Plant and Soil

, Volume 269, Issue 1–2, pp 285–296 | Cite as

Senna siamea trees recycle Ca from a Ca-rich subsoil and increase the topsoil pH in agroforestry systems in the West African derived savanna zone

  • B. Vanlauwe
  • K. Aihou
  • B. K. Tossah
  • J. Diels
  • N. Sanginga
  • R. Merckx


The functioning of trees as a safety-net for capturing nutrients leached beyond the reach of crop roots was evaluated by investigating changes in exchangeable cations (Ca, Mg, and K) and pH in a wide range of medium to long term alley cropping trials in the derived savanna of West Africa, compared to no-tree control plots. Topsoil Ca content, effective cation exchange capacity, and pH were substantially higher under Sennasiamea than under Leucaena leucocephala, Gliricidia sepium, or the no-tree control plots in sites with a Bt horizon rich in exchangeable Ca. This was shown to be largely related to the recovery of Ca from the subsoil under Senna trees. The increase of the Ca content of the topsoil under Senna relative to the no-tree control treatment was related to the total amount of dry matter applied since trial establishment. The lack of increase in Ca accumulation under the other species was related to potential recovery of Ca from the topsoil itself and/or substantial Ca leaching. The accumulation of Ca in the topsoil under Senna had a marked effect on the topsoil pH, the latter increasing significantly compared with the Leucaena, Gliridia, and no-tree control treatments. In conclusion, the current work shows that the functioning of the often hypothesized ‘safety-net’ of trees in a cropping system depends on (i) the tree species and on (ii) the presence of a subsoil of suitable quality, i.e., clay enriched and with high Ca saturation.


Gliricidia sepium Leucaena leucocephala litterfall prunings soil pH subsoil Ca content 


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  1. Aihou, K, Vanlauwe, B, Sanginga, N, Lyasse, O, Diels, J, Merckx, R 1999Alley cropping in the moist savanna zone of West-Africa: I.Restoration and maintenance of soil fertility on ‘terre de barre’ soils in Southern Bénin RepublicAgroforest. Syst.42213227Google Scholar
  2. Cadisch, G, Rowe, E C, Noordwijk, M 1997Nutrient harvesting – The tree root safety netAgroforest. Forum83133Google Scholar
  3. Cadisch, G, Giller, K E 2000Soil organic matter management: The role of residue quality in carbon sequestration and nitrogen supplyRees, R MBall, BWatson, CCampbell, C eds. Sustainable Management of Soil Organic MatterCAB InternationalWallingford, UK97111Google Scholar
  4. Grimme, H, Juo, A S R 1985Inorganic nitrogen losses through leaching and denitrification in soils of the humid tropicsKang, B THeide, J eds. Nitrogen Management in Farming Systems in Humid and Subhumid TropicsInstitute for Soil FertilityHaren, The Netherlands5771Google Scholar
  5. Hauser, S 1993Root distribution of Dactyladenia (Acioa) barteri and Senna (Cassia) siamea in alley cropping on Ultisol. I. Implication for field experimentationAgrofest. Syst.24111121Google Scholar
  6. IITA1982Automated and Semi-automated Methods for Soil and Plant AnalysisInternational Institute of Tropical AgricultureIbadan, NigeriaManual series no. 7Google Scholar
  7. Jagtap, S S 1995Environmental characterization of the moist lowland savanna of AfricaKang, B TAkobundu, I OManyong, V MCarsky, R JSanginga, NKueneman, E A eds. Moist Savannas of Africa: Potentials and Constraints for Crop ProductionIITAIbadan, Nigeria930Google Scholar
  8. Nziguheba, G, Merckx, R, Palm, C A, Rao, M R 2000Organic residues affect phosphorus availability and maize yields in a Nitisol of western KenyaBiol. Fertility Soils32328339Google Scholar
  9. Palm, C A, Gachengo, C N, Delve, R J, Cadisch, G, Giller, K E 2001Organic inputs for soil fertility management in tropical agroecosystems: application of an organic resource databaseAgric. Ecosyst. Environ.832742Google Scholar
  10. Pierre, W H, Banwart, W L 1973Excess-base and excess-base/nitrogen ratio of various crop species and parts of plantsAgron. J.659196Google Scholar
  11. Salako, F K, Tian, G 2001Litter and biomass production from planted and natural fallows on a degraded soil in southwestern NigeriaAgroforest. Syst.51239251CrossRefGoogle Scholar
  12. Sanginga, N, Vanlauwe, B, Danso, S K A 1995Management of biological N2 fixation in alley cropping systems: estimation and contribution to N balancePlant Soil174119141CrossRefGoogle Scholar
  13. SAS1985SAS User’s Guide: Statistics5SAS Institute Inc.Cary, NC957Google Scholar
  14. SAS1992The MIXED procedureSAS Technical Report P-229: SAS/STAT Software: Changes and Enhancements. SAS Institute Inc.Cary, NC, USAGoogle Scholar
  15. Tang, C, Rengel, Z 2003Role of plant cation/anion uptake ratio in soil acidificationRengel, Z eds. Handbook of Soil AcidityMarcel Dekker Inc.New York, USA5781Google Scholar
  16. Tang, C, Yu, Q 1999Impact of chemical composition of legume residues and initial soil pH on pH change of a soil after residue incorporationPlant Soil2152938CrossRefGoogle Scholar
  17. Tian, G, Kang, B T, Brussaard, L 1992Biological effects of plant residues with contrasting chemical compositions under humid tropical conditions-decomposition and nutrient releaseSoil Biol. Biochemist.2410511060Google Scholar
  18. Tossah, B K, Zamba, D K, Vanlauwe, B, Sanginga, N, Lyasse, O, Diels, J, Merckx, R 1999Alley cropping in the moist savanna zone of West-Africa: II. Impact on soil productivity on a North-to-South transect in TogoAgroforest. Syst.42229244Google Scholar
  19. Van Breemen, N, Mulder, J, Driscoll, C T 1983Acidification and alkalinization of soilsPlant Soil75283308Google Scholar
  20. Vanlauwe, B, Sanginga, N, Merckx, R 1997Decomposition of four leucaena and senna prunings in alley cropping systems under sub-humid tropical conditions: The process and its modifiersSoil Biol. Biochemist.29131137Google Scholar
  21. Vanlauwe, B, Sanginga, N, Merckx, R 1998aSoil organic matter dynamics after addition of 15N labeled Leucaena and Dactyladenia residues in alley cropping systemsSoil Sci. Soc. Am. J.62461466Google Scholar
  22. Vanlauwe, B, Sanginga, N, Merckx, R 1998bRecovery of Leucaena and Dactyladenia residue 15N in alley cropping systemsSoil Sci. Soc. Am. J.62454460Google Scholar
  23. Vanlauwe, B, Diels, J, Duchateau, L, Sanginga, N, Merckx, R 1998cMineral N dynamics under bare and cropped Leucaenaleucocephala and Dactyladeniabarteri alley cropping systems after additions of 15N labeled residuesEurop. J. Soil Sci.49417425Google Scholar
  24. Vanlauwe, B, Wendt, J, Diels, J 2001Combined application of organic matter and fertilizerTian, GIshida, FKeatinge, J D H eds. Sustaining Soil Fertility in West-AfricaSSSA Special Publication Number 58Madison, USA247280Google Scholar
  25. Vanlauwe, B, Akinnifesi, F K, Tossah, B K, Lyasse, O, Sanginga, N, Merckx, R 2002aRoot distribution of Senna siamea grown on a series of soils representative for the moist savanna zone of Togo, West AfricaAgroforest. Syst.54112CrossRefGoogle Scholar
  26. Vanlauwe, B, Diels, J, Sanginga, N, Merckx, R 2002bIntegrated Plant Nutrient Management in Sub-Saharan Africa: From Concept to PracticeCABIWallingford, UK352Google Scholar
  27. Vanlauwe B, Diels J, Sanginga N and Merckx R 2004 Long-term integrated soil fertility management in Southwestern Nigeria: crop performance and impact on the soil fertility status. Plant Soil, In Press.Google Scholar
  28. Wichmann, W 1998IFA World Fertilizer Use ManualInternational Fertilizer Industry AssociationParis, FranceGoogle Scholar
  29. Wong, M T F, Gibbs, P, Nortcliff, S, Swift, R S 2000Measurement of the acid neutralizing capacity of agroforestry tree prunings added to tropical soilsJ. Agricult. Sci.134269276Google Scholar
  30. Wong, M T F, Swift, R S 2003Role of organic matter in alleviating soil acidityZ, Rengel eds. Handbook of Soil AcidityMarcel Dekker Inc.New York, USA.337358Google Scholar
  31. Yan, F, Schubert, S, Mengel, K 1996Soil pH increase due to biological decarboxylation of organic anionsSoil Biol. Biochemist.28617624Google Scholar

Copyright information

© Springer 2005

Authors and Affiliations

  • B. Vanlauwe
    • 1
  • K. Aihou
    • 2
  • B. K. Tossah
    • 3
  • J. Diels
    • 4
  • N. Sanginga
    • 1
  • R. Merckx
    • 5
  1. 1.Tropical Soil Biology and Fertility Institute of the International Centre for Tropical AgricultureB. VanlauweNairobiKenya
  2. 2.Institut National des Recherches Agricoles du BéninK. AihouCotonouBenin Republic
  3. 3.Institut Togolais de la Recherche AgronomiqueB.K. TossahLoméTogo
  4. 4.International Institute of Tropical AgricultureJ. DielsIbadanNigeria
  5. 5.Laboratory of Soil and Water ManagementFaculty of Agricultural and Applied Biological SciencesHeverleeBelgium

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