Nutrient Distribution in the Basement Complex Soils of the Tropical, Dry Rainforest of Southwestern Nigeria

Valley bottom soils of the sub-humid tropical Southwestern Nigeria on basement complex: Characteristics and classification

“…With a range of 3.3 to 40.0#g g-1 of 0.1 N HC1 extractable Zn and of 1.4 to 9.1 #g g-1 Cu, the soils were adequately supplied with Zn and Cu and there was no likelihood of Zn or Cu deficiency in the soils, confirming Fagbami et al (1985b) findings. Fe and Mn deficiency was also unlikely in these soils nor was there any likelihood of toxicity from these elements with the present values of the elements: 18.2 to 245.0 #g g-1 Fe and 1.7 to 109.0#g g-1 Mn and the slightly acid to neutral soil reaction.…”

“…The soils are slightly acid to neutral (pH in water of 6.0 to 7.4 in all horizons), being generally better supplied with exchangeable cations (Kyuma 1985), especially the more mobile cations Ca and Mg than the upland soils (Fagbami et al 1985a) (Table 3).…”

Biosolids conditioning and the availability of Cu and Zn for rice

“…The extraction methods that utilize DTPA and Mehlich's-3 are less operational when compared to the HCl 0.1 mol L -1 method, because more time and work have to be dedicated to prepare those extractors, they require a longer agitation time, and extract filtering is slower. In addition, the DTPA removal capacity depends on various factors such as pH (Camargo et al, 1982) and soil mineralogy (Fagbami et al, 1985). In this present study, the correlation coefficient values were in closely proximity (Table 4) indicating their efficiency was identical; however we chose to indicate the use of HCl 0.1 mol L -1 because this method is more operational.…”

“…The biosolid produced presented a pH varying between 10 and 13, what increased the pathogen control and decreased the heavy metal availability by precipitation and/or occlusion at the crystalline layer of iron amorphous hydroxide that was created. The greatest disadvantage of the residue alkalinization is the possibility of its addiction to cause soil salinity (Cripps & Matocha, 1991;Fine et al 1989), and contamination of the underground water by nitrate produced by organic matter degradation associated to high soil pH (Anjos, 1999;Oliveira, 2000). Some MSTPs substituted the chemical conditioning by the industrial polymer addiction, known as polyelectrolytes too.…”