treatments T0 (720 kg of empty fruit bunch + 0 kg of chicken manure), T1 (720 kg of empty fruit bunch + 200 kg of chicken manure), T2 (720 kg of empty fruit bunch + 400 kg of chicken manure) and T3 (720 kg of empty fruit bunch + 600 kg of chicken manure) of mixed various quantities of palm empty fruit bunch and chicken manure were up in field for 6 months. The levels of nutrients and heavy metal contents in each treatment were evaluated and compared against each other. Treatment T3 highlights high levels of N (14840 mg.kg-1), P (6327.5 mg.kg-1), K (19930 mg.kg-1), Mg (14160 mg.kg-1) and Ca (4140 mg.kg-1) and heavy metal content below the toxicity thresholds (Pb: 88.5 mg.kg-1, Zn: 167.5 mg.kg-1 and Cr: 58 mg.kg-1). This compost could therefore be used as sandy soil amendment in the South West of Côte d’Ivoire. © 2020 International Formulae Group. All rights reserved. Keywords: Palm empty fruit bunch, compost, soil fertility, heavy metal, Côte d’Ivoire


Author(s):  
Traore Kassoum

Preserving the forest is a "vital" action for maintaining the climate balance and promoting eco-tourism. The history mentions that the Ivorian forests played an important role in the dynamics of the development of the country because they sheltered a great diversity floristic and wildlife. Unfortunately, from 16 million hectares at the beginning of the last century (1900), the dense rainforest increased to 9 million hectares in 1965 and 3 million hectares in 1991. Today, it is estimated at about 2.5 million hectares. This situation is attributable to extensive agriculture based on the technique of shifting cultivation, the overexploitation of the forest with timber and wood energy and bush fires. Moreover, the phenomenon of forest infiltration with regard to the occupation or colonization of forest areas, particularly in the south-west of the country by migrants to build houses and / or villages, is an important factor in the disappearance of the forest. Also, successive crises that the country has experienced since 1999 until 2010 (post-election), with periods of tension, have led to mass displacements of populations. This regrouping of the populations in turn caused the clearing of the forest areas for their relocation. Thus, from the analysis of the situation of forest pressure in Côte d'Ivoire, the Ministry in charge of the management of the Ivorian forest cover indicates that the accelerated rate of destruction of Ivorian forests has today reached an estimated average of 450,000 hectares a year. The forest situation is catastrophic, if corrective measures are not taken and put into effect, the forest cover is supposed to disappear around 2040. The present work attempts to contribute to the level of reflection undertaken to improve the management of the sector. Résumé: Préserver la forêt est une action « vitale » pour le maintien de l’équilibre climatique et la promotion de l’éco-tourisme. L’histoire mentionne que les forêts ivoiriennes ont joué un rôle important dans la dynamique du développement du pays car elles abritaient une grande diversité floristique et faunique. Malheureusement, de 16 millions d’hectares au début du siècle dernier (année 1900), la forêt dense humide est passée à 9 millions d’hectares en 1965 et à 3 millions d’hectares en 1991. Aujourd’hui, elle est estimée à environ 2,5 millions d’hectares. Cette situation est imputable à l’agriculture extensive basée sur la technique des cultures itinérantes sur brûlis, la surexploitation de la forêt en bois d’œuvre et bois énergie et les feux de brousse. Par ailleurs, le phénomène de l’infiltration des forêts au regard de l’occupation ou la colonisation des zones forestières notamment du Sud-Ouest du pays par des migrants pour bâtir les habitations et/ou des villages est un facteur important de la disparition du couvert forestier.Egalement, les crises successives qu’a connues le pays depuis 1999 jusqu’en 2010 (post-électorale), populations. Ce regroupement des populations à son tour, a occasionné le défrichement des zones forestières pour leur relocalisation. Ainsi, de l’analyse de la situation des pressions sur les forêts en Côte d’Ivoire, le ministère en charge de la gestion du couvert forestier ivoirien indique que le rythme accéléré de destruction des forêts ivoiriennes a atteint de nos jours une moyenne estimée à 450.000 hectares par an. La situation des forêts est catastrophique, si des mesures correctives ne sont pas entreprises et mises en vigueur, le couvert forestier doit en principe disparaitre vers 2040. Le présent travail tente d’apporter sa contribution au niveau des réflexions engagées pour améliorer la gestion du secteur. Mots clés : forêts classées, parcs et réserves, gestion du couvert forestier, Côte d’Ivoire


Acta Tropica ◽  
1997 ◽  
Vol 68 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Traoré Soungalo ◽  
Diarrassouba Soumana ◽  
Sow Moussa ◽  
Riviere François

1996 ◽  
Vol 44 (4) ◽  
pp. 263-277 ◽  
Author(s):  
H. Van Reuler ◽  
B.H. Janssen

In the Tai region of south-west Cote d'Ivoire P is the yield-limiting nutrient on (moderately) well drained soils. In order to find the optimum P application rate, a factorial experiment (2N x 4P x 2K) in three replicates was conducted at two sites during six seasons. The factors investigated were N (0 or 50 kg/ha), P (0, 12.5, 25 or 50 kg P) and K (0 or 50 kg K). N (urea) and K (muriate of potash) applications were split into two equal parts and broadcast. From the third season onwards the N application was raised to 100 kg N. P (triple superphosphate) was placed near the young plants. Upland rice and maize were used as test crops. The experimental sites were located at the crest (Site VII) and lower slope (Site VIII) of a catena. In the first season after clearing at Site VII highest yields were obtained with 12.5 kg P and at Site VIII with an application of 25 kg P. At the latter site also N application increased yields. In an extended cropping period the rice yield level could not be maintained. The efficiency of utilization of absorbed P (EUP) of rice was high in the first season after clearing but decreased in subsequent seasons. This is in contrast to EUP for maize which remained constant with time. Hence, it is concluded that the rice yield decline is caused by other factors than nutrient deficiencies. In all seasons yields were higher at Site VII than at Site VIII. The residual effect of fertilizer-P could reasonably well be described by a simple formula: RFP1 = (0.9 - RFP1)t-1 x RFP1, where RFP and RFP1 are the apparent recovery fractions of fertilizer P in year t and year 1, respectively. In all seasons, except in the first season after clearing, the potential P supply was higher at the crest (Site VII) than at the lower slope (Site VIII). Extending the cropping period proved possible when fertilizers were applied and maize was grown. For both sites fertilizer guidelines could be formulated. Comparison of soil chemical data (pH, organic C, total N and total P) before the start of the experiment and after six seasons did not show changes.


2021 ◽  
Vol 7 (11) ◽  
pp. 320-328
Author(s):  
Kpangui Kouassi Bruno ◽  
Koffi N'Guessan Achille ◽  
Sangne Yao Charles ◽  
Kouakou Kouassi Apollinaire ◽  
Kouassi Jean-Luc ◽  
...  

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