Legumes and Safflower in Rotation with Barley Can Replace Barley Monoculture in Lebanon.
Sui Yau, American Univeristy of Beirut - FAFS, 3 Dag Hammarskjold Plaza 8th Floor, New York, NY 10017-2303 and John Ryan, ICARDA, PO Box 5466, Aleppo, Syria.
A long-term, rain-fed rotation trial was set up in 1994-95 in a semi-arid environment in the northern Bekaa Valley of Lebanon as a collaborative endeavor between the AmericanUniversity of Beirut and the InternationalCenter for Agricultural Research for the Dry Areas. One of the original objectives of the study was to ascertain if barley yield can be increased and sustained by including a legume crop in the rotation. Eight two-phase barley-based rotations were compared: barley in rotation with barley, lentil, common vetch, bitter vetch, common vetch for grazing, medics for grazing, common vetch for hay, and common vetch with barley for hay. Medics were dropped in 2002-03 and narbon vetch, cumin, safflower, and other treatments were added since 2000-01. The trial was discontinued in 2004-05. Data were analyzed using the ‘general analysis of variance’ option of the GenStat Package. Over the 9 years, there was no significant rotation by year interaction on barley grain yield, and all barley-legume rotations yielded better (44-95 %) than the barley monoculture, which also gave the most unstable yield over years. Barley-common vetch for hay gave the highest and a relative stable barley yield. Barley-lentil gave the most stable barley yield. In the last 2 to 4 years of the trial, barley-safflower was the highest yielding rotation after barley-fallow. Barley after safflower gave higher barley yield than after barley monoculture fertilized with 30 kg N/ha or 60 kg N/ha, 1 year of barley, 2 years of barley, cumin, and vetch for seed. The good performance of barley after vetch for hay and safflower was discussed. In conclusion, barley monoculture was unsustainable, but barley yields could be increased and sustained by including legumes and safflower in the rotation.