Production advantage of crop-ley pasture-livestock mixed farming over pure-cropping system under climate change

The adoption of crop-livestock mixed farming systems offers product diversification and reduces reliance on external inputs compared to traditional cropping systems. However, the impact of rotation design on the production benefits of mixed farming under climate change remains unclear. This study used the well-validated APSIM model to assess the performance of mixed farming systems across historical and future climate scenarios. We established six reference crop rotations, including wheat, canola, field pea, oats, and barley, and introduced six crop-lucerne rotations with sheep grazing to represent the mixed farming systems. Across the Riverina Plain, soil nitrogen accumulation during the pasture phase in the mixed system was 66.3 kg ha⁻¹ year⁻¹ during the historical period, increased to 80.4–94.4 kg ha⁻¹ year⁻¹ under future climates. Nitrogen accumulation contributed to a crop yield advantage over pure-crop systems, with historical increases of 28.1%, 23.0%, 54.8%, and 8.9% for wheat, barley, oats, and canola, respectively. Under future climates, the yield advantage of the first wheat crop after lucerne was constrained, while other crop sequences exhibited enhanced yield benefits. Ley biomass and sheep production were closely related to rainfall availability. In middle and eastern Riverina, mixed systems showed a significant gross margin advantage over pure-crop systems during the historical period; however, it exhibited 0–250 AUD ha⁻¹ year⁻¹ lower in the drier western areas, except in cases where oats were included in the rotation. The economic disadvantage in dry areas would gradually diminish in the future. The mixed system with wheat-canola-wheat-canola showed the highest gross margin across all climate scenarios, while the wheat-field pea-wheat-oats sequence exhibited the greatest gross margin improvement compared to the pure-cropping system. This is a pioneering study on the performance of crop-livestock mixed systems under climate change, offering implications for farming system improvement in the study area and similar regions.