CONICET | Buscador de Institutos y Recursos Humanos

In the emerging olive growing regions of Argentina, the scheduling of irrigation is most often defined by a crop coefficient (Kc) in order to meet the demands of the crop and maximize yield. The coefficients employed have been derived from studies conducted under Mediterranean climate conditions without considering local conditions. The objectives of our study were 1) to determine a Kc for an arid region of Argentina and 2) to analyze the responses of vegetative growth, yield, and physiological parameters to different levels of irrigation. The experiment was conducted in a young, drip irrigated Manzanilla Fina orchard for table olives near Aimogasta, La Rioja (28°33 S. 66° 49 W), in northwest Argentina. Different irrigation levels were applied (Kc = 0.50, 0.70, 0.85, 1.0, 1.15) for two growing seasons.(2005-06, 2006-07). During the winter, Kc = 0.35 was maintained in all treatments. Shoot elongation and trunk cross-sectional area was strongly increased even by very high levels of irrigation during both seasons. In contrast, the individual fruit growth and fruit set were not affected although the number of fruits was reduced during the second year as a result of low vegetative growth in the lower irrigation levels during the first season. Yield were affected only during the second season and reached maximum values with a Kc of 0.85. The yield per unit of applied water was lower as the irrigation level increased (i.e.> Kc =0.85). However, the vegetative growth per unit of water did not decrease with increasing Kc despite the high levels of irrigation employed. The stem water potentials were more negative during both years with the lower irrigation treatments. In conclusion, a Kc value of between 0.70 and 0.85 maximized yield in arid Argentina and the water productivity of vegetative and reproductive growth showed different responses