Determination of water requirements for wheat and maize under climate change is important for policy makers in Egypt. The objectives of this paper were to calculate (i) ETo and (ii) water requirements for wheat and maize crops grown in five governorates (Alexandria, Demiatte, Kafr El-Sheik, El-Dakahlia and El-Behira) located in North Nile Delta of Egypt under current climate and climate change. ECHAM5 climate model was used to develop A1B climate change scenario in 2020, 2030 and 2040. Monthly values of evapotranspiration (ETo) under the different scenarios in these governorates were calculated using Hargreaves-Samani equation (H-S). Then, these values were regressed on ETo values previously calculated by Penman-Monteith equation (P-M) and linear regression (prediction equations were developed for each governorate). The predicted ETo values were compared to the values of ETo calculated by P-M equation and the deviations between them were very low (RMSE/obs=0.04-0.06 mm and R2 =0.96-0.99). Water requirements for wheat and maize were calculated using BISm model under current climate and in 2020, 2030 and 2040. The results showed that average annual ETo would increase by low percentage in 2020 and 2030. However, in 2040 the increase would reach 8%. Water requirements are expected to increase by 2-3% for wheat and by 10-15% for maize, which would result in reduction of the cultivated area. Thus, it is very important to revise and fix the production system of wheat and maize, in terms of the used cultivars, fertilizer and irrigation application to overcome the risk of climate change.

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Two field experiments were conducted at Farm of Sids Agricultural Research Station, Egypt, during 2013 and 2014 seasons to study the effect of different irrigation regimes (I 1 = 100 %, I 2 = 85 % and I 3 = 70 % from irrigation requirements) and nitrogen levels (90, 120 and 150 kg N fed-1) on maize growth, yield and its yield attributes and some crop-water relationships. The most important results could be summarized as follows:Irrigated maize plants with full irrigation produced higher values of plant height, ear diameter, 100-grain weight, weight of grains ear-1 and grain yield as well as total amount of irrigation water applied, seasonal consumptive use and the net income. Irrigated maize plants with 80 % from irrigation requirements gave the highest values of water use efficiency and utilization efficiency.Supplied maize plants with 150 kg N fed-1 induced highest values of the abovementioned growth, yield and its attributes and net income as well as improve seasonal consumptive use, water use efficiency and utilization efficiency.Irrigated maize plants with full irrigation requirements and supplied with 150 kg N fed-1 produced highest yield and net income of maize plants.

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his study was intended to investigate whether dietary supplementation with different levels of nanoselenium (NSE) may reverse the negative influences of lead (Pb) contamination on growth, whole body composition, Pb residue in the tissues, and blood components in Oreochromis niloticus. The fish (n=180; 16.97±0.71 g) were allocated randomly into six equal groups as follows; the first group was fed the control diet, and the second was fed on the control diet contaminated with 80 ppm Pb (LW). From the third to the sixth groups (NSE0.2, NSE0.3, NSE0.4, and NSE0.5) were fed LW diet fortified with NSE at 0.5, 1.0, 2.0, and 4.0 mg nano-selenium/kg diet, respectively for 112 days. Results showed that fish LW group displayed significantly impaired growth performance, feed intake, feed conversion, and blood biochemical (P≤0.01) compared with fish in the control group. In contrast, fish groups NSE0.2, NSE0.3, NSE0.4, and NSE0.5 had significantly increased final body weight, daily weight gain, relative growth rate, survival rate, and daily feed intake compared with fish in the LW group. Furthermore, feed conversion and Pb bioaccumulation in fish tissues as well as serum contents of creatinine, AST, and ALT were significantly decreased (P≤0.01) in enriched NSE groups compared to the LW group. However, a significant increase in the values of hemoglobin, total protein, and albumin was observed in all NSE supplemented groups. The maximum enhancement was noted in NSE0.5 in most of the tested parameters. In conclusion, supplementing O. niloticus diet with NSE at 0.2 to 0.5 mg/ kg diet ameliorated the negative impacts of Pb toxicity on growth indicators, Pb residue in the tissues, and blood components.