Temporal and spatial patterns of N2O emissions in maize/legume strip intercropping: Effects of straw incorporation and crop interactions

Context

Maize/legume intercropping presents a sustainable agricultural strategy to enhance nitrogen use efficiency and mitigate environmental impacts.

Research question

The impact of maize/legume strip intercropping on N₂O emissions, crop yields, and the associated mechanisms are not yet fully understood, particularly in the context of straw incorporation practices.

Methods

A two-year field experiment comparing five cropping systems (maize/peanut strip intercropping, maize/soybean strip intercropping, and corresponding monocropping) either with or without straw incorporation.

Results

Maize/legume strip intercropping increased yields by 15–24 % and reduced N₂O emissions by 15–22 % compared to the expected intercropping. This increase in yields, combined with the reduction in N₂O emissions, led to a 20–39 % reduction N₂O emission per unit of production in intercropped systems. The primary reduction in emissions occurred 7–10 days after the second fertilization, accounting for over half of the total emission reduction. Spatial analysis revealed that the majority of the reduction originated from the maize and interaction rows. Soil nitrate (NO₃^-) concentration emerged as the most critical factor influencing N₂O flux, with NH₄⁺ concentration also playing a significant role. Notably, straw incorporation did not increase N₂O emissions from intercropping systems, while yield tended to increase, albeit not significantly.

Conclusions

Maize/legume strip intercropping enhances nitrogen utilization, significantly mitigates N₂O emissions, and boosts crop productivity; however, these effects remain consistent regardless of straw incorporation practices.

Significance

This study highlights the advantages of maize/legume strip intercropping systems in reducing N₂O emissions and its potential contribution to crop production.