To investigate the capability of plants to utilize the different soil nutrients and hence their crop productivity and water use efficiency (WUE), a field experiment was undertaken in Ismalia, Egypt, during 1999 summer season. Maize, as an indicator plant, was grown under both surface drip irrigation (SDI) and subsurface drip irrigation (SSDI). Under both irrigation systems, 3 regimes of irrigation water were applied, i.e. 60, 80 and 100% of water consumptive use of maize in the area. Soil samples were taken every other day one time just before irrigation and another at ~7 h after irrigation to follow up the movement and distribution of soluble salts and moisture in the soil profile. The soluble salt accumulation phenomenon was followed up through the uppermost 10 cm of soil surface while the soil moisture was estimated every 10 cm of soil downward till a 60 cm soil depth. Soil salinity tended to increased in the soil surface with decreasing the irrigation regime under both irrigation systems. The soil moisture content retained was higher under SSDI than under SDI. Soil available N, P and K tended to increased as the irrigation regime decreased, while available Fe, Mn and Zn in the soil decreased with decreasing the irrigation regime. The SDI significantly increased the maize grain contents of N and P compared to SSDI. Grain and straw yields increased significantly under SSDI compared with SDI. The highest grain or straw yield was recorded with the highest rate of irrigation regime. The total contents (uptake) of N, P and K as well as Fe, Mn and Zn in maize grain increased significantly under SSDI compared with SDI. The medium level of irrigation regime (80%) recorded higher values of both maize grain and straw yields under SSDI than under SDI. The WUE was significantly higher under SSDI compared to SDI. It decreased with decreasing irrigation regime.
