Maize and soybean intercropping enhanced soil nutrient availability and crop adaptability under simulated nitrogen deposition.

As a significant global atmospheric pollution issue, excessive nitrogen (N) deposition harms plant and soil. Meanwhile, the maize-soybean intercropping is a popular farming system that improves soil fertility and crop yield. Nonetheless, research on the response of maize-soybean intercropping to N deposition remains scarce. This research examined the response of maize and soybean in monoculture and the two-crop intercropping system to different N deposition levels (0, 50, 100, 150 and 200 kg hm-2 yr-1). The results showed that increased N deposition reduced chlorophyll fluorescence parameters and root growth in maize and soybean. At the same time, it limited soil nutrient accumulation and decreased soil microbial biomass carbon (C), Nitrogen (N), and phosphorus (P) contents (abbreviated as MBC, MBN and MBP, respectively). Relative to monoculture, intercropping increased maize and soybean chlorophyll fluorescence parameters and improved root morphology under 100 kg N ha-1 yr-1 N deposition conditions. Under 100 and 150 kg N ha-1 yr-1 N deposition levels, maize and soybean root C and N contents increased. Additionally, in the range of 0-200 kg N ha-1 yr-1 N deposition, intercropping increased soil MBP, available K and P content. Intercropping reduced the ratio of soil N/P under all N deposition levels. The intercropping system effectively mitigated the adverse effects of N deposition on chlorophyll fluorescence parameters in maize and soybean, improved the availability of main soil nutrients, and enhanced root growth in soybean. The findings of this study provide support for sustainable agricultural development. © 2025 Society of Chemical Industry.