A lysimeter experiment was conducted to study the shallow groundwater contribution in supplying maize water requirement. Twenty-four lysimeters, each consisting of a 1.2 m deep, 0.8 m diameter polyethylene pipe, were installed. Summer maize was planted in the lysimeters. The depth of groundwater table in the lysimeters was set to 0.6 m using Marriotte bottles. Three groundwater salinity levels (2.5, 5 and 7.5 dS/m) with two irrigation levels (at rates of 0.7 and 1 times of evaporation from pan class A at the before irrigation period) which replenished soil water on a weekly basis were used in the experiment. Factorial experiment in a randomized complete block design with three replications was established. In an individual treatment, maize was planted with full irrigation and No Ground Water (NGW) as the control treatment, replicated three times. The results indicated that groundwater contribution per cent at full irrigation level for each three salinity treatments (above mentioned) was 5.28, 4.61 and 3.76, and at deficit irrigation level was 25, 22.09 and 19.71, respectively. All differences were significant at the 0.05 Duncan's multiple ranges test. At deficit irrigation level, the grain yield reduction compared to control treatment was 23.57, 28.17 and 30.16% for three salinity treatments, respectively, and the dry matter reduction was also 37.50, 38.96 and 39.20%. At full irrigation level, the grain yield reduction was 19.42, 25.48 and 21.90% and the dry matter reduction was also 28.08, 33.60 and 25.78%. At full irrigation mode, the groundwater contribution decreased when the groundwater salinity increased and may be less evaporation from the soil surface causing less salt rising in the root zone and more relative yield.
