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Discoveries in Agriculture and Food Sciences - Vol. 12, No. 1
Publication Date: February 25, 2024
DOI:10.14738/dafs.121.16511.
Yéo, L., Tokapieu, M. G., & Ambéyin Touré, D. S. (2024). Qualities of Soil Upper Layers Under Rubber Plantation and Various
Previous Soil Histories in Zépréguhé (Daloa, west-central Côte d'Ivoire). Discoveries in Agriculture and Food Sciences, 12(1). 42-56.
Services for Science and Education – United Kingdom
Qualities of Soil Upper Layers Under Rubber Plantation and
Various Previous Soil Histories in Zépréguhé (Daloa, west-central
Côte d'Ivoire)
Lacina Yéo
University Jean Lorougnon Guédé Daloa, UFR Agroforestry,
Agrovalorisation Laboratory, BP 150 Daloa (Côte d’Ivoire)
Mekapeu Grace Tokapieu
University Jean Lorougnon Guédé Daloa, UFR Agroforestry,
Agrovalorisation Laboratory, BP 150 Daloa (Côte d’Ivoire)
Dogniméton Soro et Ambéyin Touré
University Jean Lorougnon Guédé Daloa, UFR Agroforestry,
Agrovalorisation Laboratory, BP 150 Daloa (Côte d’Ivoire)
ABSTRACT
This study focused on the diagnosis of soil fertility in Zépréguhé, a village located 8
km from Daloa in the center-west of Côte d'Ivoire. Four soil pits were planted
according to a toposequence oriented West-East under rubber and under previous
cultivation. All the pits have been described and soil samples in the 0-30 cm horizon
have been analysed at the plant and soil analysis laboratory of the Institute National
Polytechnique Félix Houphouet-Boigny in Yamoussoukro. The particle size, the
organic matter and the characteristics of the adsorbent complex were determined.
It emerges from this description and analysis that all soils in the study area are
ferralsols. The values obtained were compared to the critical thresholds in order to
determine the level of soil fertility. The results show that these soils, which appear
to be rich in organic matter, were really low in organic matter and very low in
acidity over the entire toposequence. Due to the crops in place, the upper slope and
Upper mid-slope positions accumulate badly decomposed organic matter.
Furthermore, the cation exchange capacity (CEC) is normal at the upper slope and
upper mid-slope and very low at the bottom of the slope. The sum of exchangeable
bases is small at the level of all the profiles. The soils of the study site have a low to
moderate level of fertility. Rubber and sorghum crops have better soil fertility and
particularly organic matter.
Keywords: Fertility, ferralsols, crop precedent, toposequence, Daloa, Côte d’Ivoire.
INTRODUCTION
In sub-Saharan Africa, population growth has led to an increase in food demand. Intensive
agriculture and the search for new fertile land result in pressure on the ecosystem, which, in
turn, leads to reduced soil fertility [1-2]. In most countries, soils have low fertility and exported
nutrients are not adequately replaced. Moreover, the practice of long-term fallow is tending to
disappear, giving way to short-term fallow and settled agriculture [3-4]. As a result, yields are
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Yéo, L., Tokapieu, M. G., & Ambéyin Touré, D. S. (2024). Qualities of Soil Upper Layers Under Rubber Plantation and Various Previous Soil Histories
in Zépréguhé (Daloa, west-central Côte d'Ivoire). Discoveries in Agriculture and Food Sciences, 12(1). 42-56.
URL: http://dx.doi.org/10.14738/dafs.121.16511
relatively low and land productivity decreases ([5-3]. Since soil is therefore the basis of all
agricultural production, knowledge of its physical and chemical potential is important for crop
development [6] For cultivated soils, the distribution of organic matter is likely to vary greatly
[7]. Such heterogeneity is a limiting factor in the proper match between the characteristics of
the soil and the doses of fertilizers to be applied to an agricultural plot. There is therefore an
interest in increasing and enhancing knowledge of soils, particularly for agricultural issues that
are ever increasing [8]. Thus, knowledge and mastery of the physical and chemical properties
of the soil are a prerequisite for good practice However, few people in West Africa and
especially in Côte d'Ivoire determine the soil fertility potential of their farm before its
development. If, according to the farmers, certain indicators make it possible to make a
diagnosis of fertility such as plants and animals that are indicators of soil fertility and the
biophysical state of the plot [10], these prove to be insufficient and often unreliable. to
determine the fertility potential of the soil. It is then necessary to resort to soil analysis in order
to specify the agricultural potential of its soil before its development [6].
The soils of the study area being moderately to strongly desaturated ferralitic soils (ferralsols)
are exposed to a rapid loss of their fertility potential [11]. Thus, the hypothesis underlying this
study is that soils under perennial cultivation would limit the loss of fertility less than those
under annual or seasonal cultivation.
The general objective of this study is to compare the level of soil fertility under perennial and
annual crops in Zépréguhé.
Specifically, it was a question of evaluating the physico-chemical characteristics of the surface
horizons of the soils under rubber and under different cropping precedents and deducing the
fertility of these soils.
MATERIALS AND METHODS
Location of the Study Site
The study was carried out in Zépreguhé (6°54'13''N and 6°21'51''W) 8 km from Daloa in the
Center-West of Côte d'Ivoire (Figure 1). The department of Daloa is characterized by a tropical
climate, with a very hot and dry period from November-March and a rainy period from April- October. Chromoleana and Imperata are the dominant grasses. The site has low slopes.
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Discoveries in Agriculture and Food Sciences (DAFS) Vol 12, Issue 1, February- 2024
Services for Science and Education – United Kingdom
Figure 1: Study area and plot location
Methods
Morpho-Pedological Characterization of the Soil:
Four cultural pits were opened on a toposequence oriented West – East starting from the
rubber plot, near the village in the lowlands (market gardening site). Each profile was identified
by its topographic position (HV: upper slope; MVinf: lower mid-slope, MVsup: upper mid-slope
and BP: lower slope). These soil pits have been described horizon after horizon. The
classification used is that of [12].
The characterization of the profiles took into account:
• the useful depth of the soil and the thickness of the layers were made by direct
measurement with a tape and by observation;
• the soil colour was determined using the Munsell code;
• the texture was made by observation in the field using the coil and ring method;
• the structure was determined by observing the organization and arrangement of soil
aggregates;
• the porosity was determined by observing the aggregates;
• biological activity was assessed by visual observation of the quality and number of roots
as well as microorganisms;
• the load of coarse elements was evaluated using the Munsell code;
• the organic matter content was assessed by visual observation;
• the humidity was assessed by direct visual observation of the horizons.