Assessment of Two Toposequences in Forest- Savanna Transition Area for the Cultivation of Yam, Cassava and Maize in Eastern Nigeria

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International Journal of Research and Scientific Innovation (IJRSI) | Volume VII, Issue IX, September 2020 | ISSN 2321–2705

  Assessment of Two Toposequences in Forest- Savanna Transition Area for the Cultivation of Yam, Cassava and Maize in Eastern Nigeria

Asadu C.L.A*. and Okoro, E. K.
Department Of Soil Science and Land Resources Management, University of Nigeria Nsukka
*Corresponding author

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Abstract: The soils of two toposequences in the sub-humid tropical climate of Southeastern Nigeria were characterized and assessed for yam (Dioscorea spp.), cassava (Manihot esculenta) and maize (Zea mays) production in this study. Data were obtained following standard field and laboratory analytical procedures. Six profile pits were dug three on each toposequence described and samples from the pedogenic horizons were collected, processed and analyzed. The profiles located at Ekpe village toposequence were designated EUP, EMP, ETP for upper- , Mid- and Toe- slopes respectively. The corresponding profiles at Amadia village toposequence were designated AUP, AMP and ATP. The soils were generally deep, loose, slightly sticky and non-plastic. The dominant textural was sandy loam or loamy sand. The soils were generally acidic (pH < 5.6); The total nitrogen and available phosphorus contents exchangeable bases were generally low; soil organic matter contents were low to moderate but decreased down the profile depth. The soils met the morphological and physical requirements for the production of the three crops but chemical requirements were deficient with total N, available P and exchangeable K being the limiting nutrients. Thus, the soils were classified into S2f subclass due to these fertility constraints. Therefore for optimum production of the crops, application of compound mineral fertilizers such as NPK 20:10:10 or 15:15:15 at the rate of at least 300 kg ha-1 for yam, 250 kg ha-1 for cassava and 200 kg ha-1 for maize is recommended.

Keywords: Toposequence, forest-savannah, land evaluation, yam, cassava, maize.


The soil toposequence model is based on the catena concept, which comes from the Latin word ‘‘catena’’, meaning “chain”. This concept was developed in central Uganda to describe the close relationship between a sequence of soils in different positions in the landscape likened to ‘‘a chain of soils linked by topography’’ (Milne, 1935). The relationship between soils and physiographic features has been widely accepted by soil scientists and physiographers (Daniels, et al. 1970). Toposequence refers to a succession of soils from crest to a valley which contains a range of the soil profiles that are representative of the landscape and soils (Amhakhian and Achimugu, 2011). As the landscape is undulating, soil characteristics at different topographic positions also differ.