EFFECT OF NATURAL CLAY DEPOSIT AND THE QUALITY OF IRRIGATION WATER IN SOME WATER CHARACTERISTICS OF SANDY SOIL

Abstract

An experiment was carried out in the greenhouse (Department of Soil and Water Resources - College of Agriculture, University of Baghdad) for the purpose of revealing the impact of fresh (tap) and saline irrigation water (Well - Faculty of Agriculture - University of Baghdad) in the viability of sandy soil on water retention with different rates of natural clay deposits added (0%, 1%, 2%, 3%, and 4%) available in the banks of the Tigris and placed in plastic cylindrical columns of 5 cm in diameter and 36 cm in height. Natural clay deposits were added to a depth of 5 cm from the surface of the column material mixed with sand, and the application of the fresh and saline water continued at the level of the field capacity weekly, and the daily evaporation was calculate the for a period of four weeks from the beginning of the experiment. Results showed that the irrigation of sandy soil with saline water has led to a decrease in its ability to retain water and to an increase in the daily and cumulative evaporation with the existence of natural clay deposits compared to fresh water irrigation treatment. The rate of 2% was the best rate of the natural clay deposits added to the surface layer (0-5cm) to decrease the cumulative evaporation in the sandy soil columns irrigated with fresh and saline water. Results showed that the penetration resistance of the soil has increased significantly when saline irrigation water added (0.26 kPa), as compared with the fresh irrigation water (0.23 kPa). The relative swelling rate of sandy soil was increased with increasing rates of added natural clay deposits when irrigated with saline water compared with fresh water, and the percentage increase in the rates of addition of natural clay deposits in comparison with the control .Treatment was 170%, 395%, 637%, and 1025% When saline irrigation water added and 68%, 220%, 415%, and 805% when fresh irrigation water added, respectively. Results showed that irrigation of sandy soil with saline water affected its ability to water retention compared with fresh water for all treatments.