Agronomic evaluation of legume-barley intercropping systems in a Mediterranean dry area.
Aurelio Pristeri, Demetrio Tortorella, Antonella Scalise, Giovanni Preiti, Antonio Gelsomino, Michele Monti
Dipartimento di Biotecnologie per il Monitoraggio Agro-Alimentare ed Ambientale (BIOMAA), Università degli Studi “Mediterranea”, Salita Melissari 89124 - Reggio Calabria
In the Mediterranean region, legume/cereal intercrops (IC) are commonly grown for forage production but few studies were carried out to evaluate their performance. Research activities carried out by UDM in the Legume Futures Project (www.legumefutures.de) addressing this are reported here.
The main aim of the study was to assess the effect on crop yield of intercropping two grain legume species (field pea and faba bean) and barley and to estimate how these legume can support the wider cereal cropping system.
A field experiment (winter sown) has been carried out in San Marco Argentano (It) (39°38’N, 16°13’E, 100 m a.s.l.) during 2010-2011 growing season. The experiment was established on a coarse silty, mixed, thermic soil (Fluventic Xerochrept). Mean annual rainfall is 709 mm and mean air temperature was 16.1°C (averages over the 1995-2009 period). The plot experiment used a randomized block design with 4 replicates. A medium early six-row barley (Hordeum vulgare L. cv. Aldebaran) was intercropped with two legumes: faba bean (Vicia faba L. sub minor cv. Sikelia) and a leaf-less medium early, field pea (Pisum sativum L. cv. Hardy). Pure stands of the three species were sown at the recommended seed density of 40, 90 and 300 plants m-2 for faba bean (F100), field pea (P100) and barley (B100), respectively. Three cropping treatments were examined: pure stand controls sown at 100% the normal pure stand seeding rate; a replacement pattern with half pure stand densities of barley and legumes combined (P50B50 and F50B50); and an additive pattern with barley at half the normal pure stand seeding rate combined with 100% seeding of the legumes (P100B50 and F100B50). The soil was fertilised with 36 kg N ha-1 and 92 kg P2O5 ha-1 as diammonium phosphate at sowing. No fertilisers, herbicides and pesticides were used after sowing. Analyses were performed at harvest for grain yield and crop and weed biomass determination, nitrogen content of grain and N2-fixation (Ndfa%).
Pure stand grain yields were higher than usually obtained in the region under commercial farming conditions confirming that the varieties chosen are well adapted to the region and that results obtained are regionally representative.
The response to intercropping was greater for the pea/barley combinations than for the faba bean/barley combinations, particularly for P50B50 where the grain yield of each component of the pea/barley intercrop was at least 80% of the corresponding pure stand. The better performance of pea/barley was associated with better control of weeds. It also fixed more N2.
The advantage arising from the complementary use of resources by intercrops is clear the Land Equivalent Ratio (LER) for grain yield which was higher than 1 in all intercrops. The pea and bean based intercrops were 23 and 68% higher yielding than their components grown separately. This is an example of ecological intensification of cereal systems of Mediterranean area that can also improve farmers’ income.