Table 1.

Soil characteristics of the different sites used in this study.

Locations	Conditions	Texture	pH(H2O)	Fe Content	Latitude and Longitude	References
Edozhigi, Nigeria	Fe-toxic	clay loam	4.3	1230 mg kg−1	9°4′ 38.47 N 6°3′ 6.73” E	Abah et al. (2012)
Suakoko, Liberia	Fe-toxic	Sandy loam	5.2	489 mg kg−1	7°00′ 33” N 9°34′ 34” W	AfricaRice (unpublished data)
Valley du Kou, Burkina Faso	Fe-toxic	Silt loam	6.1	295 mg kg−1	11°11′ 30” N 4°18 36” W	Narteh and Sahrawat (1999)
Rokupr, Sierra Leone	Fe-toxic	Clay	5.7	548 mg kg−1	9°00′ 42” N 12°57′ 13” W	AfricaRice (unpublished data)
Ibadan, Nigeria	Control	Clay	7.0	84 mg kg−1	7°25′ 56” N 4°00′ 07” E	Ande (2014)