Dongas assessment: Processes, Management and valorized Opportunities in Karimama District (Northern Benin)

PhD Dissertation:

AVAKOUDJO Julien (2016). Dongas assessment: Processes, Management and valorized Opportunities in Karimama District (Northern Benin). Faculty of Agronomic Sciences. Department of Natural Resources Management, UAC, Benin.

Promotor : Professeur Brice Augustin SINSIN.

 

ABSTRACT: The northern Benin is marked by serious economic and environmental problems due to the « Dongas » and soil erosion, especially in the basins of Alibori and Mekrou in the W National Park and its periphery. The aim of the thesis was to gain a better understanding on the processes and mechanisms of erosion and dongas phenomenon on the one hand, and to identify high value local species in another hand, taking into account their socio-economic and cultural importance in Karimama district in order to develop better rehabilitation strategies of degraded ecosystems.

This work assesses, first of all, the land use dynamics in the W National Park and its periphery throughout diachronic analyses of Landsat images from 1972, 1990 and 2008. Results indicated regressive forest and savanna formations in favor to agricultural lands mainly driven by demography, agriculture and overgrazing. Soil erosion is one of the most recurrent physical degradation of these ecosystems.

The W National Park and its periphery are mostly marked by the dominance of “dongas“. The spatial distribution of this phenomenon was evaluated in Chapter 2 and lead to the dongas inventory and classification. More dongas exist in the Park than in its periphery (i.e. 63.41% versus 36.59%). The dongas settled on six characteristics of ferruginous soils. The most susceptible are the washed and hydromorphic soils with respectively 52.04% and 35.71% of dongas.

The relationships between the mechanisms leading to the dongas formation and development, anthropogenic as well as natural drivers were questionable. Several methods i.e. individual and group interviews, field observations, measurements of soil water infiltration, textural discontinuity as well as the dongas morphological and physico-chemical characteristics were used. Globally, dongas formation results from the interaction of anthropogenic (leading to land cover destruction) and naturals (climat and soil) causes and factors. The dongas development was found to be linked to regressive erosion; the clay load and bulk density increasing in the underlying horizons as a result of textural discontinuity with the collapse of soil in the Park and its periphery. This textural discontinuity is observed at 83.87% of soil profiles.

The assessment of the rainfall from 1970 to 2014 and rainfall erosivity derived from Universal Soil Lost Equation (USLE) and the Modified Fournier Index (MFI) shown seasonal distribution of rainfall during 24 years (53% of individual years) and strong seasonal effect during 19 years (42% of individual years) with increasing values during 45 years period indicating monthly rainfall concentration. Rainfall aggressiveness is high during 7 years (16% of individual years) while 38 years (84% of individual years) have very high aggressiveness. Rainfall erosivity ranged in the medium-strong erosivity and was observed during 39 years (87% of individual years). Monthly rainfall amount is more significantly related to the rainfall erosivity with power regression at Kandi station.

The effect of erosion on physico-chemical soil properties in degraded areas (dongas) in W National Park and its periphery shows that water erosion began with the selective removal of fine soil particles. It significantly affects the bulk density and porosity of the soil. In addition, organic matter (OM) contents in the soil were extremely low. Although the extent of erosion did not significantly affect the OM contents, but it significantly reduces the soil cationic capacity exchange and induces a loss of soil metal cations (especially Ca 2+).

As far as the restoration actions were concerned, local species of high value taking into account their socio-economic and cultural importance were identified. Vitellaria paradoxa, Parkia biglobosa, Borassus aethiopum, Sclerocarya birrea and Tamarindus indica were indicated mostly for land restoration and farmers income improvement while Piliostigma reticulatum was specifically mentioned for soil fertility restoration. Ficus sycomorus, Khaya senegalensis, Balanites aegyptiaca, Afzelia africana and Albizia chevalieri were pointed as pasture. For restoration actions implementation in the Park and its periphery, the growth abilities of five plant species among those proposed by locals (Parkia biglobosa, Moringa oleifera, Khaya senegalensis, Jatropha curcas and Balanithes aegyptiaca) have been tested under two techniques of water and soil conservation (half-moon and Zaï) in dongas. The half-moon was proved to be the best while the Zaï was easily achieved by farmers. Jatropha curcas and Balanites aegyptiaca showed better survival rates and growth in diameter and height at the juvenile stages after fourteen weeks. Their adoption in developing sustainable strategies for the restoration of degraded areas in Northern Benin requires further dry season data.

Keywords: Dongas, erosion, periphery, W National Park, soil and water conservation techniques, Benin.

 

  • FM Deve (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Système Agroforestier à palmier à huile. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Odo Octhèrè (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Bâtiment Professeur Nestor SOKPON (en haut à gauche), bâtiment des volontaires (en bas à gauche), bâtiment Dr KASSA (à droite). (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Bâtiment Professeur Nestor SOKPON (à droite), bâtiment des volontaires de l'UAC (à gauche). (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Mare-Bali (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Vue globale des 5 bâtiments du Laboratoire d’Ecologie Appliquée (LEA). (Photo credit: Dr Akomian Fortuné Azihou / LEA, Octobre 2018)
  • Système agroforestier à Faidherbia albida. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Musée de Zoologie BIOTA et bâtiment Professeur Mama Adamou N'DIAYE. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Brousse tigrée (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Cascade de Tanongou (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Lokoli (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Building of the Laboratory of Applied Ecology (LEA). (Credit photo: Dr Akomian Fortuné Azihou / LEA, Abomey-Calavi, Benin, October 2018)
    Building of the Laboratory of Applied Ecology (LEA). (Credit photo: Dr Akomian Fortuné Azihou / LEA, Abomey-Calavi, Benin, October 2018)
  • Vue globale des bâtiments du Laboratoire d’Ecologie Appliquée (LEA). (Photo credit: Dr Akomian Fortuné Azihou / LEA, Octobre 2018)

Alumni

Names Previous Position at LEA Country Highest Degree as of May 7, 2019
ABOH André PhD Student Benin PhD
ADEBI Yasmina Student Benin BS
ADJOUDEME Rodrigue Research Assistant Benin BS
ADOMOU C. Aristide PhD Student Benin PhD
ADOUNKPÈ Julien PhD Student Benin PhD
AFFEDJOU Guy Research Assistant Benin BS
AGBAHUNGBA Edwige Master Student Benin MS
AGBANI O. Pierre BS Student Benin BS
AGBAZAHOU Honoré Research Assistant Benin
AGBESSI Marcellin Master Student Benin MS
AGBLA Salomon Student Benin BS
AGONYISSA Didier BS Student Benin BS
AGOYI E. Eric Student Benin
AHMADOU Abdoulahi Master Student Niger MS
AHOKPE Elie Research Assistant Benin BS
AHOUANGBENOM Fresnelle Research Assistant Benin BS
AHOUDJI Myrèse PhD Student Benin PhD
AKPONA Adéloui Hugues BS Student Benin BS
AKPONA Tèwogbadé Jean Didier BS Student Benin BS
ALFA GAMBARI IMOROU Safouratou Research Assistant Benin BS
AROUNA Ousséni PhD Student Benin PhD
ASSOGBA DELEKE Amandine PhD Student Benin PhD
ASSOGBA M. Thierry Research Assistant Benin BS
ASSOGBADJO Bidossèssi Eliane Juliette Student Benin BS
ATTIGNON Serge PhD Student Benin PhD
AVAKOUDJO Julien PhD Student Benin PhD
AVOCEVOU-AYISSO Carolle PhD Student Benin PhD
AVODE Auguste Research Assistant Benin BS
AVOHOU Hermane BS Student Benin BS
AZIZOU EL-HADJ Issa PhD Student Benin PhD
BARIMA Sabas Intern Ivory Coast PhD
BASTIN Jean-François Intern Belgium PhD
BONOU Alice Student Benin BS
BONOU N. Wilfried Student Benin BS
CAKPO T. Yvonne Student Benin BS
CHABI Biao Alfred Student Benin BS
Check Abdel Kader Baba Student BS
DADJO Colombe Student Benin BS
DAÏNOU Kasso S. Student Benin BS
DAN Céline B. S. PhD Student Benin PhD
DAOUDA Is-haquou Hugues A. Research Assistant Benin PhD
DELEKE KOKO E.K. Inès PhD Student Benin PhD
DELVAUX Claire PhD Student Belgium PhD
DJAOUGA Mama Student Benin
DJEGO DJOSSOU G. Sylvie PhD Student Benin PhD
DJEGO G. Julien PhD Student Benin PhD
DJENONTIN Jonas PhD Student Benin PhD
DJIBO Boubé Master Student Benin MS
DJODJOUWIN Laurent PhD Student Benin PhD
DJOGBENOU Anyse Student Benin BS
DJOGBENOU  Coovi Paul PhD Student Benin PhD
DJOSSA A. Bruno PhD Student Benin PhD
DONKPEGAN Armel Student Benin
DOSSA S. Justine Student Benin BS
EKUE R.M. Marius PhD Student Benin PhD
FANDOHAN A. Belarmain PhD Student Benin PhD
GANGBE Noël Master Student Benin MS
GAOUE. O. GANDE BS Student Benin PhD
GLELE KAKAÏ A.L. Romain PhD Student Benin PhD
GOUWAKINNOU N. Gerard PhD Student Benin PhD
HAIDARA Mohamed Master Student Mali MS
HOLOU Roland Student for 1) Diploma of Studies in Tropical Agriculture & Controller of Rural Development; and 2) for BS/Ms Agronomy / Agricultural Engineering. USA PhD in Plant, Insect and Microbial Sciences (Option: Plant Biology and Genetics), USA – (Graduated first in his class)
HOUEHOUNHA Rémy PhD Student Benin PhD
HOUESSOU G. Laurent PhD Student Benin PhD
HOUNGBEDJI G. Mariano Student Benin BS
IDOHOU Alix Frank Rodrigue Doctorant Benin PhD
KARIMOUNE Bassirou Master Student Niger MS
KPERA Gnanki Nathalie BS & PhD Student Benin PhD
LOUGBEGNON O. Toussaint PhD Student Benin PhD
MAMADOU Ousmane Master Student Niger MS
MILLER Daniel PhD Student USA PhD
NOBIME Georges PhD Student Benin PhD
NOUROU Yorou PhD Student Benin PhD
SALAKO Valère PhD Student Benin PhD
SALOU Yacouba Master Student Niger MS
SAMBIENI Raoul Stagiaire Benin BS
SANOGO Mamoutou PhD Student Mali PhD
SARE B. Adissatou PhD Student Benin PhD
SINSIN Cocou Aristide Franck PhD Student Benin PhD
TAHIR Idriss Master Student Chad MS
TEHOU Aristide PhD Student Benin PhD
TEKA S. Oscar BS & PhD Student Benin PhD
TOKO IMOROU Ismaïla PhD Student Benin PhD
TOKO MOUHAMADOU Inoussa PhD Student Benin PhD
VIHOTOGBE Romaric PhD Student Benin PhD
VODOUHE G. Fifanou PhD Student Benin PhD
YAOÏTCHA Alain PhD Student Benin PhD
ZANNOU Afio PhD Student PhD
ZOFFOUN G. Alex PhD Student PhD
ZOUMANA Goïta Master Student Mali MS

 

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LAST UPDATED ON: May 7, 2019

 

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  • Building of the Laboratory of Applied Ecology (LEA). (Credit photo: Dr Akomian Fortuné Azihou / LEA, Abomey-Calavi, Benin, October 2018)
    Building of the Laboratory of Applied Ecology (LEA). (Credit photo: Dr Akomian Fortuné Azihou / LEA, Abomey-Calavi, Benin, October 2018)
  • Brousse tigrée (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Bâtiment Professeur Nestor SOKPON (en haut à gauche), bâtiment des volontaires (en bas à gauche), bâtiment Dr KASSA (à droite). (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Système agroforestier à Faidherbia albida. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Mare-Bali (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Odo Octhèrè (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • FM Deve (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Système Agroforestier à palmier à huile. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Vue globale des 5 bâtiments du Laboratoire d’Ecologie Appliquée (LEA). (Photo credit: Dr Akomian Fortuné Azihou / LEA, Octobre 2018)
  • Bâtiment Professeur Nestor SOKPON (à droite), bâtiment des volontaires de l'UAC (à gauche). (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Vue globale des bâtiments du Laboratoire d’Ecologie Appliquée (LEA). (Photo credit: Dr Akomian Fortuné Azihou / LEA, Octobre 2018)
  • Lokoli (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Cascade de Tanongou (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)
  • Musée de Zoologie BIOTA et bâtiment Professeur Mama Adamou N'DIAYE. (Photo credit: Dr Akomian Fortuné Azihou / Laboratoire d’Ecologie Appliquée (LEA), Octobre 2018)