Optimiziranje izrabe virov pri skupnem gojenju soje (Glycine max (L.) Merr.) in koruze (Zea mays L.) v Srednjem Egiptu

The agronomic and economic performance of soybean–maize intercropping under different irrigation regimes and soybean planting densities was assessed during two field seasons (2022–2023) in Egypt. Three irrigation levels were applied: 120 % ETc (optimal), 100 % ETc, and 80 % ETc. Maize was grown at the recommended density in both sole and intercropped systems, while soybean was intercropped at 50 %, 65 %, and 75 % of its recommended density. Increasing soybean density enhanced soybean yield but reduced maize grain yield due to interspecific competition, particularly under drought stress conditions. The highest land equivalent ratio (1.61) was achieved with 75 % soybean combined with full maize density. All intercropping treatments recorded water equivalent ratios greater than unity, with maximum water-use efficiency (1.41) observed at 50 % soybean density. Intercropping significantly increased soil nitrogen and available phosphorus compared with sole maize, with greater improvements at higher soybean densities. Economic analysis revealed that 75 % soybean–100 % maize combination produced the highest economic returns across irrigation regimes. Despite yield reductions under water stress, intercropping consistently outperformed monocropping in productivity and profitability. Soybean–maize intercropping is a sustainable approach to enhance land and water use efficiency, soil fertility, and farm income under water-limited conditions.