Adapting to diversified garlic-maize rotation systems by adjusting nitrogen application: assessing crop yield, nitrogen utilization, and nitrogen footprint

Abstract

Diversified crop rotation is crucial for maintaining sustainable agricultural production by improving resource use efficiency, balancing soil nutrients, and preserving biodiversity. Despite these benefits, there is a notable gap in research concerning the nutrient transport characteristics in cash crop-grain rotation systems. This study was to investigate: (i) the nitrogen (N) uptake and distribution among the different plant organs in rotation crops; (ii) the N footprint in different growth seasons in response to crop N fertilization and residual N in the soil; and (iii) the influence of environmental factors on the productivity and N footprint in cash-grain rotation systems. In the three-year rotation system, N fertilizer was applied at the rates of 220, 175, and 130 kg N eq ha-1 for maize, and 300 and 240 kg N eq ha-1 for garlic. Results showed that maintaining a high N application rate during the garlic season and appropriately reducing it during the maize season (G300M175) enhanced N transfer to the grains of maize, increasing maize N use efficiency by 18.9%, while simultaneously increasing garlic dry matter and N accumulation. While the maize yield remained stable, garlic yield decreased with the reduced N rate, resulting in a significant reduction in N footprint. Water supplies (precipitation and irrigation) positively impacted dry matter accumulation, N absorption and yield, while reducing N footprint in both crops. Elevated air temperature favored maize yield but hindered garlic production and raised garlic N footprint. Although N fertilizer increased N footprint per unit land area (NFa), it decreased the N footprint per unit N uptake by crops (NFn) while boosting crop yields. Maintaining a suitable N input rate for cash crops in previous season while reducing N input in the following season staple crops can enhance the whole systems' productivity while decreasing the nitrogen footprint.