Distribution of Phosphorus Fractions down the Soil Depth in the Savanna Zone of Nigeria

A. O. Ojo, V. O. Aduramigba-Modupe, O. D. Adeoyolanu, O. A. Denton, A. O. Oyedele, A. O. Tayo-Aruna, I. O. Fademi

Abstract


The distribution of phosphorus (P) fractions down the soil depth varies depending on the soil type as being affected by the surrounding soil management practices. A 10 km by 10 km site was chosen in the savanna zone of Nigeria for the study. Modal soil profile pits were dug to identify the different soil types while soil sampling was done at 0-20 cm, 20-40 cm, 40-80 cm and 80-120 cm depth. Resin P was the largest extractable P fraction while residual P was the least in the soil series characterized, down the soil depth. Fractionation results showed that there was variation down the soil depth. The conc. HCl-Pi was not observed at the 0-20 cm depth, NaHCO3-Pi and Po was small while NaOH-Pi and Po was observed at this depth. Initial decrease at the 20-40 cm depth was observed for most of the P fractions while more of the P fractions were observed at the 40-80 cm depth. The values observed at the 80-120 cm depth was however small compared to other soil depth. Resin P was the sink of P and would serve as a reserve of P in the soil series. However, organic and inorganic P extractable with NaOH i.e. NaOH Pi and Po which were high at the 0-20 cm depth would be mainly responsible for the availability of P in the soil solution for plant uptake.


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DOI: https://doi.org/10.5539/jas.v9n9p94

Copyright (c) 2017 A. O. Ojo

License URL: http://creativecommons.org/licenses/by/4.0

Journal of Agricultural Science   ISSN 1916-9752 (Print)   ISSN 1916-9760 (Online)  E-mail: jas@ccsenet.org

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