A field experiments was carried out at Sakha Agric. Res. Sta. Farm
during two successive summer seasons (2002 and 2003) to study the effects
of water regime, nitrogen fertilizer levels and zinc application on maize yield
and its water relations as well as some soil chemical properties. Split-split plot
design with four replicates was used, where 4 water regime treatments (40%,
55%, 70% and 85% depletion of available soil moisture) were occupied the
main plots. Nitrogen fertilizer with three levels (90, 110 and 130 kg N red' )
were placed in the sub-plots and three zinc treatments (150 ppm zinc-EDTA
chelate as a foliar spray application, 10 kg fed' Zn- sulfate as soil application
and without zinc applied) were allocated to sub-sub-plots. The main results could be summarized as follows:         -     There was a significant effect of water regime on maize yield and its
components. Irrigation at 55% depletion of available soil moisture (1₂)
produced the highest maize yield and its components. While the irrigation
at 85% depletion of available soil moisture (14) gave the lowest maize
yield. Increasing nitrogen fertilization level up to 130 kg ted' highly Significantly
increased maize yield and its components. The foliar application of zinc produced the higher maize yield than the SOil
applied zinc. - The highest amount of irrigation water applied and water consumptive use
(WCU) were obtained with irrigation at 40% depletion of available soil
moisture. While the irrigation at 85% depletion of available soil moisture
gave the highest values of crop water use efficiency (CWUE).        -      Soil salinity (ECe), soluble ions and SAR were decreased with increasing
the amount of irrigation water applied. On the other hand, decreasing the
amount of irrigation water applied (14 Treat.) led to salts accumulation in
the soil profile during both seasons. Generally, it could be concluded that increasing nitrogen fertilization level
up to 130 kg tee" and irrigation at 55% depletion of available soil moisture
with 150 ppm foliar spray of zinc gave the highest maize yield and its
components