Assessment of Different Leaching Treatments in Gated Pipe Irrigation System

Abstract

The objective of this paper is to study the assessments of four leaching treatments on some soil chemical properties, irrigation efficiency and crop production. Field experiments are conducted in a study area that has gated pipes irrigation system, sandy silt loam to clay loam texture and the main crop is cotton. The study area is located at western Delta, Egypt and it covers 2.8 ha with Mediterranean semi-arid climate. Four leaching treatments are applied to the study area. They are 50%, 75%, 100% and 150% of the original leaching requirement (L.R). Total soil salinity, sodium adsorption ratio, toxic and non-toxic salts are investigated before planting, mid-season and at the end of the season for each leaching treatment. Also, additional water efficiency, irrigation efficiency, and crop production are studied for each leaching treatment. The study reveals that the 150% L.R treatment is associated with minimum increase of the total soil salinity. Sodium adsorption ratio decreased for all L.R treatments throughout the growing season. All L.R treatments increased the toxic salts, especially 150% L.R treatment. The 50% and 75% L.R treatments increased the non-toxic salts, while the 100% and 150% L.R treatments decreased them. The highest values of both additional water efficiency and the total irrigation efficiency are associated with 50% L.R treatment. The maximum cotton production is associated with 100% L.R treatment, followed by both 50% and 75% L.R treatments. Six equations are obtained employing regression analyses to get the percentage of the increase of total salinity, the percentage of the decrease of Sodium adsorption ratio, the percentage ratio of the change of both toxic and non-toxic salts, and both the additional water efficiency and the total irrigation efficiency with respect to the leaching treatment. It is concluded that both 50% and 75% L.R treatments produced lower values of soil salinity at the end of the growing season, and simultaneously achieved increased crop productivity.