EURASIAN JOURNAL OF SOIL SCIENCE

1 - 19

Authors: Désiré Tsozué, Rose Yongue-Fouateu

Soils developed on garnet-rich micaschist in the Southern Cameroon plateau were investigated. Morphologically, two weathering materials constituted the study profile, fine earth and nodules. Each material has a singular evolution from the coarse saprolite to the upper set of clayey and loose horizons. There is Al2O3 enrichment in the fine earth concomitantly to Fe2O3, Na2O and K2O enrichment in nodules in major element–Al2O3 variation diagrams. A–CN–K and A–CNK–FM diagrams show a progressive depletion of Al in nodules concomitantly to an enrichment of this element in the fine earth. Three pedogenetic processes emerge from the evolution of weathering products. There is a ferruginization process whose importance increases from the coarse saprolite to the upper set of clayey and loose horizons, giving rise to the formation of dense nodules composed of hematite, goethite and gibbsite. This ferruginization occurs concomitantly with a desaluminization process, which causes Al2O3 depletion in nodules. These nodules are formed by the process of induration where the hydrated amorphous hydroxide and oxides are dehydrated to their crystalline oxide form, due to condensation. In addition, there is aluminization, which occurs in the fine earth, leading to the development of a red clayey material composed of kaolinite and gibbsite.

28 - 36

Authors: Mushtaha Ali, Abdalla Elhagwa, Jamal Elfaki, Magboul Sulieman

Twenty soil samples were collected from North of Atbara (Dar-Mali locality),River Nile State, Sudan (17.82289 to 17.82389N and 33.99974 to 34.02127E) inside and outside gold mining area in order to assess the influence of the gold mining on the concentrations of selected heavy metals (Co, Cu, Fe, Mn, Ni, Pb, Zn, Hg) in study area. The soil contamination by heavy metals of study area was studied using two parameters; (i) Comparison of the heavy metals concentrations with mean concentrations in most world soils, (ii) Enrichment Factor (EF). Results revealed that the concentrations of heavy metals were varying in the study area, the highest concentrations were obtained at the center of mining area particularly inside the mining basins of gold extraction. The concentrations of Cu, Fe, Mn, Zn, Co, Ni, and Pb were ranged from (4.85 to 34.65 mg kg-1 soil), (6,355 to 14,635 mg kg-1 soil), (37.35 to 655 mg kg-1 soil), (11.85 to 42.7 mg kg-1 soil), (0 to 16.5 mg kg-1 soil,) (2.5 to 47.3 mg kg-1 soil) and (2.65 to 823.5 mg kg-1 soil), respectively. The results also indicated that the soil samples which collected from inside mining basins have a highest EF for most heavy metals particularly Pb, which showed EF value of (676.3), suggesting that the Pb may be derived from anthropogenic source. This study recommends regular monitoring of heavy metals in the soils around the Artisanal gold Mining for conservation and protection from pollution.

44 - 50

Authors: Sergey V. Makarychev, Andrey G. Bolotov

The goal of this study was to determine the conductive and steam-diffusive heat transfer constituents in the soil. Based on the solution of differential equation system of heat and mass transfer, the method to determine the conductive and steam-diffusive heat transfer constituents in wet soils was developed. To measure the thermophysical properties in laboratory setting, a pulse method of a two-dimensional heat source was used. The method takes into account the patterns of temperature field equalization in an unbounded medium after the heat source termination. A feature of this process is the occurrence of peak temperature at the investigated point of the medium at a given instant. In this experiment, the temperature was controlled not only at the investigated point of the medium, but also at the soil-heater interface. The proposed method was used to study the thermophysical indices of the chernozems of the Altai Region’s Priobye area (the Ob River area). The chernozem under study is of light-loamy particle-size composition; the illuvial horizon В is enriched by a sand fraction. It has been found that the soil conductive thermal diffusivity is reduced with increasing moisture content. The steam-diffusive thermal diffusivity has the extremum at the moisture close to the discontinuous capillary moisture. In humus horizons it plays a smaller role than in the mineral horizons. The thermal diffusivity determined by the steam molecule motion in the pore space of the soil exceeds the conductive thermal diffusivity two or three times. At the same time thermal steam diffusivity is more than ten time lower than the conductive constituent. Eventually, the stem molecules though dramatically accelerating the processes of heat transfer in the soil profile conduct a small amount of heat and make a weak contribution to soil thermal accumulation.

59 - 64

Authors: Martin Šeda, Jan Šíma, Tomáš Volavka, Jan Vondruška

Contamination of soils with three metals due to the highway and railway transport was studied. Copper was selected as a suitable indicator for both kinds of transportation. Sodium served to assess the level of contamination resulting from the road salting in winter. Mercury was determined in samples taken close to the railway in order to test its release from impregnated wooden ties. All analyses were determined using the methods of the trace element analysis; values are expressed as dry matter. The highest concentrations of copper, sodium and total mercury in soil samples were 52.7 mg/kg, 770 mg/kg and 0.181 mg/kg respectively. The highest copper content was observed in soils taken close to the railroad and the highway. Elevated sodium levels originated from winter road salting – the highest winter value was 770 mg/kg as compared with maximal summer value of 416 mg/kg. The concentration of total mercury in soils depended on the type of railway ties used – the highest values for location with wooden and concrete ties were 0.181 mg/kg and 0.145 mg/kg, respectively. Wooden railroad ties are considered as a potential source of mercury because of impregnation with antifungal mercury compounds.

75 - 83

Authors: Reza Sokouti, Davood Nikkami

Soil erosion hazard is one of the main problems can affect ecological balance in watersheds. This study aimed to determine the optimal use of land to reduce erosion and increase the resident's income of Qushchi watershed in West Azerbaijan province, Iran. Income and expenses for the current land uses were calculated with field studies. Damages resulting from the soil erosion were estimated by soil depth equal to the specified land uses. For three different options including the current status of land uses without and with land management, and the standard status of land uses, multi-objective linear programming model was established by LINGO software. Then the optimization problem of the land use was solved by simplex method. Finally, the best option of land use was determined by comparing erosion rate and its cost in each scenario. Then the circumstances and the recommended conditions were compared. The results indicated that the current surface area of current land uses is not suitable to reduce erosion and increase income of residents and should change in the optimum conditions. At the optimum level, there should change horticulture area of 408 to 507 (ha), irrigated land area of 169 to 136 (ha) and dry farming of 636 to 570 (ha), while conversion of rangeland area not indispensable. In addition, the results showed that in case of the optimization of land use, soil erosion and the profitability of the whole area will decrease 0.75% and increase 3.68%, respectively. In case of land management practices, soil erosion will decrease 42.27% and the profitability increase 21.39% while in the standard conditions, soil erosion will decrease 60.95% and profitability will increase 24.20%. The results of the sensitivity analysis showed that the changes in the horticulture and range land areas have the greatest impact on the increasing profitability and reducing soil erosion of Qushchi watershed. So, it is recommended using Education and Extension to promote the importance of land management to understand how proper use of the land.