Effect of water drop energy of sprinkler irrigation on clay and silt particles transporation in different gypsifereous soils

Abstract

A laboratory study have been conducted to investigate the influence of sprinkler water droplets energy generated from nozzles with two flow rates (9 and 15 mm.hr-1) on soil aggregates and the displacement of soil particles in some gypsifereous soil samples. Five soil samples with different gypsum contents were prepared by mixing between low and high gypsum content soil samples. These soils were sampled from AP and C of profile horizons. The prepared soil samples of different gypsum contents were G0 (83), G1 (133), G2 (211), G3 (472) and G4 (592) gm.kg-1. After the incubation of the prepared for two months, the soil samples were passed through sieves of 2 and 4 mm openings to obtain soil aggregates ranged between 2- 4mm diameters. The soil aggregates were packed with a 6 mm thickness (13 gm) in a plastic tube underlined by pure sand with 26 cm length and an inner diameter of 5 cm. The tubes were placed in a moveable circular base with a 60 cm diameter and a circumference of 188.4 cm. The soil sample tubes were distributed randomly with a 37.6 cm separating distance separating. Each tube sets were subjected to 9 and 15 mm.h-1 sprinkler flow rates. The droplets size distribution for each sprinkler flow rate was studied as well as the droplets energy.The results showed that the droplets energy were increased with increasing droplets size and sprinkler flow rate. Maximum droplet energy was obtained with 1.5 mm droplet diameter, while the minimum droplet energy was obtained with 0.18 mm. Silt and clay transportation were decreased with increasing soil gypsum content under the two sprinkler flow rates. The high flow rate sprinkler was more effective on silt and clay transporting.