Soil degradation is a major challenge in Sub-Saharan Africa, where integrated soil fertility management has been promoted to restore productivity. A long-term experiment (1972\uffe2\uff80\uff931992) run in Benin consisted of two phases: a depletion phase (1972\uffe2\uff80\uff931980) with varying levels of mineral and organic fertilisation, and a regeneration phase (1981\uffe2\uff80\uff931992) where all plots received full fertilisation and organic matter additions. Soils were sampled at 0\uffe2\uff80\uff9320\uffc2\uffa0cm depth in 1973, 1974, 1982, and 1989 to assess fertility changes. Mineral fertilisation (N, P, K) and plant biomass management (crop residue retention and biomass additions) significantly influenced seed cotton and maize grain yields during the depletion phase. Soil organic carbon declined consistently in all treatments during depletion but remained stable during regeneration. The long-term effect was evident only in seed cotton yield during depletion. In contrast, due to high variability, maize grain yield showed no consistent trend. The combined use of organic resources and mineral fertilisers helped maintain crop productivity but led to declining soil chemical properties in this Ferralsol. The analysis of this outdated yet unpublished dataset shed light on how long-term soil depletion effects persist over time, even when soil fertility management is restored, indicating a sort of \uffe2\uff80\uff98soil memory\uffe2\uff80\uff99. The persistence of these effect suggests that regenerative interventions must begin before critical thresholds of degradation are crossed. Future research should focus on alternative measures to restore/maintain soil fertility not evaluated in this experiment, such as conservation tillage or legume integration, to provide long-term benefits for smallholder farmers facing soil fertility challenges.Abstract. Long term fallow is no longer possible in densely populated tropical areas, but legume cover crops can help maintain soil fertility. Our work aimed to study changes in soil carbon in a sandy loam Ultisol in Benin, which involved a 12\uffe2\uff80\uff90year experiment on three maize cropping systems under manual tillage: traditional no\uffe2\uff80\uff90input cultivation (T), mineral fertilized cultivation (NPK), and association with Mucuna pruriens (M). The origin of soil carbon was also determined through the natural abundance of soil and biomass 13C. In T, NPK and M changes in soil carbon at 0\uffe2\uff80\uff9340 cm were \uffe2\uff88\uff920.2, +0.2 and +1.3 t C ha\uffe2\uff88\uff921 yr\uffe2\uff88\uff921, with residue carbon amounting to 3.5, 6.4 and 10.0 t C ha\uffe2\uff88\uff921 yr\uffe2\uff88\uff921, respectively. After 12 years of experimentation, carbon originating from maize in litter\uffe2\uff80\uff90plus\uffe2\uff80\uff90soil (0\uffe2\uff80\uff9340 cm) represented less than 4% of both total carbon and overall maize residue carbon. In contrast, carbon originating from mucuna in litter\uffe2\uff80\uff90plus\uffe2\uff80\uff90soil represented more than 50% of both total carbon and overall mucuna residue carbon in M, possibly due to accelerated mineralization of native soil carbon (priming effect) and slow mulch decomposition. Carbon originating from weeds in litter\uffe2\uff80\uff90plus\uffe2\uff80\uff90soil represented c. 10% of both total carbon and overall weed residue carbon in T and NPK. Thus mucuna mulch was very effective in promoting carbon sequestration in the soil studied.
", "keywords": ["Soil nutrients", "Carbon sequestration", "13C natural abundance", "[SDE] Environmental Sciences", "Soil management", "http://aims.fao.org/aos/agrovoc/c_7170", "Npk", "SOL CULTIVE", "F08 - Syst\u00e8mes et modes de culture", "Soil fertility", "Zea mays", "http://aims.fao.org/aos/agrovoc/c_875", "630", "plante de couverture", "Legume cover crops", "Benin", "http://aims.fao.org/aos/agrovoc/c_1301", "legume cover crop", "Mucuna pruriens", "http://aims.fao.org/aos/agrovoc/c_4971", "ANALYSE STATISTIQUE", "580", "LEGUMINEUSE TROPICALE", "Acrisol", "2. Zero hunger", "Tropical zones", "mucuna", "BIOMASSE", "http://aims.fao.org/aos/agrovoc/c_1936", "P35 - Fertilit\u00e9 du sol", "Green manure crops", "RESIDU VEGETAL", "http://aims.fao.org/aos/agrovoc/c_101", "04 agricultural and veterinary sciences", "15. Life on land", "Mucuna", "Soil carbon", "CARBONE ORGANIQUE", "soil organic carbon", "STOCK ORGANIQUE", "fertilit\u00e9 du sol", "MAIS", "http://aims.fao.org/aos/agrovoc/c_8504", "Farm/Enterprise Scale", "[SDE]Environmental Sciences", "FERTILISATION DU SOL", "0401 agriculture", " forestry", " and fisheries", "carbone"]}, "links": [{"href": "https://doi.org/10.1111/j.1475-2743.2004.tb00363.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Soil%20Use%20and%20Management", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1475-2743.2004.tb00363.x", "name": "item", "description": "10.1111/j.1475-2743.2004.tb00363.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1475-2743.2004.tb00363.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2004-06-01T00:00:00Z"}}, {"id": "11370/a5fba259-dd61-43ac-8b8a-86b2d5fd6cef", "type": "Feature", "geometry": null, "properties": {"updated": "2026-05-25T16:24:48Z", "type": "Journal Article", "created": "2025-08-20", "title": "Regenerating productivity after soil fertility depletion in a 20-year cotton\u2013maize rotation in Benin", "description": "AbstractSoil degradation is a major challenge in Sub-Saharan Africa, where integrated soil fertility management has been promoted to restore productivity. A long-term experiment (1972\uffe2\uff80\uff931992) run in Benin consisted of two phases: a depletion phase (1972\uffe2\uff80\uff931980) with varying levels of mineral and organic fertilisation, and a regeneration phase (1981\uffe2\uff80\uff931992) where all plots received full fertilisation and organic matter additions. Soils were sampled at 0\uffe2\uff80\uff9320\uffc2\uffa0cm depth in 1973, 1974, 1982, and 1989 to assess fertility changes. Mineral fertilisation (N, P, K) and plant biomass management (crop residue retention and biomass additions) significantly influenced seed cotton and maize grain yields during the depletion phase. Soil organic carbon declined consistently in all treatments during depletion but remained stable during regeneration. The long-term effect was evident only in seed cotton yield during depletion. In contrast, due to high variability, maize grain yield showed no consistent trend. The combined use of organic resources and mineral fertilisers helped maintain crop productivity but led to declining soil chemical properties in this Ferralsol. The analysis of this outdated yet unpublished dataset shed light on how long-term soil depletion effects persist over time, even when soil fertility management is restored, indicating a sort of \uffe2\uff80\uff98soil memory\uffe2\uff80\uff99. The persistence of these effect suggests that regenerative interventions must begin before critical thresholds of degradation are crossed. Future research should focus on alternative measures to restore/maintain soil fertility not evaluated in this experiment, such as conservation tillage or legume integration, to provide long-term benefits for smallholder farmers facing soil fertility challenges.