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Hétérogénéité spatiale et fonctionnelle de la surface du sol et son influence sur la production du niébé dans les exploitations familiales au Niger

Abstract : Heterogeneity is a major feature of soil surface in the Sahelian zone. This work was carried out in two Sahelian regions of Niger (Tillaberi and Maradi) with different agroecological, pedoclimatic and socio-economic conditions related to cowpea cultivation. It aimed to understand the influence of spatial and functional heterogeneity of soil surface on cowpea production.Our methodological approach is based on semi-directive surveys conducted on cowpea producers, mapping and characterization of physicochemical properties of homogeneous soil surface, as well as field monitoring of hydrodynamic properties and cowpea yield parameters during two growing seasons. The collected data allowed gathering local knowledge on soil surface heterogeneity and ranking of homogeneous surface according to their productive potential and their fertility levels. The types of homogeneous surface identified in this study are those related to surface features changes, including crusting, changes in microtopography, and vegetation cover. They comprised the homogeneous surface features related to erosion crusts (ERO), deposition crusts (DEC), wind erosion crusts around Guiera senegalensis (EOL-GS), structural crusts under the crown of Faidherbia albida (ST-FA), structural crusts associated with anthills (ST-F), structural crusts (ST-SN), deposition crusts on alluvial soils (DEC-AL) and deposition crusts on alluvial soils under the crown of Faidherbia albida (DEC- AL-FA). The nature and spatial arrangement of these homogeneous soil surfaces within plots vary by region and soil type. The most representative homogeneous soil surfaces are related to structural crusts on tropical ferruginous soils in Tillabéri and alluvial deposition crusts on alluvial soils in Maradi. The greatest values for carbon, nitrogen, phosphorus, exchangeable bases and cation exchange capacity were measured on DEC on tropical ferruginous soils and DEC-AL-FA on alluvial soils. The lowest values were obtained on ST-SN and ERO. The greatest values of soil water retention capacity and useful water reserve were recorded on DEC. The greatest values of saturation hydraulic conductivity (Ks) were measured on the EOL-GS (64.4 mm.h-1) and the lowest on DEC (2.7 mm.h-1) and ERO (5.3 mm.h-1). These values decreased during both cropping seasons following the cumulative rainfall received after tillage and according to the dynamics of crusts evolution on the different homogeneous surface. The nodulation and residues and grains yields of cowpea varieties are higher on ST-FA at sites of Tillaberi and at ST-F at sites of Maradi. The ERO and ST-SN were identified as a types of homogeneous soil surface with constraints, i.e. with the lowest nodules number and residues and grains yields. Organic manure application on these surfaces resulted in the improvement of their physico-chemical and water properties, and also a significant increase in nodulation and residues and grains yields. The resulting yield exceed those obtained in a peasant environment in Niger which varies between 120 and 400 kg/ha depending on the variety.The results of this study may help in integrating soil surface heterogeneity to optimize cowpea production on Sahelian soils.
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https://hal.univ-reims.fr/tel-03494989
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Submitted on : Monday, December 20, 2021 - 10:08:21 AM
Last modification on : Tuesday, January 4, 2022 - 5:59:37 AM

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  • HAL Id : tel-03494989, version 1

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Bachirou Seyni Bodo. Hétérogénéité spatiale et fonctionnelle de la surface du sol et son influence sur la production du niébé dans les exploitations familiales au Niger. Sciences de la Terre. URCA - GEGENAA, 2019. Français. ⟨tel-03494989⟩

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