Effect of Irrigation Levels and Emitters Depth on Soil Moisture and Salinity Distribution and Water Use Efficiency of Tomato.
Abdrubalrasol Al-Omran and Sami Al-Damry. Soil Science Dept, King Saud Univ, Riyadh, 11451, Saudi Arabia
The scientifically applied research program related to water saving and conservation in agriculture is essential in Saudi Arabia, where agricultural activities account for more than 85% of total water consumed. The present study aims to investigate the effect of four irrigation levels and depth of emitters on tomato yield and Water Use Efficiency (WUE), and the distribution of salts and roots in sandy calcareous soils. A field experiment was conducted at the college experimental station in 2004-2005 season. It consists of three emitters' depth (15, 25, and 35 cm) below the soil surface, besides the surface drip irrigation treatment, and four irrigation levels of 60, 80, 100, and 120% of ETo. Soils samples were taken at depths of 0, 15, 30, 50 and 70 cm along the root zone depth. Results indicated the tomato fruit yield was significantly increased with the increase in irrigation water level. Generally, WUE values were increased as linearly with applied irrigation water and decreased at higher irrigation level. Early results showed that emitter depth affected yield and WUE, and emitter at depth 25cm gave a better yield. Also, results indicated that moisture content of subsurface layer increased dramatically, while salts were accumulated at surface away from the emitters in subsurface drip irrigation. The advantages of subsurface drip irrigation were related to the relative decrease in salt accumulation in the root zone area where the plant roots were active and water content relatively higher.