Assessment of kernel composition and dry milling quality standards in a flint maize hybrid following hairy vetch and nitrogen fertilization

Abstract

Dry milling industry demands kernels with strict quality standards. While synthetic nitrogen (N) fertilization is mainly applied to secure yield, it is rarely used to improve kernel quality, and alternative sources may enhance system sustainability. This study evaluated the potential of hairy vetch (Vicia villosa Roth.) to supply N for meeting industry standards in a single flint maize (Zea mays L.) hybrid. Field experiments were conducted during the 2022/23 and 2023/24 seasons under rainfed and no-till conditions, comparing fallow versus hairy vetch with different sowing and termination dates, and with or without N fertilization in maize. Kernel yield, composition, and quality parameters were determined, and their associations with N synchronization during kernel filling were analyzed. Nitrogen synchronization ranged from 10 to 52 % across vetch management treatments, with early sowing combined with late termination accumulating more N than late sowing with early termination. Greater synchrony increased vitreousness and screen retention, and reduced flotation index, but had no effect on test weight. Protein concentration declined with improved synchrony, while starch and oil remained unchanged. On the other hand, N fertilization reduced flotation index, tended to increase screen retention, and raised kernel protein concentration, but had no effect on vitreousness or test weight; while oil and starch responses were inconsistent across seasons. Overall, quality attributes were within industry standards. These findings highlight vetch as a N source to satisfy market requirements and to be adopted under favorable economic and production contexts.