Dynamics of Soil Porosity as Influenced by Some Soil Properties in a Tropical Humid Environment

K.I. Ofem, C.L.A. Asadu, P.I. Ezeaku, M.O. Eyong, C.P. Umeugokwe and C.E. Awaogu

Background and Objective: The dynamics of soil porosity is shaped and sometimes overwhelmed by other soil properties if proper soil management is not ensured. The effects of soil properties on soil porosity and the resultant implication were evaluated. Materials and Methods: Slope maps were generated from the digital elevation model obtained from United States Geological Survey Explorer SRTM 1 for three agrarian communities underlain by four geologic formations in Cross River State. Each slope range represented a mapping unit (8 mapping units were obtained) and 2 profile pits were sunk in each, resulting in 16 soil profile pits. Fifty-three soil samples were obtained from pedogenic horizons and used for analysis in the Soil Science Laboratory, University of Nigeria, Nsukka in 2019. Results: Bulk density (Bd) decreased with increasing total (St) and micro (Sμ) porosities. On the other hand, saturated hydraulic conductivity K_sat, the volume fraction of water at all tension levels (θvt) as well as exchangeable bases increased with increasing total and micro porosities. Conclusion: Exchangeable Na⁺, Bd and volume fraction of water at 30 cm of tension as well as lithology are important factors that influence soil porosity. The values of R² for models between St and Sμ, against Bd and θvt, were >50 %. Macro porosity was as a result, least influenced by other soil properties. Factor analysis further affirms the contributions of Bd, Na⁺ and volume fraction of water at 30 cm of tension to variation between lithologies for PC1 of St and Sμ.

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