Maize/Soybean Intercropping with Nitrogen Reduction: A Pathway for Improved Nitrogen Efficiency and Reduced Environmental Impact in Northwest China

Research conducted by Wenjuan Shi and colleagues at Xi'an University of Technology found that maize/soybean intercropping combined with reduced nitrogen topdressing can improve nitrogen use efficiency and reduce environmental impact in Northwest China. The study, which was funded by the National Key R & D Program of China and the Doctoral Dissertation Innovation Fund of Xi'an University of Technology, used field experiments to investigate the effects of reduced nitrogen topdressing on system productivity, nitrogen dynamics, and environmental outcomes. The findings suggest that this approach can support more sustainable nutrient management practices in the region.

Key Takeaways:

• The study revealed that maize/soybean intercropping reduced crop yield due to decreased planting density, but improved maize nitrogen status compared to traditional monoculture.
• Intercropping reduced soil nitrate nitrogen residue by approximately 10% and NH3 volatilization by over 20% compared to maize monoculture.
• The intercropping improved nitrogen balance and environmental sustainability, enhancing maize nitrogen partial factor productivity by 26.76% (2023) and 23.63% (2024).
• Reducing nitrogen topdressing effectively minimized nitrogen residue and ammonia volatilization without compromising intercropping yield or nitrogen efficiency.
• The study concluded that this approach can support more sustainable nutrient management practices in Northwest China.
• Authors Wenjuan Shi, Bo Jing, and Tao Chen contributed to the research, which was conducted at Xi'an University of Technology.

Statistics:

• 25%, 50%, 75%, and 100% of the conventional nitrogen topdressing rate (240 kg ha(-1)) were applied in the study.
• The land equivalent ratio (LER) for intercropping was 1, indicating a yield advantage.
• Maize yielded 26.76% (2023) and 23.63% (2024) more nitrogen partial factor productivity than traditional monoculture.
• Soil nitrate nitrogen residue was reduced by approximately 10%.
• NH3 volatilization was reduced by over 20% compared to maize monoculture.

Sources:

• Shi, W., et al. "Maize/soybean intercropping with nitrogen reduction: a pathway for improved nitrogen efficiency and reduced environmental impact in Northwest China." _Soil & Tillage Research_ (Elsevier), 2025;253 (234): 316.
• National Key R & D Program of China and the Doctoral Dissertation Innovation Fund of Xi'an University of Technology
• Xi'an University of Technology, State Key Lab Water Engn Ecol & Environm Arid Area, Xian 710048, Shaanxi, People's Republic of China