Co-Authors:
Naor, A., Golan Research Institute, P.O. Box 97, 12900 Kazrin, Israel
Schneider, D., MIGAL, Galilee Technology Center, P.O. Box 831, 11016 Kiryat Shmona, Israel
Ben-Gal, A., Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Beer Sheba, Israel
Zipori, I., Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Beer Sheba, Israel
Dag, A., Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280 Beer Sheba, Israel
Kerem, Z., The Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, P.O. Box 12, 76100 Rehovot, Israel
Birger, R., Agriculture Valley Center, P.O. Box 73, 23100, Migdal Haemeq, Israel
Peres, M., Extension Service, Ministry of Agriculture and Rural Development, 12100 Kiryat Shmona, Israel
Gal, Y., Extension Service, Ministry of Agriculture and Rural Development, 12100 Kiryat Shmona, Israel
Abstract:
The interactions between irrigation rates applied during the oil accumulation stage and crop load were studied in a six-year-old very-high-density Koroneiki (Olea europaea L.) orchard. Five irrigation rates, determined as thresholds of midday stem water potential, were applied from July 1st until harvest in 2008 and 2009 and from July 1st to the end of September in 2010. Oil yield increased with increasing crop load in all the irrigation treatments. Oil yield did not respond to increasing irrigation at very low crop load and the higher the crop load the higher the response to irrigation. There was no response to irrigation at the lowest crop loads, but the higher the irrigation rate the higher the oil yield at high crop loads. The predicted commercial oil yield at common fruit counts increased from 1.99 t/ha at the lowest irrigation rate to 3.06 t/ha at the highest irrigation rate. Stomatal conductance decreased with decreasing stem water potential but leveled off at 30-60 mmol m-2 s-1 at stem water potential values lower than -4.0 MPa. High crop load increased stomatal conductance and decreased stem water potential relative to low crop load at low and medium irrigation rates. The effect of crop load on water relations became evident by the end of August and was well pronounced at the beginning of October. Physiological and irrigation water management implications related to the interactions between tree water status and crop load are discussed. © 2012 Springer-Verlag.