It is important to determine soil salinity with an accurate and simple method. Electrical conductivity (EC) of soil-water extracts is commonly used to assess soil salinity because it is an easier method than the standard saturated paste extract (ECe). However, it is essential to convert EC of soil-water extracts to ECe because plant response and salinity remediation are based mainly on ECe values. Our objectives were to develop and validate models to predict ECe from EC of 1:2.5 and 1:5 soil-water extracts (EC1:2.5, EC1:5). One hundred thirty-six coarse textured soil samples were collected from El Beheira Governorate, Egypt, of which 115 were used to develop models and 21 were used to validate these models. Electrical conductivity was determined using 1:2.5 and 1:5 soil-water extracts and saturated paste extracts (ECe). Linear regression models were established for the two methods. The results showed that ECe was highly significant correlated (R 2 = 0.96 to 0.97, P < 0.001) with EC1:2.5 and EC1:5 for ECe values ranging between 0.3 and 18.3 dS m-1. An independent validation set of 21 soil samples showed that the R 2 and slopes of the regressions between predicted ECe from both EC1:2.5 and EC1:5 values and direct ECe values were very close to 1.0. Additionally, these new models reduced ECe prediction errors by 2.4 to 7 times when compare with 8 predictive models reported in the literature. Confirming that the regressions developed can reliably assess soil salinity instead of the more timeconsuming and expensive saturated paste extraction.

Improving soil water holding capacity (WHC) through conservation agriculture (CA)-practices, i.e., minimum mechanical soil disturbance, crop diversification, and soil mulch cover/crop residue retention, could buffer soil resilience against climate change. CA-practices could increase soil organic carbon (SOC) and alter pore size distribution (PSD); thus, they could improve soil WHC. This paper aims to review to what extent CA-practices can influence soil WHC and water-availability through SOC build-up and the change of the PSD. In general, the sequestered SOC due to the adoption of CA does not translate into a significant increase in soil WHC, because the increase in SOC is limited to the top 5–10 cm, which limits the capacity of SOC to increase the WHC of the whole soil profile. The effect of CA-practices on PSD had a slight effect on soil WHC, because long-term adoption of CA-practices increases macro- and bio-porosity at the expense of the water-holding pores. However, a positive effect of CA-practices on water-saving and availability has been widely reported. Researchers attributed this positive effect to the increase in water infiltration and reduction in evaporation from the soil surface (due to mulching crop residue). In conclusion, the benefits of CA in the SOC and soil WHC requires considering the whole soil profile, not only the top soil layer. The positive effect of CA on water-saving is attributed to increasing water infiltration and reducing evaporation from the soil surface. CA-practices’ effects are more evident in arid and semi-arid regions; therefore, arable-lands in Sub-Sahara Africa, Australia, and South-Asia are expected to benefit more. This review enhances our understanding of the role of SOC and its quantitative effect in increasing water availability and soil resilience to climate change.

Region of Alex-Cairo Desert Road (Egypt) has agricultural potentiality to contribute to food security; therefor the soil of the farm of Nile Company, at 63 Km Alex-Cairo Desert Road, was evaluated by applying our comprehensive analytical approach of evaluation. Soil physical and chemical characterization conducts to soil numerical classification and crops soil suitability that has the advantage to guide the practices of soil management and reclamation.Soil physical characterization leaded to univariate numerical soil classification that pointed that the major phases were moderately soil profile depth (1996.76 Feddan), moderately permeability (3543.90 Feddan), low holding capacity (2608.11 Feddan) and sandy loam textural phases (1800.83 Feddan). Soil chemical characterization led to univariate numerical soil classification which showed that the major classes were moderately saline (3124.76 Feddan), non-sodic (3531.04 Feddan) and non-calcareous classes (3851.35 Feddan).The study referred to selection salt tolerant crops as cultural practice for managing soil salinity. Leaching requirements (LR) of reclamation purposes, for different EC-tolerance crops, were determined to output GIS-EC edaphological map. This map that may guide the process of saline soil reclamation was composed of four mapping units having the area of 298.76, 3124.76, 845.35 and 16.11 Feddan. The map that determined the spatial distribution of (LR) application showed that: the max allover total leaching water requirements (ATLR) of 13189090.54 m 3 are to cultivate all studied area by orange. (b) Wheat is more salts tolerant than orange. Accordingly, the max allover total leach requirements were 1557042.70 m 3 /studied soil to plant wheat, which were less greatly than the case of orange cultivation. GIS-ESP edaphological soil classification was elaborated by assigning ESP thresholds of tolerant crop range to GIS-ESP soil map to produce the GIS-ESPedaphological map. The map divided the studied area into three categories of ESP tolerance crop soil; extremely sensitive ESP crop (1355.09 Feddan), sensitive ESP crop (2845.73 Feddan) and moderately tolerant crop (84.88 Feddan). This edaphological soil classification enabled to calculate edaphological gypsum requirement (GR) for different ESP-tolerance crops. GIS-EC and ESP overlaid maps output the soil multivariable chemical classification. The overlaid GIS-EC-map classified the studied soils into five variants; non saline-non sodic soil (298.80 Feddan) moderately saline-non sodic soil (2701.42 Feddan), highly saline-non sodic soil (535.95 Feddan), moderately salinesodic soil (424.04 Feddan), and highly saline-sodic soil (325.47 Feddan)Land suitability determined the main limitation factors to guide soil management and reclamation. Wheat soil suitability classified the soils into of the area was conditionally suitable (S4 =57.3%) and (S3 = 42.7%). As for faba bean, the soils had the three classes; marginally suitable (S3= 47.6%), conditionally suitable (S4 = 30.7%), and moderately suitable (S2 = 21.7%). G...

Life of Egypt is substantially linked to the Nile River. The Nile River is the principal source of water in Egypt which is used for purposes such as agriculture, drinking, electricity generation and industry. The Water Quality Index (WQI) is a valuable and simple tool for announcing and explaining massive dataobtained from any body of water. Remote sensing can be a useful tool in the water quality monitoring. WQI is applied, in thispaper, to evaluate suitability of Nile water for irrigation usage, in Rosetta River Nile branch, El-Beheira governorate, Egypt. Water samples were collected from six various sites about 65 km stretch along Rosetta River Nile branch at almost equal distances, starting from Kafr El-Zayat city to Idfina Barrage. Polyethylene plastic bottles (1 Liter capacity) were used to collect water samples. Samples were assessed for eight (8) Chemical parameters, namely pH, electrical conductivity, Sodium, Potassium, Calcium, Magnesium, Bicarbonate and Chlorides. The regression analysis is used to investigate the correlation between WQI and remote sensing data (ASTER images). The results showed that the water quality index were mostly good for irrigation purposes according to FAO guidelines (WQI values between 50-100), except for site 1 which had a poor class (WQI values between 100-200) because of the artificial pollution at it. The electrical conductivity and sodium concentration were the most important characteristics affecting the calculated water quality index of the study area. Band 1 of ASTER images showed the highest correlation coefficient with WQI (R 2 = 0.86) according to logarithmic regression analysis.

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