Optimizing Crop Water Use with Saline Aquaculture Effluent: For Succesful Production of Forage Sorghum Hybrids

Hungary faces increasing water challenges, including frequent droughts and a growing dependence on irrigation, which necessitate alternative water sources for agriculture. This study evaluated the use of saline aquaculture effluent—characterized by elevated sodium (Na+) and chloride (Cl−) concentrations—as an irrigation resource for forage sorghum (Sorghum bicolor L.) over four consecutive growing seasons. Three hybrids (‘GK Áron’, ‘GK Balázs’, and ‘GK Erik’) were tested under five irrigation regimes, including freshwater and aquaculture effluent applied via drip irrigation at weekly doses of 30 mm and 45 mm, alongside a non-irrigated control. Effluent irrigation at 30 mm weekly increased biomass yield by up to 61% and enhanced nitrogen uptake by 22% compared to the control. Soil electrical conductivity (EC) values remained below 475 µS/cm, with effluent treatments showing lower EC than non-irrigated plots. The effluent water also supported the recycling of nutrients, especially nitrogen and phosphorus. Unlike conventional saline water, aquaculture effluent contains organic compounds and microbial activity that may improve nutrient mobilization and uptake. Our results highlight how we can reuse aquaculture wastewater in irrigated crop production. The results demonstrate that moderate effluent irrigation (30 mm/week) can optimize crop water use while maintaining soil health, offering a viable strategy for forage sorghum production in water-limited environments.