Using some surroundings around surface drippers to be used as sub-surface

This work aims to reduce the costs of subsurface irrigation system by using surface drip lines. Also to study the impact of using some surroundings media around subsurface dripper lines on the amount of irrigation water, soil moisture distribution, salt content distribution, water use efficiency (WUE), soil water storage and onion yield. This work was conducted on sand soil at a private farm, Badr El Hedaya Society Center ,in Governorate of El Bohera during seasons (2004 and 2005). It was used irrigation water had 1.4 ds/m. Five treatments: T(1) was surface drip irrigation system with irrigation level 100% from irrigation requirements, T(2), T(3), T(4) and T(5) were subsurface drip irrigation system (SSDIS) with surroundings of sponge, stones, sponge with stones and without sponge with stones respectively with irrigation rate 80% from irrigation requirements. The irrigation interval for the last treatments was every day (daily irrigation). These treatments were repeated with each three days as irrigation interval in T(6), T(7), T(8), T(9) and T(10), respectively. However the results show that: Amount of irrigation water were 1972.1 and 1577.7 m. /fed for 100% with SDIS and 80 % with SSDIS crop water requirement respectively. The best Soil moisture distribution was for after irrigation by using stone (T3) with 80% crop water requirement. Then before irrigation the best treatment was T(5). * The salt content distribution (EC) of the five treatments irrigated each three days are higher than the other five treatments for daily irrigation. * Water use efficiency (WUE) It is prefer to use treatments of sponge with stones (T(4)) under using SSDIS with daily irrigation rather than for three days intervals. * The best soil water storage at three days irrigation SDIS with 100% IR (T (6)) and at T(9) without surroundings under using 80% IR and SSDIS. * The highest yield was T(5) SSDIS with 80 % of crop water requirement with daily irrigation interval with 10.327 ton/fed.