Saturday, 15 July 2006

Variability of Soil Physical and Chemical Properties as Affected by Flood Spreading in Musian Station (South Western Iran).

Reza Soleimani, Soil and Water Research Institute, Ilam, Iran

Coarse grain sediments have very low capacity in moisture retention, so that rain divert to runoff. Spreading of flood, decreased the velocity of that and settled the associated materials and cause sedimentation. Also, flood spreading induced the important variabilities in environment, especially on soil. Simulation and monitoring are methods of studding these variabilities. Monitoring is the determination of variation trend of soil properties by using the sequential determination of important properties. Benchmark sampling is used for monitoring. Sampling from the same locations were obtained and variability trend was achieved. In Musian station, high amounts of sediment be settled and affected by flood spreading, annually. Therefore, trend of this variabilitis was a major research requirement. Study area was in Musian plain in south of Ilam province with coordination of 32o27/N and 47o25/ to 47o42/E. Therefore first gathered information, reports and plans from overall conditions of flood spreading field. Then sampling locations were determined. For detection of variabilities trend, first, second and third bonds be selected. Control site defined as locations that not affected by flood spreading. Therefore, after selection of bonds and control site, sampling was achieved by systematic-randomized method. By 18 cross section in each bond, ideal samples from diagnostic horizons and depths were obtained . After physical and chemical analysis of samples, mean comparison of data with T-test and statistical analysis be achieved by SPSS and MSTATC softwares. Analysis of data and means showed in table 1 and table 2. Results indicated that variability in sand and silt were significant in level of 1%. Means of those were 84.2 and 10.9 percent in control and were 79.7 and 14.6 percent in flood spreading field. In other hand, increasing clay percent in flood spreading field respect to control was not significant, but that of soil saturation was significant statistically. So, increased from 22.9 percent in control to 24.5 percent. Also, organic carbon and total nitrogen were higher in flood spreading field respect to control field. So that increasing in these cases in conditions of control and flood spreading were 30.1 and 33.3 percent, respectively. Variations of pH, EC, TNV and available potassium in flood spreading respect to control were not significant. Differences between dissolved cations and anions, variation of dissolved calcium and sodium in flood spreading respect to control were significant.

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