Abstract
The major soils comprising the Gezira scheme are Hosh, Suleimi and Laota. These soils are dark grayish brown to dark brown, calcareous clays with < 1% organic matter.<p> The mineralogical data show that the soils of the Gezira scheme have similar sand, silt, and clay mineralogy. The uniform physiographic position and similar mineralogy of these soils indicate a common parent material. The similarity in mineralogical composition to that of recent sediments of the Blue Nile and its tributaries, supports the contention that the Ethiopian geology is the major, perhaps the sole "ancestor" of the soils of the Gezira scheme. The micronutrient status of Hosh, Suleimi and Laota soils was also investigated. The results show that they have what appears to be rather adequate indigenous reserves of essential plant micronutrients. Analysis of the CaCO(,3) concretions indicate that they contain less Cu, Fe and Zn than the soils that embodied them. However, these CaCO(,3) concretions have 10 to 20 times more Mn than do the soils. Available Mo in the soils of the Gezira scheme is low. The available levels of other micronutrients are within the ranges generally encountered in fertile soils. Correlations between plant uptake and soil available micronutrient cations indicated that several extraction solutions (DTPA, 0.01M CaCl(,2), 1N NH(,4)OAc, EDTA pH6.3 and EDTA + (NH(,4))(,2) CO(,3)) each showed a good potential for indexing micronutrient cations in the Gezira soils. The effect of soil moisture on the indigenous micronutrient cations (DTPA-extractable) was studied over an eight-week-period using an incubation technique. The results show that the DTPA-extractable Cu, Fe, Mn, and Zn were markedly reduced. In the coarse textured soil, the extractable Fe and Mn dropped to the lowest values within 2 weeks whereas, in the finer soils this required 5 weeks. Microbial activity apparently had little effect on the DTPA-extractable Cu, Fe, Mn, and Zn. The practical inference of this study is that the hot dry months which precede the growing season in the Gezira scheme increase the amounts of extractable micronutrients which may indicate greater availability.
Adam, Adam Ibrahim (1982). Mineralogy and micronutrient status of the major soils in the Gezira scheme (Sudan - Africa). Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -349825.