IRRIGATION WATER UTILIZATION AS A FUNCTION OF SOIL MECHANICS AND ITS PROPERTIES

An experiment was conducted for identifying the most efficient tillage method using the sub-soiling plough for enhancing some of physical properties of the heavy clayey soils. The experiment was conducted on a heavy clayey soil of an area 1800 m² located in Serewa village – Belqas – Daqahlia. This area divided into 4 adjacent plots, each one has a dimensions of (9m x50m) and was allocated only, for one treatment. The surface irrigation was the system applied and the amount of irrigation water added was equal for each plot (22.5m³) and was applied at the same time for all plots. Furthermore, an accounting for the rate of water flux in mm/day beneath soil profile along subsequent ten days from saturation was the last objective of this research. Only, four treatments were involved in this research as  (Treat.1):  sub-soiling plough at 40cm depth with a lateral spacing of 150cm, (T2): sub-soiling plough at 60cm depth with a lateral spacing of 150cm, (T3): sub-soiling plough at 40cm depth with a lateral spacing of 300cm and (T4): sub-soiling plough at 60cm with a lateral spacing of 300cm. For all plots, the sub-soiling plough was followed by chisel plough at 20cm depth and laser-controlled leveller at the dead level. All the data obtained clearly indicated that, the second treatment (T2) achieved the highest mean value of soil infiltration rate (2.2 mm/h) over all treatments and the lowest mean values for the cone penetration resistance, water content and bulk density at the surface layer of soil profile after tillage (2.41 M.Pa), (17.74 % w/w) and (1.17 g/cm³), respectively. Whereas, at saturation, it achieved the highest mean value of the water content (62.78 %w/w) and the lowest mean value of penetration resistance (.01 M.Pa). On the other hand, the mean value of the water content rested in the soil of the second treatment at the tenth day from saturation was (24.68 %w/w), producing the highest water flux (4.29 mm/day). Also, the second treatment achieved the shortest period of time needed until all amount of the deluge imposed on the soil surface after irrigation be completely infiltrated (20 h.).