EURASIAN JOURNAL OF SOIL SCIENCE

10 - 15

Authors: Rosa María Rosales Aranda, Pedro Martinez-Pagán, Angel Faz Cano

The optimal detection and quantification of contamination plumes in soil and groundwater by petroleum organic compounds, gasoline and diesel, is critical for the reclamation of hydrocarbons contaminated soil at petrol stations. Through this study it has been achieved a sampling stage optimization in these scenarios by means of the location of potential contamination areas before sampling with the application of the 2D electrical resistivity tomography method, a geophysical non destructive technique based on resistivity measurements in soils. After the detection of hydrocarbons contaminated areas, boreholes with continuous coring were performed in a petrol station located in Murcia Region (Spain). The drillholes reached depths down to 10 m and soil samples were taken from each meter of the drilling. The optimization in the soil samples handling and storage, for both volatile and semi-volatile organic compounds determinations, was achieved by designing a soil sampler to minimize volatilization losses and in order to avoid the manual contact with the environmental samples during the sampling. The preservation of soil samples was performed according to Europe regulations and US Environmental Protection Agency recommendations into two kinds of glass vials. Moreover, it has been taken into account the determination techniques to quantify the hydrocarbon pollution based on Gas Chromatography with different detectors and headspace technique to reach a liquid-gas equilibrium for volatile analyses.

22 - 27

Authors: Mahtali Sbih, Antoine Karam, Adrien N’Dayegamiye, Zoubeir Bensid, Amar Boukaboub

The microbial biomass (MB) and light fraction (LF) of organic matter are often considered as active fraction of organic matter (AFOM) and as indices of soil fertility and microbial activity. This study was performed in order to assess the turnover of AFOM using long-term incubation (56 weeks) at25 °Cin 34 meadow soils with different physical and chemical properties such as soil texture, organic C and total N. The MB and LF were determined at 8 and 5 times during the incubation period using fumigation-extraction technique for MB and densimetric method for LF. The amount of MB-C and MB-N mineralized increased with time of incubation. At the beginning of incubation, the C and N content of soil MB represented respectively 0.76 to 3.7% of total organic C and 1.94 to 10.7% of total N. The C and N content of LF represented respectively 2.9 to 25.6% of total organic C and 1.7 to 17.5% of total N. At the end of incubation, the losses of MB-C and MB-N from soils reached respectively 71 and 82% of the initial amounts. The MB and LF dynamic were well described by a two-component first-order rate model. The amount of N in the labile MB and LF pools represented respectively 54% of total MB-N and 61% of total LF-N. The more stable MB and LF pools had higher half-life than labile pools. The results obtained indicated that the stable LF would be the precursor of soil humic compounds.

34 - 39

Authors: Tayfun Aşkın, Rıdvan Kızılkaya, Rezan Yılmaz, Vladimir Olekhov, Natalya Mudrykh, Iraida Samofalova

In present study, geostatistical techniques was applied to assess the spatial variability of exchangeable cations such as; calcium (Ex-Ca2+), magnesium (Ex-Mg2+), potassium (Ex-K+) and sodium (Ex-Na+) in the tillaged layer in a Perm State Agricultural Academy Farm site in Perm region, West Urals, Russia. A 250x100 m plot (approximately 2.35 ha) was divided into grids with 25x25 m spacing that included 51 sampling points from 0-0.2 m in depth. Soil reaction (pH) was the least variable property while the Ex-K was the most variable. The greatest range of influence (237.6 m) occurred for Ex-Ca and the least range (49.7 m) for Ex-Mg.

45 - 50

Authors: Mustafa Ismail Umer, Shayma Mohammad Rajab

Two Russian soil type, soddy-podzolic soil from Vladimerskaya region and dark-gray forest soil from Korskya region were taken .some microbiological parameters were assyed as basal respiration, substrate induced respiration, microbial biomass, microbial metabolic coefficient and correlated with soil aggregate stability concerning soil organic matter ,soil texture and soil bulk density . The result shown a positive correlation between all microbiological parameters with soil aggregate stability at this rank, microbial metabolic coefficient > microbial biomass = substrate induced respiration > basal respiration. Microbiological parameters and soil aggregate stability in dark-gray forest soil are greater than soddy-podzolic soil except basal respiration as a result of high organic content in this soil as will as the biomass as a percent of soil total organic matter. aggregate disintegration coefficient of dark-gray forest soil is 0.0028 with R2 0.927 and need 85 rain drop (equivalent to an energy of 83385 J Kg-1) greater than soddy-podzolic which had disintegration coefficient 0.0039 with R2 0.849 and needed only 40 rain drop (equivalent to an energy of 39240 J Kg-1).

58 - 63

Authors: Asghar Besalatpour, M. Ali Hajabbasi, Shamsolah Ayoubi, Ahmad Jalalian

A few areas in a large watershed might be more critical and responsible for high amount of runoff and soil losses. For an effective and efficient implementation of watershed management practices, identification of these critical areas is vital. In this study, we used the Soil and Water Assessment Tool (SWAT, 2009) to identify and prioritize the critical sub-basins in a highly mountainous watershed with imprecise and uncertain data (Bazoft watershed, southwestern Iran). Three different SWAT models were first developed using different climate input data sets. The first data set (denoted as CRU) was derived from the climate research unit data set developed by the British Atmosphere Data Center (BADC). The second data set (denoted as CDW) was included the climate data obtained from the precipitation and air temperature stations in the study area. The third set (denoted as COM) was a combination of CRU and CDW climate data. The Generalized Likelihood Uncertainty Estimation (GLUE) program was used for calibrating and validating the SWAT model. Daily rainfall, temperature, and runoff data of 20 years (1989-2008) were used in this study. In results, the constructed SWAT model using COM data set simulated the runoff more satisfactorily than the two other developed SWAT models according to the statistical evaluation criteria. The correlation coefficient and Nash-Sutcliff values for the constructed SWAT model using COM data set were 0.40 and 0.38, respectively. The model simulated the runoff satisfactorily; however, the predicted runoff values were much more in agreement with the measured data for the calibration period than those for the validation period. Sub-basins S10, S12, and S13 were assigned as the most top critical sub-basins in runoff production in the watershed. The study revealed that the SWAT model could successfully be used for identifying the critical sub-basins in a watershed with imprecise and uncertain data for management purposes.