Assessment of Furrow Length and Land Slope on Maize Yield, Irrigation Water Productivity, and Economic Feasibility Under Furrow Irrigation Method in Clay Soils

With increasing water scarcity and growing food demand, enhancing agricultural productivity has become a pressing necessity, aligning with the Sustainable Development Goals (SDGs). Maize is a strategic crop, yet under surface irrigation, modern technologies are required to optimize irrigation efficiency and reduce water losses. Two field trials were conducted during the summer seasons of 2024 and 2025 on a private farm in Banha, Qalyubia Governorate, Egypt, using a three-replication split-block design. This study evaluated three land slopes (0, 0.05, and 0.15%) and two furrow lengths (50 and 75 m) under furrow irrigation in clay loam soil, using the maize hybrid “Single Cross 2036.” The results demonstrated that both furrow length and land slope significantly affected all measured parameters. Shorter furrows (50 m) consistently outperformed longer ones (75 m), achieving better growth parameters, higher grain yield, improved harvest index, and enhanced irrigation water productivity. Regarding land slope, the 0.15% slope produced the best results, although it was not significantly different from the 0.05% slope in most cases. The interaction between furrow length and land slope was significant; the combination of 50 m furrows with 0.15% slope produced the highest values across all parameters. For longer furrows (75 m), the gentler 0.05% slope was more effective than the steeper 0.15% slope. Notably, 50 m furrows, even with 0% slope, performed better than 75 m furrows with the optimal 0.05% slope, indicating that furrow length is more critical than slope for maximizing maize productivity in clay loam soils. Economic analysis confirmed these findings, with the combination of 50 m furrows and 0.15% slope achieving the highest net return (29,565 EGP ha −1 ) and revenue-to-cost ratio (1.38), representing a substantial increase in net profit compared to traditional practices. Therefore, a 0.15% slope is recommended for shorter furrows (50 m), while a gentler 0.05% slope is more suitable for longer furrows (75 m). These findings provide a practical pathway for policymakers and farmers to enhance resource efficiency and contribute to SDG 2 (Zero Hunger) and SDG 6 (Clean Water and Sanitation).