Evaluation of gravel concentration and soil strength in upland rice cultivation in Abeokuta, Southwestern Nigeria FK Salako Department of Soil Science and Land Management University of Agriculture, PMB 2240, Abeokuta, Nigeria O Osiname WARDA Nigeria Station, c/o IITA, PMB 5320, Ibadan. Nigeria Abstract No Abstract.Nigerian Journal of Soil Sciences Vol. 16 (1) 2006: pp. 67-76 Requires Subscription PDF Published 2007-08-08 Issue Vol. 16 (2006) Section Articles Copyright for articles published in this journal is retained by the journal.