Mechanized Harvesting Performance of Intercropped Cardoon and Safflower: A Comparative Study with Monocultures

Diversified cropping systems, such as intercropping, are increasingly evaluated for their capacity to enhance biodiversity, resource-use efficiency, and economic stability under climate change conditions. This study investigates the mechanized harvesting performance of intercropped cardoon (Cynara cardunculus L.) and safflower (Carthamus tinctorius L.) compared to their respective monocultures. Field validation trials were conducted over three consecutive growing seasons under rainfed conditions at the Maccarese trial site in Central Italy, utilizing a conventional multi-crop combine harvester. The agronomic results demonstrated that intercropping achieved a clear land-use efficiency benefit, yielding the highest total biomass at 22.96 Mg ha.¹ with a Land Equivalent Ratio for biomass of 1.32. However, the structural heterogeneity of the mixed canopy created severe mechanical bottlenecks during single-pass machine harvesting. Slower operating speeds and heavy volume processing increased the operational harvesting cost of intercropping to 98.61 € ha.¹, whereas the cardoon monoculture achieved the highest field efficiency and lowest cost at 70.24 € ha.¹. Furthermore, mechanical limitations in cutting and threshing dissimilar plant structures induced substantial seed losses within the intercropped system (0.425 Mg ha.¹), resulting in a deficit in seed recovery efficiency. These findings highlight that while a cardoon-safflower combination optimizes raw vegetative biomass supply chains, the lack of specialized harvesting hardware remains a primary constraint for dual-purpose oilseed recovery.