Physical and Chemical Soil Properties as Affected by the Flood Spreading in Garehcharyan Plain, Zanjan

Flood spreading is one of the suitable methods to control the floods and conservation of soil and water in arid and semi-arid regions. Since soil properties may be influenced by the flood spreading, this study was carried out to investigate the effect of the flood spreading on physicochemical soil properties in Garacharyan plain located in North West of Zanjan in 2009. Three flooded areas and one control area were selected for soil sampling. Two hundred sixteen soil samples and twenty seven soil samples were taken from three flooded areas and control area, respectively. Soil infiltrability was also measured at three points both in the flooded areas and in control area. Results of the physical soil properties indicated that the soil infiltrability and available water content were significantly (p< 0.001) affected by the flood spreading in the study plains. With a decrease in sand percentage and an increase in clay in the flooded areas, soil infiltrability strongly declined. The available water content negatively correlated (p< 0.001) with clay in the areas. Soil chemical properties, including salinity, potassium, and bicarbonate, contrary to pH and total neutralizing carbonates and nitrogen, significantly (p< 0.001) increased in the flooded areas as compared with control area. Increasing of the salinity in the flood plains is associated with potassium in the flood plains (p< 0.001). There was no significant difference in organic matter and carbonate contents between the flooded areas and control area. The study revealed that controlling suspended load and solvent solids in the floods is necessary to prevent the degradation of the soil physicochemical properties (porosity, infiltration, plant water supply, and salinity and bicarbonate) and as a result improve the effectiveness of the flood spreading method in the flooded areas.