Sustainable intercropping system of maize and sorghum with soybean for improved nitrogen and water use efficiency

Overview

This research proposes a sustainable intercropping system that combines maize or sorghum with soybean to improve nitrogen use efficiency and water use efficiency in cropping systems. The approach addresses two critical agricultural challenges: the rising cost of nitrogen fertilizers and the growing scarcity of water resources, particularly in Mediterranean-type climates. By growing cereals alongside nitrogen-fixing legumes, the system aims to better utilize environmental resources, reduce input costs, and maintain or increase production levels.

The intercropping approach leverages the complementary growth patterns of cereals and legumes. Maize and sorghum are globally important crops for both animal and human consumption, but their conventional cultivation requires substantial nitrogen fertilization and water inputs. Soybean, as a legume, can fix atmospheric nitrogen and potentially reduce the fertilizer requirements of the companion cereal crop. When grown together, these crops may achieve higher overall resource use efficiency than monoculture systems.

Technical specifications

Research design:

• Two nitrogen fertilization levels: zero nitrogen (control) and recommended fertilization of approximately 250 kgN/ha based on soil analysis
• Two water availability levels: 100% of reference evapotranspiration
• Five cropping systems tested: maize monocrop, sorghum monocrop, soybean monocrop, maize-soybean intercrop, and sorghum-soybean intercrop
• Field experiments conducted at the Aristotle University of Thessaloniki university farm in Greece
• Two-year experimental duration

Measured parameters:

• Morphological characteristics of all crops
• Physiological characteristics including nitrogen and water use efficiency
• Agronomical characteristics and yield components
• Resource utilization rates across different cropping systems

Target environment:

• Mediterranean-type climates where water conservation and nitrogen management are critical
• Areas facing rising fertilizer costs and limited water resources

Technology readiness level

This research is at an early experimental stage. The validation plan involves controlled field experiments at a university research farm to establish baseline data on how different cropping systems affect nitrogen and water use efficiency under varying input levels. The two-year study will generate empirical evidence on whether intercropping maize or sorghum with soybean can deliver the hypothesized improvements in resource efficiency. Results will inform whether this approach can be developed into practical recommendations for farmers in Mediterranean climates and similar regions facing fertilizer cost pressures and water limitations.