Optimizing canola growth and biochemical attributes using diluted sewage effluent as an alternative irrigation source

Sewage effluent (SE) is increasingly being recognized as a sustainable water resource, particularly in regions facing freshwater scarcity. SE is rich in macronutrients such as nitrogen (N), phosphorus (P), and potassium (K), which enhance soil fertility and crop productivity. However, it also contains contaminants, including heavy metals, organic pollutants, and pathogenic microorganisms, that can adversely affect plant biochemical processes, soil health, and crop quality. To mitigate these risks, effective management strategies such as filtration, dilution, and biological treatment can reduce toxicity and improve its suitability for agricultural use. This study investigates the optimal dilution of SE for cultivating different canola varieties (CON III, AARI Canola, Punjab Canola, and Faisal Canola) under controlled conditions. The experiment was conducted using a completely randomized design with four replications, comparing SE and tap water treatments. Results revealed that Punjab Canola exhibited the highest performance under SE treatment, with significant increases in shoot length (51.99%), shoot dry weight (66.96%), leaf number per plant (47.55%), flowering branches per plant (55.34%), and seed oil content (9.87%) compared to the control. Photosynthetic pigments, including chlorophyll a (59.80%), chlorophyll b (39.28%), and total chlorophyll (56.38%), were also markedly enhanced in Punjab Canola under SE application. Additionally, improved concentrations of N, P, and K in roots and shoots demonstrated the effectiveness of SE in promoting nutrient uptake across the tested varieties. These findings suggest that diluted SE can serve as an effective and sustainable alternative to conventional irrigation, significantly enhancing canola growth and productivity while addressing the water scarcity challenge.