Studying impact of flood water spreading on changes of vegetation and topsoil in koh khajeh flood spreading station, Sistan

The purpose of this research is to study the changes in some features of the topsoil and vegetation in the land affected by flood and comparing its results with the control area in koh khajeh flood spreading station in hamoon area of Sistan. For this purpose, four sites were considered as flood spreading area and two sites were selected as control area. Samples were taken in six sites using the random-systematic method. To this aim, 3 transects of 100 meters was established in each field and each one had 10 plots of 1 square meters regarding the dispersion of vegetation. Canopy cover percentage and density were calculated through use of plots and clipping and weighing was used to measure current year's growth as production. Also, to measure soil properties, sampling along each transect and in six points (3 points in shrubs understory and three points in bare soil), and factors as EC, pH, nitrogen percentage of the soil, and organic matter percentage were calculated. In order to compare the results regarding soil features, we used 2*2 factorial tests and for the factors regarding vegetation we used non-paired t test in spss. Data normality was assessed using Kolmogorov test. The results indicated that flood water spreading has a significant effect on canopy cover percentage and plant production respectively in probability level of 5 and 1 percent, but there is not significant difference between vegetation density in flooded and control area. Results showed that flood has led to significant increases in soil nitrogen percent and organic matter as well as low acidity and EC in probability level of 5 %.at the same time, organic matter, nitrogen and acidity are low compared to shrub understory soil in both treatments. However, EC in soil under shrub is higher than bare soil in both treatments.