## 4 Conclusions  
In this study, we examined the influence of different watering regimes applied to Coratina cv. trees grown on ameliorate karst soils in Croatia, with respect to oil quantity, composition and quality. Olive trees were subjected to rainfed conditions and three different irrigation treatments (T\({}_{1}\)--deficit irrigation representing the usual producer's practice, T\({}_{2}\)--regulated deficit irrigation in respect to phenological stages, T\({}_{3}\)--full irrigation) during two years of investigation. Our results indicated that Coratina cv. olive trees grown on the karst soil in Croatia could produce EVOO of high quality under rainfed conditions, as well as under irrigated conditions, while under irrigation conditions, the quantity of obtained oil is higher. Carotenoids content decreased in oils obtained from irrigated fruits, but differences among different irrigation treatments were not determined in both years of investigation. On the other hand, the irrigation effect on chlorophyll content was contradictory across the two years of investigation. PUFA and linolenic acid contents decreased in all irrigation treatments compared to rainfed treatment, with no significant difference among different irrigation regimes. In general, irrigation influenced a decrease in volatile compounds involved in the specific green odor of VOOs. Watering regimes applied did not significantly affect the concentration of total phenolic compounds and secoiridoids determined, while the concentration of simple phenols increased in all irrigated treatments. Intensities of fruitiness, bitterness and pungency of Coratina cv. oils from rainfed trees grown on karst soil in Croatia were robust and the detected decrease of bitterness in irrigated treatments could have positive effects on consumer acceptance of this oil. No difference between T\({}_{3}\) (100% Etc treatment) and deficit irrigation treatments (T\({}_{1}\), T\({}_{2}\)) in oil composition indicated that similar VOO quality could be achieved with less demand in water supply. Our results also indicated that T\({}_{2}\), \"smart agriculture\" treatment, although it had not produced statistically different results in quantity and quality of oil in regard to other irrigation regimes investigated, enabled precise and automatic water rate application, thus greatly increasing water usage efficiency while saving energy and human labor. Additionally, this strategy resulted in sustainable water saving due to a reduction of water needed for irrigation between critical phenological stages (flowering, pit hardening and oil accumulation). The obtained results could help producers to define a suitable irrigation management scheme in the particular condition of ameliorate karst in Croatia to obtain olive oil of high quality but also to produce a greater quantity of oil. Since the year of harvest could have great influence on the olive oil composition, continued investigation of irrigation in the karst soil conditions in Croatia during more harvesting years is needed. Conceptualization, T.K., S.M. and K.B.B. ; methodology, K.B.B., S.M., T.K., A.G.P. ; formal analysis, D.K., A.N., K.B.B., M.J.S. ; investigation, T.K., S.M., S.K., M.Z., K.B.B., D.K., A.N., A.G.P. ; resources, T.K. and Z.S. ; data curation, K.B.B. and D.K. ; writing--original draft preparation, K.B.B., S.K., M., A.G.P., Z.S. ; writing--review and editing, K.B.B., S.K., T.K., D.K., A.N., A.G.P., M.J.S., Z.S. ; visualization, D.K., K.B.B., S.M., A.G.P. ; supervision, T.K. ; project administration, T.K. ; funding acquisition, T.K. All authors have read and agreed to the published version of the manuscript. This research was funded within the project \"Smart Agriculture Network\" (SAN--KK.01.2.1.0100) co-financed by the European Union (\"IRI--Research, Development and Innovation\"), Operational Program \"Competitiveness and Cohesion\" 2014 th till 2020 th.