# Unravelling sustainable intensification in oil-palm agroforestry on Adja plateau, Benin

Rolland H. Yemadje, Hermione Koussihouèdé, Sylvain Rafflegeau

► To cite this version:

Rolland H. Yemadje, Hermione Koussihouèdé, Sylvain Rafflegeau. Unravelling sustainable intensification in oil-palm agroforestry on Adja plateau, Benin. 5. World Congress on Agroforestry WCA 2022, Jul 2022, Québec, Canada. Université de Laval, 1 p., 2022. [hal-05180108]

HAL Id: hal-05180108

https://hal.science/hal-05180108v1

Submitted on 23 Jul 2025

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# UNRAVELLING SUSTAINABLE INTENSIFICATION IN OIL PALM AGROFORESTRY ON ADJA PLATEAU, BENIN

Yèmadjè H. Rolland¹,²*, Koussihouèdé Hermione³, Rafflegeau Sylvain⁴,⁵

1 Soil Biology Group, P.O. Box 47, 6700 AA, Wageningen University, Wageningen, the Netherlands.

2 Knowledge, Technology and Innovation group, Wageningen University, Wageningen, The Netherlands.

3 UR Ecopédologie; Laboratoire de Sciences du sol; Faculté des Sciences Agronomiques, Université d'Abomey-Calavi, BP 526 Cotonou, Benin

4 CIRAD, UMR INNOVATION, F-34398 Montpellier, France

5 INNOVATION, Univ Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France

## 1. CONTEXT AND RESEARCH QUESTION

<figure><img src="image_3.png" /><figcaption>Traditional oil palm agroforestry system</figcaption></figure>

Fig 1: Landowners believe that oil palm fallow restore soil fertility.

Phase duration 10 years.

Landowners harvest oil palm bunch and palm wine.

Tenants believe that a mix of farmyard manure and mineral fertilizer (NPK) restore soil fertility. Phase duration 15 years.

Tenants harvest intercropped food crops.

**RQ:** When tenants intensify food crop production, is the intercropped phase of traditional oil palm agroforestry system, still sustainable regarding soil fertility management?

## 4. RESULTS

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

Earthworms cast and bulk density increased during the oil palm fallow phase. During intercropped phase, C and N soil content were stable, while P and K contents increased.

<figure><img src="image_5.png" /><figcaption>Fig 3: Gradient of maize yield in cropped fields</figcaption></figure>

30t/ha of farmyard manure produced the best maize yield equivalent to four times the control yield. Farmyard manure is the key point for food crop sustainable intensification.

## 2. STUDY SITE

<figure><img src="image_6.png" /><figcaption>Fig 2: Study site</figcaption></figure>

## 3. METHODOLOGY

Soil fertility assessed by earthworms' activity C, N, C/N, K and P contents

<figure><img src="image_7.png" /><figcaption>Fertilization of intercropped fields</figcaption></figure>

## 5. CONCLUSIONS

Sustainable intensification of food crop production is possible with trade-offs between organic & mineral fertilizers during intercropped phase.

<figure><img src="image_8.png" /><figcaption>Fig 4: Landowner gain more return as a result of the increase of the crops harvest.</figcaption></figure>

Less expenditure on NPK fertilizer for more harvest, so profitability!

In addition, the owner's oil palms are no longer vandalized

In addition, there is an increase in land access security.

**Acknowledgement:** Thanks to the 5th World Conference on Agroforestry for a General Support Grant.

<figure><img src="image_9.png" /></figure>

• 12 experimental fields
8 intercropped

• 4 oil palm fallows