Two experiments were conducted at Water Studies and Research Complex (WSRC), Station, National Water Research Center, Toshka -Abu Simbel, during two growing seasons of 2018 and 2019 to compare available reference evapotranspiration (ET • ) equations (Hargreaves-Samani (HS), Makkink (MK), Priestley-Taylor (PT) and Turc (TC)) to the FAO-56 method to determine suitable alternatives for use in Toshka region, and to evaluation effects of drought stress and filter mud cake on physiological traits of two maize hybrids, three regulated deficit irrigation levels of available water content depletion (AWCD) I 1 , 13 %, I 2 , 25% and I 3 , 50% AWCD were combined with three levels of filter mud cake (FMC) F 1 : 4 kg m 2 , F 2 : 2 kg m 2 and F 3 : 0 kg.The data revealed that the individual influence of used 13% AWCD and FMC 4 kg m 2 , caused increases of the plant height (m), leaf area (cm 2 ), no. grains/cob, grain yield (ton/fed.) and water use efficiency (WUE) (Kg/m 3 ).The data also, revealed that the average seasonal values of the actual evapotranspiration (Eta) decreased as the percentage of soil moisture depletion increased (more available water extracted) . The Eta values were 1012.5, 853.1 and 712.7mm at 13, 25 and 50% AWCD, respectively.The data also, revealed that the grain yield in the first season (2017/2018) were 1.70, 1.32 and 0.77 ton/fed. While in the second season (2018/2019) were 1.85, 1.53 and 0.75 ton/fed for 13, 25 and 50% AWCD, respectively.The data revealed that increased regime treatment from 13 to 50% AWCD decreased WUE by maize plants from (0.45 to 0.29 kg/m 3 ) and (0.48 to 0.27 kg/m 3 )in 2017/2018 and 2018/2019, respectively.The results showed that the Hargreaves -Samani (HS) equation is suitable for estimating ETo for the studied area.

Macro elements availability in soils is an important aspect in context of soil fertility and agricultural productivity. This study was performed to determine the levels of some macro elements availability in El-kharga oasis soils, New Valley, Egypt. To achieve this goal, hundred surface soil samples (0-30 cm) were collected from El-Kharga and Barisoasis, New Valley, Egypt. The collected soil samples were subjected for chemical analyses. The obtained results showed that the dominant problems are salinity and low organic matter content, The summarized data showed that 35% of the samples have low available nitrogen and 65% have medium nitrogen which was associated with low organic matter (100% of the samples have less than 1% OM). However 91% of the samples have high available P(˃15mg/kg), where as 5% and 4% of the samples were categorized as low and medium available P. Also, 98% of the samples were high in available potassium and only 2% were medium. The high content of available P and K may be resulted from the parent material of El-kharga oasis. According to ECe, 49% of the samples have ECe less than 4dSm-1 , 51% of the samples were higher than 4dSm-1 , (21% medium, 16% high and 14% very high). Considering the soil pH and EC e , the results showed that 42% of the samples were non saline, 50% were saline, 6% were sodic soil and only 2%were saline sodic soils.

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The present. investigation was carried out to study the phosphorus status of different soil great -groups present in Qena Governorate .The soil in Qena Governorate is belonged to the following great -groups :Vtt, Eftt, Epqt and Eott. One hundred and five location samples distributed all over the entire area representing the soils of each great group in each territory of Qena Governorate were prepared. The P status of the soils of each great -group was assessed using a variety of chemical extraction methods. A pot experiment was also carried out to study the supplying power of P using Reygrass plants. The obtained results shows that:-The bicarbonate extractable inorganic P (NaHCO3-Pi) in the studied soil samples of different great -groups showed a wide variations that cooped with different chemical of these soils . The amount of Pi in the surface layers of the soils of all great-groups were noticeably higher than that of sub-surface ones. The bicarbonate extractable organic P ( NaCO3-Po) contents in the studied soils were different between soils of -great groups and among the soils of each great -groups. The values of total bicarbonate extractable phosphorus (NaHCO3-Pt) showed a considerable variation in Pt among various samples. The data also indicated that Pt in soil generally decreased as the soils became coarse in texture, low in organic content and in total CaCO3 content. P uptake by Raygrass was positively and significantly (P<0.05) correlated with both bicarbonate extractable P forms Pi and Po as well as the total bicarbonate extractable phosphorus Pt .The pearson simple correlation coefficients for the P uptake against Pi, Po and Pt were 0.7817**,0.7823**and 0.8215**, respectively.