Maize/soybean intercrop over time has higher yield stability relative to matched monoculture under different nitrogen-application rates.

Global demand for food continues to grow as a result of rising incomes and population growth. Meanwhile, the sustainability of food production is affected by climate change and agricultural soil degradation. The objective of this study was to evaluate the dynamic changes of maize/soybean yield, yield stability and soil fertility under mono-cropping and intercropping systems with different nitrogen application rates. The yield stability and sustainability of maize and soybeans were studied from 2017 to 2020 (Northeast Agricultural University, Acheng Experimental Site) according to the changes in crop yield, actual yield loss index, soil fertility over time as well as the differences in coefficient of variation and sustainable yield index under different cropping patterns in the maize/soybean intercropping system. This study established three cropping patterns (maize monoculture, soybean monoculture, and maize/soybean intercropping) with four nitrogen application rates (0/0 kg N ha–1, N0; 180/40 kg N ha–1, N1; 240/80 kg N ha–1, N2; 300/120 kg N ha–1, N3) based on the two-factor split block design. The maize and system yield indicated that intercropping was superior to the corresponding monoculture throughout the four-year experiment. With the extension of planting season, the yield from intercropping with nitrogen treatment (N1, N2 and N3) was higher than that without nitrogen treatment (N0). The yield stability of the intercropping system was also higher than that of the matched monoculture system. The coefficient of variation of the intercropping system was 18.83 % on average, which was lower than that of the matched monoculture system. In four years, the average contribution rate of soil fertility in intercropping treatment was higher than that in monoculture treatment. The structural equation model results suggested that the effect of nitrogen application rate on yield and yield stability was greater than that of cropping pattern. The yield and yield stability of maize/soybean intercropping over time was higher than matched monoculture under different nitrogen application rates due to higher soil fertility contribution in intercropping. This study provides theoretical evidence for maintaining the sustainability of legume and cereal intercropping and improving food security in the increasingly intensive global cropping systems. • Maize/soybean intercropping over time improved stability of crop yields. • Soil fertility contribution rate in intercropping was higher compared to monoculture. • Contribution rate of N fertilizer to maize yield stability was greater than soybean. • Influence of fertilizer on yield stability was greater than that of cropping pattern. [ABSTRACT FROM AUTHOR]