# Agroforestry for sustainable cocoa production in the forest-savannah transition zone in the north of the Congo Basin including Cameroon

Jean-Michel Harmand, Annemarijn Nijmeijer, Marie Sauvadet, Seguy Enock,

Jean-Daniel Essobo Nieboukaho, Eltson Eteckji Fonkeng, Pierre-Eric Lauri,

Patrick Jagoret, Stéphane Saj

► To cite this version:

Jean-Michel Harmand, Annemarijn Nijmeijer, Marie Sauvadet, Seguy Enock, Jean-Daniel Essobo Nieboukaho, et al.. Agroforestry for sustainable cocoa production in the forest-savannah transition zone in the north of the Congo Basin including Cameroon. FTA 2020 Science Conference: Forests, trees and agroforestry science for transformational change, Sep 2020, Bogor, Indonesia. pp.108-108. *hal-05177161*

HAL Id: hal-05177161

https://hal.science/hal-05177161v1

Submitted on 22 Jul 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

RESEARCH
PROGRAM ON
Forests, Trees and
Agroforestry

FTA 2020 Science Conference

Forests, trees and agroforestry
science for transformational change

14-18 | 21-25

September 2020

<figure><img src="image_4.png" /></figure>

Book of Abstracts

Corrigendum of 10.03.2021
FTA 2020 Science Conference

Forests, trees and agroforestry
science for transformational change

14-18 | 21-25

September 2020

Book of Abstracts
Book of Abstracts

© 2020 The CGIAR Research Program on Forests, Trees and Agroforestry (FTA)

<figure><img src="image_5.png" /></figure>

Content in this publication is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0), http://creativecommons.org/licenses/by/4.0/

DOI: 10.17528/cifor/007925

Gitz V, Meybeck A, Ricci F, Belcher B, Brady MA, Coccia F, Elias M, Jamnadass R, Kettle C, Larson A, Li Y, Louman B, Martius C, Minang P, Sinclair F, Sist P, Somarriba E. (Editors). 2020. *Book of Abstracts: FTA 2020 Science Conference - Forests, trees and agroforestry science for transformational change*. 14–18 | 21–25, September 2020. Bogor, Indonesia: The CGIAR Research Program on Forests, Trees and Agroforestry (FTA).

CGIAR Research Program on Forests, Trees and Agroforestry
CIFOR Headquarters
Jalan CIFOR
Situ Gede, Sindang Barang
Bogor Barat 16115
Indonesia

T +62-251-8622-622
E cgiarforestsandtrees@cgiar.org

foreststreesagroforestry.org

We would like to thank all funding partners who supported this research through their contributions to the CGIAR Fund. For a full list of the 'CGIAR Fund' funding partners please see: http://www.cgiar.org/our-funders/

Any views expressed in this publication are those of the authors. They do not necessarily represent the views of The CGIAR Research Program on Forests, Trees and Agroforestry (FTA), the editors, the authors' institutions, the financial sponsors or the reviewers.
<figure><img src="image_6.png" /></figure>

## AUTHORS

Harmand Jean-Michel†‡ Nijmeijer Annemarijn§l

Sauvadet MarieΔ Enock Seguy‡ Essobo Jean-Daniel

Fonkeng Eteckji Eltson‡ Lauri Pierre-Ericf

Jagoret Patrick§ Saj Stephane§

## E-MAIL ADDRESS OF PRESENTER

jean-michel.harmand@cirad.fr

j.harmand@cgiar.org

## ORGANIZATIONS

† CIRAD, Eco&Sols, Yaounde, Cameroon

‡ World Agroforestry, Yaounde, Cameroon

§ CIRAD, System, Montpellier, France

| IRAD, Yaounde, Cameroon

Δ IRD, Montpellier University, Eco&Sols, Montpellier, France

(f) INRA, System, Montpellier, France

# Agroforestry for sustainable cocoa production in the forest–savannah transition zone in the north of the Congo Basin including Cameroon

Past studies showed a gradual expansion of tree cover over savannah in the forest–savannah boundary zone of Cameroon (Gillet et al. 2001). While the encroachment of savannah by forest is more and more impeded by human activities, farmers have proven that afforestation at the border of the forest is achievable using cocoa and specific techniques to build up an associated tree canopy (Jagoret et al. 2012). Furthermore, mature cocoa agroforestry systems created on savannah (S-cAFS) and in forest (F-cAFS) seem to exhibit comparable multi-strata structure linked to a multi-purpose objective of farmers in terms of livelihoods and long-term sustainable management of cocoa. By combining measurements of cocoa production, litterfall and cycling, soil quality, carbon storage and tree species diversity along an age gradient (1 to 70 years), we showed that those variables in S- and F-cAFS generally tended to comparable levels after several decades. Results also emphasized the ability of S-cAFS to increase most of the ecosystem services (ES) although the time needed to reach levels found in F-cAFS varied strongly amongst variables (Nijmeijer et al. 2019a,b).

We also compared the impact of five shade tree species (*Canarium schweinfurthii*, *Dacryodes edulis*, *Milicia excelsa*, *Ceiba pentandra*, *Albizia adianthifolia*) and unshaded conditions on soil functions and cocoa yield in relation to plant functional traits and leaf litterfall within 8 cocoa farms 20 to 60 years old (Sauvadet et al. 2020). While no difference in cocoa yields could be detected between the different tree species and unshaded conditions because of high variability of data, the effects on soil functions varied largely among species. Shade tree species with the most dissimilar litter traits to cocoa (cocoa showing the lowest leaf litter quality) showed the largest improvement of soil functions. Low litter recalcitrance was strongly associated with increases in soil fertility indicators such as N and P availability, while pH, soil C and N contents increased with litter Ca restitution. Improvements of soil functions were low under the two fruit trees (*Canarium* and *Dacryodes*), medium under the legume tree *Albizia*, and high under the two timber trees (*Milicia* and *Ceiba*). According to the tree species and nutrient, nutrient recycling through litterfall could barely to largely offset the nutrient removal by cocoa beans and husks. This study corroborates that the two tall timber trees (*Milicia* and *Ceiba*) are some of the most appreciated companion species for cocoa production by farmers, alleging desirable light shade, higher soil fertility and cocoa yield.

In order to better assess the role of shade trees in these cocoa systems, future research will need to extend these approaches, especially to understand how plant diversity can help to adapt to climate change, including higher temperature and longer dry seasons.

## KEYWORDS

Cocoa agroforestry, ecosystem services, forest–savannah transition, plant functional traits, soil fertility

## REFERENCES

Gillet B, Achoundong G, Happi JY, Kabeyene-Beyala VK, Bonvallot J, Riera B, Mariotti A and Schwartz D. 2001. Agreement between floristic and soil organic carbon isotope (13C/12C, 14C) indicators of forest invasion of savannas during the last century in Cameroon. *Journal of Tropical Ecology* 17(6):809–832. https://doi.org/10.1017/S0266467401001614

Jagoret P, Michel-Dounias I, Snoeck D, Ngnogué HT and Malézieux E. 2012. Afforestation of savannah with cocoa agroforestry systems: A small-farmer innovation in central Cameroon. *Agroforestry Systems* 86:493–504. https://doi.org/10.1007/s10457-012-9513-9

Nijmeijer A, Lauri PE, Harmand JM and Saj S. 2019. Carbon dynamics in cocoa agroforestry systems in Central Cameroon: Afforestation of savannah as a sequestration opportunity. *Agroforestry Systems* 93:851–868. https://doi.org/10.1007/s10457-017-0182-6

Nijmeijer A, Lauri PE, Harmand JM, Freschet GT, Essobo Nieboukaho JD, Kenfack Fogang P, Enock S and Saj S. 2019. Long-term dynamics of cocoa agroforestry systems established on lands previously occupied by savannah or forests. *Agriculture, Ecosystems & Environment* 275:100–111. https://doi.org/10.1016/j.agee.2019.02.004

Sauvadet M, Saj S, Freschet, G, Essobo J-D, Enock S, Becquer T, Tixier P and Harmand J-M. 2020. Cocoa agroforest multifunctionality and soil fertility explained by shade tree litter traits. *Journal of Applied Ecology* 57(3):476–87. https://doi.org/10.1111/1365-2664.13560