Correia, P. J.Martins-Loução, M. A.2011-11-232011-11-231993Physiologia Plantarum 89: 669-672. 19930031-9317http://hdl.handle.net/10451/4549This paper is part of the contributions to the Proceedings of the 3rd Internacional Symposium on Inorganic Nitrogen Assimilation, held in Tiberias, Israel, 6-11 September, 1992A combined fertilization and irrigation experiment was initiated in order to see whether such treatment could improve the productivity of carob (Ceratonia siliqua L. cv. Mulata) on Mediterranean marginal lands. Mature carob trees (20–30 years old) were submitted to 3 different irrigation levels (100%;, 50%; and 0%;) based on daily standard evaporation values, measured with a class A pan. For each water level either 21 or 63 kg N ha−1 was applied as ammonium nitrate. The results reported here refer to a two-year experiment, and show that the productivity of the trees could be improved due to a positive interaction between water and N application. In addition, they suggest that also under the normal dry conditions of these Mediterranean systems nitrogen application is effective, even without irrigation.engCarob-treeCeratonia siliquaFruit productionInflorescensesIrrigationN-nutritionjournal article