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Accueil du site → Doctorat → Allemagne → 2020 → Interactive tillage & crop residue management effects on soil properties, crop nutrient uptake & yield in different weathered soils of West Africa measurements, modelling & scenario simulations

Rheinischen Friedrich-Wilhelms-Universität Bonn (2020)

Interactive tillage & crop residue management effects on soil properties, crop nutrient uptake & yield in different weathered soils of West Africa measurements, modelling & scenario simulations

Nafi, Eeusha

Titre : Interactive tillage & crop residue management effects on soil properties, crop nutrient uptake & yield in different weathered soils of West Africa measurements, modelling & scenario simulations

Auteur : Nafi, Eeusha

Université de soutenance : Rheinischen Friedrich-Wilhelms-Universität Bonn

Grade : Dissertation 2020

Résumé partiel
Sustainable crop production intensification in West Africa is hampered by constraints such as soil degradation, mainly due to excessive mining of soil nutrients, topsoil loss by surface runoff, and climatic factors like excessive rainfall, droughts, and high temperature. To counteract this problem, alternative management practices need to be adopted that have the potential to prevent and/or reduce the severity of soil degradation and could be suitable for buffering the future extreme climate effects on crop production in a sustainable manner. Considering this fact, the overarching aim of our study was to identify management options to improve crop productivity and livelihood among the farming population in the Sudan Savanna of West Africa under current and future climate conditions by using monitoring data from long-term field experiments on several sites over 5 years and additional simulation experiments. Thus, this study was implemented stepwise : first, contour ridge tillage, reduced tillage, and crop residue management were assessed as an effective means to improve soil organic carbon stock, nutrient stocks, crop N uptake and N use efficiency (NUE) by setting up a field experiment on four sites [St1 : Ferric Lixisol, footslope in Dano (Burkina-Faso) ; St2 : Eutric Plinthosol, upslope in Dano (Burkina-Faso) ; St3 : Haplic Lixisols, footslope in Dassari (Benin) ; and St4 : Plinthic Lixisol, upslope in Dassari (Benin)] of West Africa from 2012 to 2016. On-farm trials were set up in a strip-split plot layout, where 2 levels of tillage (contour ridge tillage and reduced tillage) were considered as a main-plot factor, and sub-plot factors included 2 levels of crop residue management (with and without), and 2 levels of N fertilizer doses (control and recommended dose). In a second step, we calibrated and evaluated the CERES-Maize model in DSSAT and parameterized the tillage component of DSSAT using the experimental data of 2014 (calibration) and 2016 (validation). Finally, we used the calibrated model to assess the potential of contour ridge tillage and reduced tillage along with crop residue retention in terms of buffering the expected future climate change effects under a 2°C warming scenario on crop yield and to provide a site-specific assessment of best management practices. For this purpose, we used the HAPPI weather dataset consisting of three GCMs (ECHAM6, MIROC5, NorESM1), and two climate scenarios : current baseline (2006–2015), and 2°C warmer than pre-industrial levels.

Mots clés  : Westafrika, Bodenbearbeitung, Ernterückstandsmanagement, DSSAT, Anpassungen an den Klimawandel, West Africa, Tillage, Crop residue, Climate change adaptations

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Page publiée le 5 janvier 2021, mise à jour le 9 novembre 2021