The Effect of Water Quality and Irrigation Methods on Moisture and Salinity Distribution of Soil

Abstract

Current study was carried out with aim to evaluate the effect of pressurized irrigation methods and furrow irrigation method with municipal effluent on distribution of salinity and moisture in the soil profile. The experimental study was designed by split plot layout with three irrigation methods including furrow, surface drip (SD) irrigation and subsurface drip irrigation (SSD) and two water qualities (municipal effluent and fresh water) in a sugar beet field located in Corbal plain, Iran. Soil sampling was conducted in two sessions (prior to irrigation and after harvesting) at three depths of 0-20, 20-40, 40-60 cm and 15 points around areas where water leaked. Variance analysis of salinity showed a significant difference (p < 0.01) between irrigation methods, also between two water qualities in terms of salinity concentration, for three sampled depths of soil. The maximum value of salinity was found at the depth of 0-20 cm in subsurface drip irrigation by 1.66 dS/m, and the minimum value of salinity was found at the depth of 20-40 cm in furrow irrigation by 0.92 dS/m. Irrigation by municipal effluent caused a higher salinity concentration in the soil compared to fresh water regardless to the amount of water. Leaching operations, reducing the irrigation period and increasing the irrigation frequency, conducting researches and promoting the use of effluent are recommended in conclusion