1. Akpan-Idiok AU, Ogbaji PO (2013) Characterization and classification of Onwu River Floodplain soils in Cross River State Nigeria. Int Jour of Agric Res 8(3):107–1222
2. Benites VM, Polidoro JC, Carvalho MCS, Resende AV, Bernardi ACC, Álvares FA (2010) O potássio, o cálcio e o magnésio na agricultura brasileira. In: Prochnow LI (ed) Boas práticas para uso eficiente de fertilizantes. IPNI, Piracicaba
3. Bogdanovic D, Ubavic M, Hadžic V (1997) Heavy metals in soil. In: Kastori R (ed) Heavy metals in environment. Institute of Field and Vegetable Crops: Novi Sad, Serbia, pp 97–193
4. Chen ZC, Ma JF (2012) Magnesium transporters and their role in Al tolerance in plants. Plant Soil. https://doi.org/10.1007/s11104-012-1433-y
5. Cools N, De Vos B (2016) Part X: sampling and analysis of soils. In: UNECE ICP Forests Programme Cordinating Centre: manual on methods and criteria for harmonized sampling, assessment, monitoring and analysis of the effect of air pollution on forests. Thunen Institute of Forest Ecosystems, Eberswalde