Dual-purpose barley and oat in a Mediterranean environment

In Mediterranean environments, forage production for livestock is both difficult and costly due to erratic rainfall. As an alternative, barley, oat and triticale can be used as dual-purpose autumn-sown cereals, thus serving as winter grazing and grain for feed. The present study was aimed at estimating the influence of different management systems (dual-purpose with one and two grazings, soft-dough harvest for silage, full maturity grain only) on grain yield, forage and whole plant production, and on quality-related traits of barley (Hordeum vulgare L.) and oat (Avena sativa L.). The trials were conducted over 2 years (1998/1999 and 1999/2000) in a Southern Italy Mediterranean environment using a flock of sheep for grazing and mechanically clipping the plots, thus simulating the dual-purpose, to obtain forage samples for analyses. Effect of the years was not significant, whereas both crops underwent significant reductions of grain yield, harvest index, thousand kernel weight and seeds/m(2) in the dual-purpose plots but not in the grain only plots. The most drastic yield reduction was recorded in oat after two grazings by comparison to the ungrazed treatment (2.4 t/ha versus 3.9 t/ha). Grain protein content was not affected by dual-purpose in oat, and it was independent of the number of grazings in barley. Barley had a higher production of total biomass and milk feed units than oat in the dual-purpose management systems, except for the soft-dough and grain only treatments. In addition, barley reacted positively to both the dual-purpose systems (one and two grazings). More specifically, whole plant biomass increased from 9.6 t/ha when grown for grain only to 13.6 t/ha in the single grazing system, and milk feed units similarly increased, from 7680 to 9216 MFU/ha. Green forage quality was comparable between the two cereals, even though barley whole plants showed lower fibre content, especially after two grazings. The soft-dough stage of both crops had better forage quality parameters, nevertheless, the lower biomass yields and total milk feed units (in the case of barley) rendered this system non-profitable for the environment studied. Barley demonstrated a clear superiority for the dual-purpose systems in Mediterranean Italy and should thus be preferred to oat, except when using oat to interrupt barley monocropping. (c) 2006 Elsevier B.V. All rights reserved.