Water sources can be exposed to contamination risks from agricultural, domestic and industrial activities. The appropriateness of water for agricultural irrigation can be known by determination of some physico-chemical parameters. Present study aims to assessment water quality of some fresh and drainage water sources in Kafr El-Sheik, El-Qalyubia and El-Fayoum Governorates, Egypt for use in irrigation of agricultural concurring to FAO guidelines for irrigation and drainage water. This was performed during summer 2023 and winter 2023/2024. Data revealed that pH of water sources was within the permissible limit (6.5 - 8.5). Salinity and sodicity values varied from 0.226 to 0.672 dS m-1 and 3.78 to 20.53 % for fresh water and from 0.26 to 3.04 dS m-1 and 2.67 to 21.51% for drainage water, respectively. Corresponding to USDA diagram (1954), the investigated samples are in class C1S1 to C4S4. Nitrate (NO3-) and ammonia (NH4+) concentration exceed the critical limits FAO (1985). In most samples, nitrogen (N) is outside the recommended limits values, but phosphor (P) and potassium (K) are in permissible limits for irrigation water. Biological oxygen demand, chemical oxygen demand and heavy metals concentrations in most samples were blow the allowable FAO irrigation limits and Egyptian water quality standards.
Adjusted sodium adsorption ratios (adj.SAR) in most of samples were above 9. According to USDA (1954), the soluble sodium percent (SSP) over maximum limits (60%) in most water samples. Permeability index (PI), Residual Sodium Carbonate (RSC) and Magnesium Adsorption Ratio (MAR) values in most samples > 75%, < 1.25 mmolc L-1 and < 50 %, i.e. no permeability, good and safe for irrigation, respectively. Potential salinity (PS) varied from classified as good, moderate and unsuitable. Kelly Ratio (KR), for all water sources were above the acceptable limit of 1.0 except End Bilibies drain (D6) and Middle Bilibies drain (D5) values are below the acceptable limit. These findings support the idea that drainage water in the study locations shouldn't be utilized for farming before being treated to prevent soil, agricultural, food security, and health protection from deteriorating.