S. Brown, J. M. Anderson, P. L. Woomer, M. J. Swift, and E. Barrios, Soil biological processes in tropical ecosystems The Biological Management of Tropical Soil Fertility, 1994.

S. Brown and A. E. Lugo, ABSTRACT, Journal of Tropical Ecology, vol.9, issue.01, pp.1-32, 1990.
DOI : 10.1146/annurev.es.18.110187.002243

A. Buerkert and P. Hiernaux, Nutrients in the West African Sudano-Sahelian zone: Losses, transfers and role of external inputs, Zeitschrift f??r Pflanzenern??hrung und Bodenkunde, vol.57, issue.3-4, pp.365-383, 1998.
DOI : 10.1002/jpln.1998.3581610405

A. Buerkert, J. P. Lamers, G. H. Schmelzer, K. Becker, and H. Marschner, PHOSPHORUS AND MILLET CROP RESIDUE APPLICATION AFFECT THE QUANTITY AND QUALITY OF MILLET LEAVES AND FODDER WEEDS FOR RUMINANTS IN AGRO-PASTORAL SYSTEMS OF THE SAHEL, Experimental Agriculture, vol.33, issue.3, pp.253-263, 1997.
DOI : 10.1017/S0014479797003074

M. K. Cao and F. I. Woodward, Net primary and ecosystem production and carbon stocks of terrestrial ecosystems and their responses to climate change, Global Change Biology, vol.4, issue.2, pp.185-198, 1998.
DOI : 10.1046/j.1365-2486.1998.00125.x

R. Catinot, Aménager les savanes boisées africaines, Bois et Forêts des Tropiques, vol.241, pp.53-69, 1994.

J. César, La production biologique des savanes de Côte d'Ivoire et son utilisation par l'homme, 1992.

J. César, Z. Coulibaly, M. Denich, M. Kanashiro, and P. L. Vlek, Conséquence de l'accroissement démographique sur la qualité de la jachère References The potential and dynamics of carbon sequestration in traditional and modified fallow systems of the eastern Amazon region, Brazil Global Climate Change and Tropical Ecosystems, pp.213-229, 1993.

L. Derouard, C. Villenave, P. Lavelle, and D. Masse, Evolution de la macrofaune du sol au cours d'un hivernage dans des jachères d'âges différents au Sénégal, Raccourcissement du temps de jachère, biodiversité et développement durable en Afrique Centrale (Cameroun) et en Afrique de l'Ouest (Mali, Sénégal). Final report. Comm. des Communautés européennes. Contrat TS3-CT93-0220 (DG 12 HSMU), and IRD Paris, pp.139-145, 1998.

A. Derouw, Gestion de la fertilité du sol sur un terroir sahélien. Fumure animale, matière organique et encroûtement superficiel du sol dans les systèmes de culture de mil, pp.63-70, 1998.

P. V. Desanker, P. G. Frost, C. O. Justice, and R. J. Scholes, The Miombo Network: Framework for a Terrestrial Transect Study of Land-Use and Land-Cover Change in the Miombo Ecosystems of Central Africa, The International Geosphere-Biosphere Programme (IGBP), 1995.

R. P. Detwiler, Land use change and the global carbon cycle: the role of tropical soils, Biogeochemistry, vol.199, issue.1, pp.67-93, 1986.
DOI : 10.1007/BF02186966

M. Diouf, Diagnostic agronomique en parcelles paysannes Une méthode d'amélioration des systèmes de culture In: Savanes d'Afrique, Terres Fertiles ?, pp.10-14, 1990.

P. Donfack, C. Floret, and R. Pontanier, Secondary succession in abandoned fields of dry tropical Northern Cameroon, Journal of Vegetation Science, vol.28, issue.4, pp.499-508, 1995.
DOI : 10.2307/3236348

P. Duchaufour, Pédogenèse et Classification, 1983.

E. Dufrène, R. Ochs, and B. Saugier, Oil palm photosynthesis and productivity linked to climatic factors, Oléagineux, vol.4589, pp.345-355, 1990.

P. Dugué, Utilisation des résidus de récolte dans un système agro-pastoral sahélo-soudanien au Yatenga (Burkina-Faso) In: Relations Agriculture-Elevage, pp.10-13, 1985.

P. Dugué, Gestion de la fertilité et stratégies paysannes Le cas des zones de savanes d'Afrique de l'Ouest, Agriculture et Développement, vol.18, pp.13-20, 1998.

P. Dugué, Les transferts de fertilité dus à l'élevage en zone de savane, Agriculture et Développement, vol.18, pp.99-107, 1998.

P. Dugué, Flux de biomasse et gestion de la fertilité à l'échelle des terroirs Etude de cas au Nord Cameroun et essai de généralisation aux zones de savane d'Afrique sub-saharienne, 2000.

P. N. Egharevba and . Undated, A review of millet work at the Institute for Agricultural Research of Samaru

B. H. Ellert and J. R. Bettany, Calculation of organic matter and nutrients stored in soils under contrasting management regimes, Canadian Journal of Soil Science, vol.75, issue.4, pp.529-538, 1995.
DOI : 10.4141/cjss95-075

H. Eswaran, E. Van-den-berg, and P. Reich, Organic Carbon in Soils of the World, Soil Science Society of America Journal, vol.57, issue.1, pp.192-194, 1993.
DOI : 10.2136/sssaj1993.03615995005700010034x

S. Fall, Impact de deux espèces de termites à régime alimentaire différencié sur la matière organique et le compartiment microbien de termitières, 1998.

S. Fanchette, Colonisation des terres sylvo-pastorales et conflits fonciers en Haute-Casamance, Pastoral Land Tenure Series, 1999.

S. Fanchette, Densit?? de population et intensification agro-pastorale en Haute-Casamance, Espace, populations, soci??t??s, vol.17, issue.1, pp.67-81, 1999.
DOI : 10.3406/espos.1999.1870

P. M. Fearnside and R. I. Barbosa, Soil carbon changes from conversion of forest to pasture in Brazilian Amazonia, Forest Ecology and Management, vol.108, issue.1-2, pp.147-166, 1998.
DOI : 10.1016/S0378-1127(98)00222-9

C. Feller, Une méthode de fractionnement granulométrique de la matière organique des sols, 1979.

C. Feller, Transformation de résidus de récolte marqués (pailles 14C 15N, compost 14C) et devenir de l'azoteengrais (15N-urée) dans un agrosystème tropical, 1981.

C. Feller, Organic inputs, soil organic matter and functional soil organic compartments in lowactivity clay soils in tropical zones, Soil Organic Matter Dynamics and Sustainability of Tropical Agriculture. Proceedings of an International Symposium, pp.4-6, 1991.

C. Feller, La matière organique dans les sols tropicaux à argile 1:1. Recherche de compartiments fonctionnels. Une approche granulométrique, Collection TDM ORSTOM, vol.144, issue.393, 1995.

C. Feller, La matière organique du sol et la recherche d'indicateurs de la durabilité des systèmes de culture dans les régions tropicales semi-arides et subhumides d'Afrique de l'Ouest, Sustainable Land Management in African Semi-Arid and Subhumid Regions. Proceedings of the SCOPE Workshop, pp.15-19, 1993.

C. Feller, J. Balesdent, B. Nicolardot, and C. Cerri, Approaching "functional" soil organic matter pools through particle-size fractionation. Examples for tropical soils Advances in Soil Science, 2000.

C. Feller and M. H. Beare, Physical control of soil organic matter dynamics in the tropics, Geoderma, vol.79, issue.1-4, pp.69-116, 1997.
DOI : 10.1016/S0016-7061(97)00039-6

C. Feller, J. L. Chopart, and F. Dancette, Effet de divers modes de restitution de pailles de mil sur le niveau et la nature du stock organique dans deux sols sableux tropicaux (Sénégal), Cahiers ORSTOM Série Pédologie, vol.23, issue.3, pp.237-252, 1987.

C. Feller, F. Ganry, and M. Cheval, Décomposition et humification des résidus végétaux dans un agrosystème tropical. I. Influence d'une fertilisation azotée (urée) et d'un amendement organique (compost) sur la répartition du carbone et de l'azote dans différents compartiments d'un sol sableux, Agronomie Tropicale, vol.36, issue.1, pp.9-17, 1981.

C. Feller and P. Milleville, Evolution des sols de défriche récente dans la région des Terres Neuves (Sénégal Oriental). I: Présentation de l'étude et évolution des principales caractéristiques morphologiques et physico-chimiques, Cahiers ORSTOM Série Biologie, vol.12, issue.3, pp.199-211, 1977.

P. Fernandes, Effet des modes de gestion des terres en zone sahélienne sur les termes et l'évolution de leur bilan organique et biologique: conséquences pour une production céréalière soutenue -Cas du Sénégal, 1999.

S. Fernandez-rivera, T. O. Williams, P. Hiernaux, and J. M. Powell, Faecal excretion by ruminants and manure availability for crop production in semi-arid West-Africa, 1994.

S. Rivera, T. O. Williams, and C. Renard, Livestock and Sustainable Nutrient Cycling in Mixed Farming Systems of Sub-Saharan Africa, Proceedings of an International Conference ILCA (International Livestock Centre for Africa), pp.22-26, 1993.

E. J. Fittkau, Structure, function and diversity of Central Amazonian ecosystems, Natural Resources and Resource Development, vol.4546, pp.28-41, 1997.

C. Floret, Raccourcissement du temps de jachère, biodiversité et développement durable en Afrique Centrale (Cameroun) et en Afrique de l'Ouest (Mali, Sénégal): Final Report. Comm. des Communautés Européennes. Contrat TS3-CT93-0220 (DG 12 HSMU), and IRD Paris, 1998.

C. Floret, R. Pontanier, and G. Serpantié, La Jachère en Afrique Tropicale, Man and Biosphere UNESCO, vol.16, issue.86, 1993.

R. Fogel, Roots as primary producers in below-ground ecosystems, Ecological Interactions in Soil. Plant, Microbes and Animals, pp.23-36, 1985.

A. Fournier, Cycle saisonnier de la biomasse herbacée dans les savanes de Ouango-Fitini. Annales de l'Université d, pp.63-94, 1982.

A. Fournier, Dans quelle mesure la production nette de matière végétale herbacée dans les jachères en savane soudanienne est-elle utilisable pour le pâturage, pp.2-4, 1996.

D. K. Friesen, I. M. Rao, R. J. Thomas, A. Oberson, and J. I. Sanz, Phosphorus acquisition and cycling in crop and pasture systems in low fertility tropical soils, Plant and Soil, vol.196, issue.2, pp.289-294, 1997.
DOI : 10.1007/978-94-009-0047-9_152

D. Frommel, Coup de chaleur sur la planète -Heatwave hits the planet, Le Monde Diplomatique, pp.22-23, 1999.

E. Gavinelli, C. Feller, M. C. Larre-larrouy, B. Bacye, N. Djegui et al., A routine method to study soil organic matter by particle???size fractionation: Examples for tropical soils, Communications in Soil Science and Plant Analysis, vol.312, issue.11-12, pp.11-12, 1995.
DOI : 10.1016/0167-8809(91)90124-G

K. E. Giller, M. H. Beare, P. Lavelle, A. M. Izac, and M. J. Swift, Agricultural intensification, soil biodiversity and agroecosystem function, Applied Soil Ecology, vol.6, issue.1, pp.3-16, 1997.
DOI : 10.1016/S0929-1393(96)00149-7

M. B. Gleave, The Length of the Fallow Period in Tropical Fallow Farming Systems: A Discussion with Evidence from Sierra Leone, The Geographical Journal, vol.162, issue.1, pp.14-24, 1996.
DOI : 10.2307/3060213

D. J. Greenland and P. H. Nye, INCREASES IN THE CARBON AND NITROGEN CONTENTS OF TROPICAL SOILS UNDER NATURAL FALLOWS, Journal of Soil Science, vol.45, issue.18, pp.284-299, 1959.
DOI : 10.1111/j.1365-2389.1959.tb02350.x

D. J. Greenland, A. Wild, and D. Adams, Organic matter dynamics in soils of the tropics -from myth to complex reality, Myths and Science of Soils of the Tropics, pp.17-33, 1992.

E. G. Gregorich, M. R. Carter, D. A. Angers, C. M. Monreal, and B. H. Ellert, Towards a minimum data set to assess soil organic matter quality in agricultural soils, Canadian Journal of Soil Science, vol.74, issue.4, pp.367-385, 1996.
DOI : 10.4141/cjss94-051

B. Grisi, C. Grace, P. C. Brookes, A. Benedetti, and M. T. Dell-abate, Temperature effects on organic matter and microbial biomass dynamics in temperate and tropical soils, Soil Biology and Biochemistry, vol.30, issue.10-11, pp.10-11, 1998.
DOI : 10.1016/S0038-0717(98)00016-9

H. Guérin, D. Richard, P. Lefevre, D. Friot, and N. Mbaye, Prévision de la valeur nutritive des fourrages ingérés sur parcours naturels par les ruminants domestiques sahéliens et soudaniens, INRA, issue.10, pp.4-11, 1989.

F. Gueye and F. Ganry, Recyclage des résidus de récolte par la voie fermentative Exemple de deux pailles: mil et maïs. International Foundation for Science -Institut, 1981.

K. Guillaume, L. Abbadie, A. Mariotti, and H. Nacro, Soil organic matter dynamics in tiger bush (Niamey, Niger). Preliminary results, Acta Oecologica, vol.20, issue.3, pp.185-195, 1999.
DOI : 10.1016/S1146-609X(99)80031-9

C. A. Hall and M. H. Hall, The efficiency of land and energy use in tropical economies and agriculture, Agriculture, Ecosystems & Environment, vol.46, issue.1-4, pp.1-30, 1993.
DOI : 10.1016/0167-8809(93)90010-M

J. M. Harmand and C. F. Njiti, Effets de jachères agroforestières sur les propriétés d'un sol ferrugineux et sur la production céréalière, Agriculture et Développement, vol.18, pp.21-29, 1998.

J. M. Harmand, C. F. Njiti, F. Bernhard-reversat, C. Feller, and R. Oliver, Variation des stocks de carbone dans le sol au cours du cycle jachère arborée -culture en zone soudanienne du Cameroun, La Jachère en Afrique Tropicale -Vol I. Actes du Séminaire International, pp.13-16, 1999.

L. Hatcher and E. J. Stepanski, A step-by-step approach to using the SAS System for univariate and multivariate statistics, SAS Institute Inc, vol.552, 1994.

P. F. Hendrix, D. A. Crossley, J. M. Blair, and D. C. Coleman, Soil biota as components of sustainable agroecosystems, Sustainable Agricultural Systems, pp.637-654, 1990.

J. E. Herrick and M. M. Wander, Relationships between soil organic carbon and soil quality in cropped and rangeland soils: The importance of distribution, composition, and soil biological activity, 1998.

P. Hiernaux, S. Fernandez-rivera, E. Schlecht, M. D. Turner, and T. O. Williams, Livestock-mediated nutrient transfers in Sahelian agro-ecosystems, 1997.

H. Hoefsloot and F. Vanderpol, Jachères Améliorées. Options pour le Développement des Systèmes de Production en Afrique de l'Ouest. Bulletins de l Royal Tropical Institute, Institut Royal des Tropiques, vol.333, issue.85, 1993.

R. A. Houghton, Land-use change and the carbon cycle, Global Change Biology, vol.222, issue.3, pp.275-287, 1995.
DOI : 10.1038/363234a0

N. R. Hulugalle, Long-term effects of land clearing methods, tillage systems and cropping systems on surface soil properties of a tropical Alfisol in S.W. Nigeria, Soil Use and Management, vol.84, issue.1, pp.25-30, 1994.
DOI : 10.1016/0167-1987(85)90013-3

A. Ickowicz, J. Usengumuremyi, A. Badiane, D. Richard, F. Colleye et al., Interactions entre jachère et systèmes d'alimentation des bovins en zone soudanienne du Sénégal: choix techniques et dynamique de développement (zone soudanienne, Sénégal), Jachère et Systèmes Agraires, pp.9-11, 1998.

A. Ickowicz, J. Usengumuremyi, D. Bastien, and N. De-choudens, Spatial analysis of land use by cattle herds in a village of the Sudanese zone in Senegal Application for grazing system improvement, 1997.

A. M. Izac, Developing policies for soil carbon management in tropical regions, Geoderma, vol.79, issue.1-4, pp.261-276, 1997.
DOI : 10.1016/S0016-7061(97)00044-X

A. M. Izac, Ecological economics of investing in natural resource capital in Africa In: Replenishing Soil Fertility in Africa, pp.237-251, 1997.

A. M. Izac and M. J. Swift, On agricultural sustainability and its measurement in small-scale farming in sub-Saharan Africa, Ecological Economics, vol.11, issue.2, pp.105-125, 1994.
DOI : 10.1016/0921-8009(94)90022-1

J. C. Jacquemard, Le Palmier à Huile. Le Technicien d'Agriculture Tropicale, 1995.

T. Jaffre, Evolution de la biomasse épigée et du stock de carbone d'une culture pérenne: le palmier à huile (Elaeis guineensis Jacq ORSTOM, 1984.

I. A. Jaiyeoba, Changes in soil properties related to different land uses in part of the Nigerian semi-arid Savannah, Soil Use and Management, vol.9, issue.3, pp.84-89, 1995.
DOI : 10.1007/BF00011027

D. S. Jenkinson and A. Ayanaba, Decomposition of Carbon-14 Labeled Plant Material Under Tropical Conditions1, Soil Science Society of America Journal, vol.41, issue.5, pp.912-915, 1977.
DOI : 10.2136/sssaj1977.03615995004100050020x

H. Jenny, S. P. Gessel, and F. T. Bingham, COMPARATIVE STUDY OF DECOMPOSITION RATES OF ORGANIC MATTER IN TEMPERATE AND TROPICAL REGIONS, Soil Science, vol.68, issue.6, pp.419-432, 1949.
DOI : 10.1097/00010694-194912000-00001

C. J. Jones, J. H. Lawton, and M. Shachak, Organisms as Ecosystem Engineers, Oikos, vol.69, issue.3, pp.373-386, 1994.
DOI : 10.2307/3545850

J. A. Jones, ABSTRACT, Journal of Tropical Ecology, vol.4, issue.03, pp.291-305, 1990.
DOI : 10.2307/1936687

M. J. Jones, The maintenance of soil organic matter under continuous cultivation at Samaru, Nigeria, The Journal of Agricultural Science, vol.11, issue.03, pp.473-482, 1971.
DOI : 10.1017/S001447970000449X

M. J. Jones, THE ORGANIC MATTER CONTENT OF THE SAVANNA SOILS OF WEST AFRICA, Journal of Soil Science, vol.2, issue.1, pp.42-53, 1973.
DOI : 10.1111/j.1365-2389.1973.tb00740.x

M. J. Jones and A. Wild, Soils of the West African Savanna, Technical Communications Commonwealth Agricultural Bureaux, vol.55, issue.246, 1975.

A. S. Juo, K. Franzluebbers, A. Dabiri, and B. Ikhile, Changes in soil properties during long-term fallow and continuous cultivation after forest clearing in Nigeria, Agriculture, Ecosystems & Environment, vol.56, issue.1, pp.9-18, 1995.
DOI : 10.1016/0167-8809(95)00635-4

A. S. Juo and A. Manu, Chemical dynamics in slash-and-burn agriculture, Agriculture, Ecosystems & Environment, vol.58, issue.1, pp.49-60, 1996.
DOI : 10.1016/0167-8809(95)00656-7

M. Kaïré, La production ligneuse des jachères et son utilisation par l'homme au Sénégal, 1999.

P. Kaiser, The role of soil micro-organisms in savanna ecosystems, Tropical Savannas, pp.541-557, 1983.

B. D. Kay, R. Lal, J. M. Kimble, R. F. Follett, and B. Stewart, Soil structure and organic carbon: a review, Soil Processes and the Carbon Cycle, pp.169-197, 1998.

A. Ker, Farming Systems in the African Savanna. A Continent in Crisis, International Development Research Centre (IDRC), vol.176, 1995.

C. T. Khombe, I. A. Dube, and P. Nyathi, The effects of kraaling and stover supplementation during the dry season on body weights and manure production of Mashona steers in Zimbabwe, African Livestock Research, vol.1, pp.18-23, 1992.

J. Kotto-same, P. L. Woomer, M. Appolinaire, and Z. Louis, Carbon dynamics in slash-and-burn agriculture and land use alternatives of the humid forest zone in Cameroon, Agriculture, Ecosystems & Environment, vol.65, issue.3, pp.245-256, 1997.
DOI : 10.1016/S0167-8809(97)00060-1

J. M. Kowal and A. H. Kassam, Agricultural Ecology of Savanna: a Study of West Africa, 1978.

L. Krogh, Field and village nutrient balances in millet cultivation in northern Burkina Faso: a village case study, Journal of Arid Environments, vol.35, issue.1, pp.147-159, 1997.
DOI : 10.1006/jare.1996.0159

G. Lambert, Les gaz à effet de serre, La Recherche, vol.243, pp.550-556, 1992.

J. Lamers, A. Buerkert, H. P. Makkar, M. Von-oppen, and K. Becker, Biomass Production, and Feed and Economic Value of Fodder Weeds as By-products of Millet Cropping in a Sahelian Farming System, Experimental Agriculture, vol.120, issue.03, pp.317-326, 1996.
DOI : 10.1007/BF00711209

M. Lamotte and F. Bourlière, Problèmes d'Ecologie: Structure et Fonctionnement des Ecosystèmes Terrestres, 1978.

M. Lamotte and F. Bourlière, Energy flow and nutrient cycling in tropical savannasEd.) Tropical Savannas, pp.583-603, 1983.

E. Landais and H. Guérin, Systèmes d'élevage et transferts de fertilité dans la zone des savanes africaines. I. La production des matières fertilisantes, Cahiers Agricultures, vol.1, pp.225-238, 1992.

E. Landais and P. Lhoste, L'association agriculture-élevage en Afrique Tropicale: un mythe techniciste confronté aux réalités du terrain, Cahiers des Sciences Humaines, vol.26, issue.12, pp.217-235, 1984.

A. Larbi, D. D. Dung, P. E. Olorunju, J. W. Smith, R. J. Tanko et al., Groundnut (Arachis hypogaea) for food and fodder in crop-livestock systems: forage and seed yields, chemical composition and rumen degradation of leaf and stem fractions of 38 cultivars, Animal Feed Science and Technology, vol.77, issue.1-2, 1999.
DOI : 10.1016/S0377-8401(98)00238-7

P. Lavelle, I. Barois, E. Blanchart, G. Brown, L. Brussaard et al., Earthworms as a resource in tropical agroecosystems, Nature & Resources, vol.34, issue.1, pp.26-41, 1998.

P. Lavelle, D. Bignell, M. Lepage, V. Wolters, P. Roger et al., Soil function in a changing world: the role of invertebrate ecosystem engineers, European Journal of Soil Biology, vol.33, issue.4, pp.159-193, 1997.

A. Lericollais and P. Milleville, La jachère dans les systèmes agropastoraux Sereer au Sénégal, La Jachère en Afrique de l'Ouest. Atelier International, pp.2-5, 1991.

M. Lopes-da-silva, K. Vielhauer, M. Denich, and P. L. Vlek, Can tree enrichment of secondary vegetation and fire-free land preparation by cutting, chopping and mulching improve the following crops ?, Proceedings of the Third Studies on Human Impact on Forests and Floodplains in the Tropics (SHIFT) Workshop, pp.15-19, 1998.

N. Z. Lupwayi and I. Haque, Leucaena hedgerow intercropping and cattle manure application in the Ethiopian highlands III. Nutrient balances, Biology and Fertility of Soils, vol.28, issue.2, pp.204-211, 1999.
DOI : 10.1007/s003740050484

A. Mando, Soil-dwelling termites and mulches improve nutrient release and crop performance on Sahelian crusted soil, Arid Land Research and Management, vol.12, issue.2, pp.153-163, 1998.
DOI : 10.1080/15324989809381505

A. Mando and L. Stroosnijder, The biological and physical role of mulch in the rehabilitation of crusted soil in the Sahel, Soil Use and Management, vol.75, issue.2, pp.123-127, 1999.
DOI : 10.1111/j.1475-2743.1999.tb00075.x

R. Manlay, Jachère et gestion de la fertilité en Afrique de l'Ouest: suivi de quelques indicateurs agro-écologiques dans deux sites du Sénégal, 1994.

R. Manlay, C. Cambier, A. Ickowicz, and D. Masse, Modélisation de la dynamique du statut organique d'un terroir ouest-africain par un système multi-agents, La Jachère en Afrique Tropicale -Vol I. Actes du Séminaire International, pp.13-16, 1999.

R. J. Manlay, P. Cadet, J. Thioulouse, and J. Chotte, Relationships between abiotic and biotic soil properties during fallow periods in the sudanian zone of Senegal, Applied Soil Ecology, vol.14, issue.2, pp.89-101, 2000.
DOI : 10.1016/S0929-1393(00)00052-4

URL : https://hal.archives-ouvertes.fr/hal-00427094

A. Martinez-yrizar, Biomass distribution and primary productivity of tropical dry forests Seasonally Dry Tropical Forests, pp.326-345, 1995.

D. Masse, A. Bodian, P. Cadet, J. Chotte, M. Diatta et al., Importance de divers groupes fonctionnels sur le fonctionnement de jachères courtes Rapport final, Projet CEE N° TS3-CT93-0220 (DG12 HSMU). Raccourcissement du Temps de Jachère, Biodiversité et Développement Durable en Afrique Centrale (Cameroun) et en Afrique de l'Ouest, pp.163-202, 1998.

D. Masse, F. Dembellé, L. Floc-'h, E. Yossi, and H. , Impact de la gestion des feux de brousse sur la qualité des sols des jachères de courte durée dans la zone soudanienne du Mali, Soil Fertility Management in West African Land Use Systems. Proceedings of the Regional Workshop, pp.4-8, 1997.

S. P. Mathur, The role of soil enzymes in the degradation of organic matter in the tropics, subtropics and temperate zones, Non-Symbiotic Nitrogen Fixation and Organic Matter in the Tropics. Transactions of the 12th International Congress of Soil Science, pp.8-16, 1982.

H. C. Meertens, L. O. Fresco, and W. A. Stoop, Farming systems dynamics: Impact of increasing population density and the availability of land resources on changes in agricultural systems. The case of Sukumaland, Tanzania, Agriculture, Ecosystems & Environment, vol.56, issue.3, pp.203-215, 1996.
DOI : 10.1016/0167-8809(95)00639-7

J. Menaut, R. Barbault, P. Lavelle, and M. Lepage, African savannas: biological systems of humification and mineralization, Ecology and Management of the World's Savannas. Australian Acad. Science, Canberra, pp.14-33, 1985.

J. Menaut and J. César, Structure and Primary Productivty of Lamto Savannas, Ivory Coast, Ecology, vol.60, issue.6, pp.1197-1210, 1979.
DOI : 10.2307/1936967

P. Milleville, Approche agronomique de la notion de parcelle en milieu traditionnel africain: la parcelle d'arachide en Moyenne-Casamance, Cahiers ORSTOM, Série Biologie, vol.17, pp.23-37, 1972.

H. Mohr and P. Schopfer, Plant Physiology, 1995.
DOI : 10.1007/978-3-642-97570-7

U. Mokwunye and L. L. Hammond, Myths and science of fertilizer use in the tropics Myths and Science of Soils of the Tropics, pp.121-134, 1992.

P. Mordelet, Influence des arbres sur la strate herbacée d'une savane humide (Lamto, Côte d'Ivoire), 1993.

C. Moureaux, Influence de la température et de l'humidité sur les activités biologiques de quelques sols ouest-africains, Cahiers ORSTOM, Série Pédologie, vol.5, issue.4, pp.393-420, 1967.

P. G. Murphy and A. E. Lugo, Ecology of Tropical Dry Forest, Annual Review of Ecology and Systematics, vol.17, issue.1, pp.67-88, 1986.
DOI : 10.1146/annurev.es.17.110186.000435

K. H. Murwira, M. J. Swift, and P. G. Frost, Manure as a key resource in sustainable agriculture, 1994.

J. M. Powell, S. Fernandez-rivera, T. O. Williams, and C. Renard, Livestock and Sustainable Nutrient Cycling in Mixed Farming Systems of Sub-Saharan Africa, Proceedings of an International Conference ILCA (International Livestock Centre for Africa), pp.22-26, 1993.

W. M. Mwangi, Low use of fertilizers and low productivity in sub-Saharan Africa, Nutrient Cycling in Agroecosystems, vol.29, issue.3, pp.135-147, 1997.
DOI : 10.1007/BF01991545

R. J. Myers, C. A. Palm, E. Cuevas, I. U. Gunatilleke, and M. Brossard, The synchronisation of nutrient mineralisation and plant nutrient demand The Biological Management of Tropical Soil Fertility, pp.81-116, 1994.

A. Naseem and V. Kelly, Macro trends and determinants of fertilizer use in Sub Saharan Africa. Rep. No. MSU International Development Working Paper 73, 1999.

D. A. Neher, Soil community composition and ecosystem processes -Comparing agricultural ecosystems with natural ecosystems, Agroforestry Systems, vol.45, issue.1/3, pp.159-185, 1999.
DOI : 10.1023/A:1006299100678

J. Ngamine and M. Altolna, Flux de biomasse et gestion de la fertilité à l'échelle des terroirs Etude de cas dans trois terroirs agro-pastoraux du sud du Tchad) Fertilité et relations -180 - References agriculture-élevage en zone de savane, pp.5-6, 1998.

P. H. Nye and D. J. Greenland, The Soil under Shifting Cultivation, Soil Science, vol.92, issue.5, 1960.
DOI : 10.1097/00010694-196111000-00024

E. P. Odum, The Strategy of Ecosystem Development, Science, vol.164, issue.3877, pp.262-270, 1969.
DOI : 10.1126/science.164.3877.262

F. O. Olasantan, Food production, conservation of crop plant biodiversity and environmental protection in the twenty-first century: the relevance of tropical cropping systems, Outlook on Agriculture, vol.28, issue.2, pp.93-102, 1999.

C. K. Ong, New ideas on soil formation, soil fertility, Agroforestry Today, vol.8, issue.3, 1996.

E. Pâte, Analyse spatio-temporelle des peuplements de nématodes phytoparasites dans les systèmes de culture à jachère du Sénégal, 1997.

A. Pavé, Modélisation en Biologie et en Ecologie, Aléas, vol.559, 1994.

R. Peltier, Les jachères à composante ligneuse. Caractérisation, productivité, gestion, La Jachère en Afrique de l'Ouest. Atelier International, pp.2-5, 1991.

R. Peltier and B. Pity, De la culture itinérante sur brûlis au jardin agroforestier en passant par les jachères enrichies, Bois et Forêts des Tropiques, vol.235, pp.49-57, 1993.

D. A. Perry, M. P. Amaranthus, J. G. Borchers, S. L. Borchers, and R. E. Brainerd, Bootstrapping in Ecosystems, BioScience, vol.39, issue.4, pp.230-237, 1989.
DOI : 10.2307/1311159

J. B. Peters and E. E. Schulte, Soil test survey of the Gambia: An overview, Communications in Soil Science and Plant Analysis, vol.25, issue.9-10, pp.9-10, 1994.
DOI : 10.1080/00103629109368402

C. Pieri and C. Pieri, Fertilité des Terres de Savanes Ministère de la Coopération -CIRAD Fertility of soils: A Future for Farming in the West African Savannah, 1989.

C. Potvin and D. A. Roff, Distribution-Free and Robust Statistical Methods: Viable Alternatives to Parametric Statistics, Ecology, vol.74, issue.6, pp.1617-1628, 1993.
DOI : 10.2307/1939920

J. F. Poulain, Crop residues in traditional cropping systems of West africa. Effects on the mineral balance and level of organic matter in soils. Proposals for their better management, p.181, 1977.

J. M. Powell, Assessment of dry-matter yield from grain yield in the West African Savannah Zone, The Journal of Agricultural Science, vol.1, issue.03, pp.695-698, 1984.
DOI : 10.1017/S0014479700006761

J. M. Powell, Manure for Cropping: A Case Study from Central Nigeria, Experimental Agriculture, vol.22, issue.01, pp.15-24, 1986.
DOI : 10.1071/AR9780631

J. M. Powell, S. Fernandez-rivera, P. Hiernaux, and M. D. Turner, Nutrient cycling in integrated rangeland/cropland systems of the Sahel, Agricultural Systems, vol.52, issue.2-3, pp.143-170, 1996.
DOI : 10.1016/0308-521X(96)00009-1

J. M. Powell and T. O. Williams, An overview of mixed farming systems in sub-Saharan Africa, 1994.

J. M. Powell, S. Fernandez-rivera, T. O. Williams, and C. Renard, Livestock and Sustainable Nutrient Cycling in Mixed Farming Systems of Sub-Saharan Africa, Proceedings of an International Conference ILCA (International Livestock Centre for Africa), pp.22-26, 1993.

M. E. Probert, J. R. Okalebo, and R. K. Jones, The Use of Manure on Smallholders' Farms in Semi-Arid Eastern Kenya, Experimental Agriculture, vol.21, issue.03, pp.371-381, 1995.
DOI : 10.1016/0308-521X(87)90038-2

C. Y. Prudencio, Ring management of soils and crops in the west African semi-arid tropics: The case of the mossi farming system in Burkina Faso, Agriculture, Ecosystems & Environment, vol.47, issue.3, pp.237-264, 1993.
DOI : 10.1016/0167-8809(93)90125-9

J. P. Quilfen and P. Milleville, Résidus de culture et fumure animale, aspect des relations agricultureélevage dans le Nord de la Haute-Volta. L'Agronomie Tropicale, pp.206-212, 1983.

F. Ramade, Ecologie des Ressources Naturelles. Collection Ecologie Appliquée et Sciences de l'Environnement, 1981.

D. Richard, B. Ahopke, V. Blanfort, and B. Pouye, Utilisation des zones agricoles et pastorales par les ruminants en zone soudanienne (Moyenne Casamance, Sénégal), Actes du Quatrième Congrès International des Terres de Parcours, pp.22-26, 1991.

E. Roose and B. Barthes, Organic matter management for soil conservation and productivity restoration in Africa: a contribution from French-speaking research

H. Ruthenberg, Farming Systems in the Tropics, 1971.

P. A. Sanchez, Soil productivity and sustainability in agroforestry systems Agroforestry: a Decade of Development, International Council for Research in Agroforestry, pp.205-223, 1987.

P. A. Sanchez and R. H. Miller, Organic matter and soil fertility management in acid soils of the tropics, XIII th Congress of the International Society of Soil Science, pp.13-20, 1986.

M. Sarr, C. Agboba, and A. Russell-smith, The effect of length of fallow and cultivation on termite abundance and diversity in the Sahelian zone of Senegal: A preliminary note, Pedobiologia, vol.42, pp.56-62, 1998.

K. G. Saxena and P. S. Ramakrishnan, Nitrification during slash-and-burn agriculture (Jhum) in North- Eastern India, Acta Oecologia, vol.7, issue.3, pp.307-319, 1986.

R. Schaefer, Activité métabolique du sol: fonctions microbiennes et bilans biogéochimiques dans la savane de Lamto, Bulletin de Liaison des Chercheurs de Lamto, vol.5, pp.167-184, 1974.

D. S. Schimel, Terrestrial ecosystems and the carbon cycle, Global Change Biology, vol.45, issue.1, pp.77-91, 1995.
DOI : 10.1007/BF00002772

K. Schleich, Le fumier peut-il remplacer la jachère ? Possibilité d'utilisation du fumier: exemple de la savane d'Afrique Occidentale. Revue d'Elevage et de Médecine Vétérinaire des, Pays Tropicaux, vol.39, issue.1, pp.97-102, 1986.

C. M. Shackleton, Annual production of harvestable deadwood in semi-arid savannas, South Africa, Forest Ecology and Management, vol.112, issue.1-2, pp.139-144, 1998.
DOI : 10.1016/S0378-1127(98)00321-1

R. P. Shukla and P. S. Ramakrishnan, Biomass allocation strategies and productivity of tropical trees related to successional status, Forest Ecology and Management, vol.9, issue.4, pp.315-324, 1984.
DOI : 10.1016/0378-1127(84)90016-1

P. Siband, Evolution des caractères et de la fertilité d'un sol rouge de Casamance, Agronomie Tropicale, vol.29, issue.12, pp.1228-1248, 1974.

L. Singh and J. S. Singh, Storage and Flux of Nutrients in a Dry Tropical Forest in India, Annals of Botany, vol.68, issue.3, pp.275-284, 1991.
DOI : 10.1093/oxfordjournals.aob.a088253

M. C. Sirois, H. A. Margolis, and C. Camire, Influence of remnant trees on nutrients and fallow biomass in slash-and-burn agroecosystems in Guinea, Agroforestry Systems, vol.40, issue.3, pp.227-246, 1998.
DOI : 10.1023/A:1006093329468

V. Smil, Crop Residues: Agriculture's Largest Harvest, BioScience, vol.49, issue.4, pp.299-308, 1999.
DOI : 10.2307/1313613

Y. Sokona, Greenhouse gas emission inventory for Senegal, Environmental Monitoring & Assessment, vol.38, issue.2-3, pp.291-299, 1991.

J. J. Stoorvogel and E. M. Smaling, Assessment of soil nutrient depletion in Sub, pp.1983-2000, 1990.

J. J. Stoorvogel, E. M. Smaling, and B. H. Janssen, Calculating soil nutrient balances in Africa at different scales, Fertilizer Research, vol.26, issue.3, pp.227-235, 1993.
DOI : 10.1007/BF00750641

J. J. Stoorvogel, E. M. Smaling, and B. H. Janssen, Calculating soil nutrient balances in Africa at different scales. II. District scale, Fertilizer Research, vol.35, pp.237-250, 1993.

M. Straskraba, S. E. Jorgensen, and B. C. Patten, Ecosystems emerging: 2. Dissipation, Ecological Modelling, vol.117, issue.1, pp.3-39, 1999.
DOI : 10.1016/S0304-3800(98)00194-X

P. Stromgaard, Biomass, growth, and burning of woodland in a shifting cultivation area of South Central Africa, Forest Ecology and Management, vol.12, issue.3-4, pp.163-178, 1985.
DOI : 10.1016/0378-1127(85)90089-1

P. Stromgaard, Early Secondary Succession on Abandoned Shifting Cultivator's Plots in the Miombo of South Central Africa, Biotropica, vol.18, issue.2, pp.97-106, 1986.
DOI : 10.2307/2388751

M. J. Swift and J. M. Anderson, Biodiversity and Ecosystem Function in Agricultural Systems, Biodiversity and Ecosystem Function, pp.15-41, 1994.
DOI : 10.1007/978-3-642-58001-7_2

M. J. Swift and P. Woomer, Organic matter and the sustainability of agricultural systems: definition and measurement, Soil Organic Matter Dynamics and Sustainability of Tropical Agriculture. Proceedings of an International Symposium, pp.4-6, 1991.

J. K. Syers, Managing soils for long-term productivity, Philosophical Transactions of the Royal Society B: Biological Sciences, vol.352, issue.1356, pp.1011-1021, 1356.
DOI : 10.1098/rstb.1997.0079

URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691985

J. K. Syers and E. T. Craswell, Role of soil organic matter in sustainable agricultural systems, Soil Organic Matter Management for Sustainable Agriculture, pp.24-26, 1994.

J. Thioulouse, D. Chessel, S. Dolédec, and J. M. Olivier, ADE-4: a multivariate analysis and graphical display software, Statistics and Computing, vol.7, issue.1, pp.75-83, 1997.
DOI : 10.1023/A:1018513530268

URL : https://hal.archives-ouvertes.fr/hal-00434994

H. Tiessen, E. Cuevas, and P. Chacon, The role of soil organic matter in sustaining soil fertility, Nature, vol.371, issue.6500, pp.783-785, 1994.
DOI : 10.1038/371783a0

H. Tiessen, C. Feller, E. V. Sampaio, and P. Garin, Carbon sequestration and turnover in semiarid savannas and dry forest, Climatic Change, vol.40, issue.1, pp.105-117, 1998.
DOI : 10.1023/A:1005342932178

H. Tiessen, I. H. Salcedo, and E. V. Sampaio, Nutrient and soil organic matter dynamics under shifting cultivation in semi-arid northeastern Brazil, Agriculture, Ecosystems & Environment, vol.38, issue.3, pp.139-151, 1992.
DOI : 10.1016/0167-8809(92)90139-3

O. P. Toky and P. S. Ramakrishnan, Secondary Succession Following Slash and Burn Agriculture in North-Eastern India: I. Biomass, Litterfall and Productivity, The Journal of Ecology, vol.71, issue.3, pp.735-745, 1983.
DOI : 10.2307/2259589

O. P. Toky and P. S. Ramakrishnan, Secondary Succession Following Slash and Burn Agriculture in North- Eastern India: II. Nutrient Cycling, The Journal of Ecology, vol.71, issue.3, pp.747-757, 1983.
DOI : 10.2307/2259590

H. Tomlinson, A. Traore, and Z. Teklehaimanot, An investigation of the root distribution of Parkia biglobosa in Burkina Faso, West Africa, using a logarithmic spiral trench, Forest Ecology and Management, vol.107, issue.1-3, pp.1-3, 1998.
DOI : 10.1016/S0378-1127(97)00340-X

O. Toussaint and E. D. Schneider, The thermodynamics and evolution of complexity in biological systems, Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, vol.120, issue.1, pp.3-11, 1998.
DOI : 10.1016/S1095-6433(98)10002-8

F. Van-der-pol, 5. Soil mining: An unseen contributor to farm income in southern Mali, Bulletin of the Royal Tropical Institute, vol.325, issue.47, 1992.
DOI : 10.3362/9781780445304.005

A. Van-wambeke, Soils of the Tropics. Properties and Appraisal, 1991.

K. Vielhauer, M. Kanashiro, T. D. Sa, and M. Denich, Technology development of slash-and-mulch and of fallow enrichment in shifting cultivation systems of the Eastern Amazon, Proceedings of the Third Studies on Human Impact on Forests and Floodplains in the Tropics (SHIFT) Workshop, pp.15-19, 1998.

H. I. Vierich and W. A. Stoop, Changes in West African Savanna agriculture in response to growing population and continuing low rainfall, Agriculture, Ecosystems & Environment, vol.31, issue.2, pp.115-132, 1990.
DOI : 10.1016/0167-8809(90)90214-X

B. H. Walker, Structure and function of savannas: an overview Ecology and Management of the World's Savannas, Australian Acad. Science, pp.83-91, 1985.

B. K. Watt and A. L. Merrill, Composition of foods. United States Department of Agriculture, 1963.

N. Webb, Installation Guide to the Root Washer Basic System. Delta-T Devices Ltd, 1995.

A. Wezel and R. Bocker, Mulching with branches of an indigenous shrub (Guiera senegalensis) and yield of millet in semi-arid Niger, Soil and Tillage Research, vol.50, issue.3-4, pp.3-4, 1999.
DOI : 10.1016/S0167-1987(99)00008-2

B. Wick, R. F. Kuhne, and P. L. Vlek, Soil microbiological parameters as indicators of soil quality under improved fallow management systems in south-western Nigeria, Plant and Soil, vol.202, issue.1, pp.97-107, 1998.
DOI : 10.1023/A:1004305615397

T. O. Williams, J. M. Powell, and S. Fernandez-rivera, Manure utilisation, drought cycles and herd dynamics in the Sahel: implications for cropland productivity, Livestock and Sustainable Nutrient Cycling in Mixed Farming Systems of Sub-Saharan Africa. Proceedings of an International Conference ILCA (International Livestock Centre for Africa), pp.22-26, 1993.

T. O. Williams, J. S. Powell, and . Fernandez-rivera, Soil fertility maintenance and food crop production in semi-arid West Africa: is reliance on manure a sustainable strategy ?, Outlook on Agriculture, vol.24, issue.1, pp.43-47, 1995.

M. Winter, WebElements. The Periodic Table on the WWW, 1993.

P. L. Woomer, The impact of cultivation on carbon fluxes in woody savannas of Southern Africa, Water, Air, & Soil Pollution, vol.47, issue.1-4, pp.403-412, 1993.
DOI : 10.1007/BF01105011

P. L. Woomer, C. A. Palm, J. N. Qureshi, and J. Kotto-same, Carbon sequestration and organic resource management in African smallholder agriculture, 1998.

D. J. Zarin, A. L. Duchesne, and M. Hiraoka, Shifting cultivation on the tidal floodplains of Amazonia: impacts on soil nutrient status, Agroforestry Systems, vol.41, issue.3, pp.307-311, 1998.
DOI : 10.1023/A:1006072421536

W. Zech, N. Senesi, G. Guggenberger, K. Kaiser, J. Lehmann et al., Factors controlling humification and mineralization of soil organic matter in the tropics, Geoderma, vol.79, issue.1-4, 1997.
DOI : 10.1016/S0016-7061(97)00040-2