Forage and grain yields of dual-purpose triticale as influenced by the integrated use of <em>Azotobacter chroococcum</em> and mineral nitrogen fertilizer

Abstract

The utilization of dual-purpose cereals is encouraged in the Mediterranean environments to fill a feed gap during the winter season. Triticale is a promising dual-purpose crop for forage and grain production. Studies on the variations in productivity and quality of dual-purpose triticale under variable fertilization management are scarce. This study was carried out during winter 2018/2019 and 2019/2020, in Northern Egypt, to evaluate the performance of triticale grown in dual-purpose and grain-only production systems under variable mineral N (mN) rates (zero, 25, 50, 75% of the recommended), accompanied with Azotobacter chroococcum (AC) seed inoculation, as well as 100% mN application without AC. The application of 50% mN with AC seed inoculation resulted in an average of 7.23, 7.27 t ha–1, forage and grain yields, respectively. Moreover, forage and grain crude protein reached 125.57, and 200.60 g kg–1, respectively. Forage fibre fractions were non-significantly variable among the fertilizer treatments. Azotobacter chroococcum seed inoculation, thus, allowed for the reduction of the used amount of mN to 50% without sacrificing the forage and grain yields and protein content. In the dual-purpose system, an average of 7.23 t ha–1 forage yield was obtained with little reduction in the grain yield (19% reduction in average). Meanwhile, grain crude protein content was higher in dual-purpose system (201.38 g kg–1) than in grain-only system (182.98 g kg–1). In similar conditions to the current study, it is recommended to expand the production of dual-purpose triticale in the winter while reducing mN fertilizer rate to 50% in combination with AC seed inoculation.
 Highlights - Triticale is a promising dual-purpose crop that can be utilized for forage and grain production under irrigated Mediterranean conditions. - Around 7.23 t ha–1 forage yield was obtained from the dual-purpose triticale with a slight decrease (19% in average) in final grain yield. - Dual-purpose production system was profitable due to the good prices of triticale green forage in the region. - Azotobacter chroococcum seed inoculation allowed for the reduction of mineral nitrogen rate to 50% without sacrificing the forage and grain yields. - The integrated use of Azotobacter chroococcum seed inoculation with mineral nitrogen resulted in 43% decrease in fertilization costs.